z Scores, Type I and II Errors, Hypothesis Testing

This is your second IBM SPSS assignment. It includes three sections in which you will:

1. Generate z scores for a variable in grades.sav and report and interpret them.
2. Analyze cases of Type I and Type II errors.
3. Analyze cases to either reject or not reject a null hypothesis.

Download the Unit 4 Assignment 1 Answer Template from the Resources area and use the template to complete the following sections:

• Section 1: z Scores in SPSS.
• Section 2: Case Studies of Type I and Type II Errors.
• Section 3: Case Studies of Null Hypothesis Testing.

Format your answers in narrative style, integrating supporting statistical output (table and graphs) into the narrative in the appropriate places (not all at the end of the document). See the Copy/Export Output Instructions in the Resources area for assistance.

Submit your answer template as an attached Word document in the assignment area.

The American Journal of Bioethics, 9(5): 31–36, 2009 Copyright c© Taylor & Francis Group, LLC ISSN: 1526-5161 print / 1536-0075 online DOI: 10.1080/15265160902788645

Target Article

Unintended Changes in Cognition, Mood, and Behavior Arising

from Cell-Based Interventions for Neurological Conditions:

Ethical Challenges P. S. Duggan, Johns Hopkins University, A. W. Siegel, Johns Hopkins University,

D. M. Blass, Johns Hopkins University and Abarbanel Mental Health Center, Bat Yam, Israel, H. Bok, Johns Hopkins University, J. T. Coyle, Harvard Medical School, R. Faden,

Johns Hopkins University, J. Finkel, Johns Hopkins University, J. D. Gearhart, Johns Hopkins University, H. T. Greely, Stanford University, A. Hillis, Johns Hopkins

University, A. Hoke, Johns Hopkins University, R. Johnson, Johns Hopkins University, M. Johnston, Kennedy Krieger Institute, J. Kahn, University of Minnesota, D. Kerr,

Johns Hopkins University, P. King, Georgetown University, J. Kurtzberg, Duke University, S. M. Liao, Oxford University, J. W. McDonald, Kennedy Krieger Institute, G. McKhann, Johns Hopkins University, K. B. Nelson, National Institutes of Health,

M. Rao, Invitrogen Corporation, Carlsbad, CA, A. Regenberg, Johns Hopkins University, K. Smith, Johns Hopkins University, D. Solter, Duke-National University of Singapore, H. Song, Johns Hopkins University, J. Sugarman, Johns Hopkins University,

R. J. Traystman, University of Colorado, A. Vescovi, University of Milan Bicocca, J. Yanofski, University of Texas Southwestern Medical Center, W. Young, Rutgers, State

University of New Jersey, D. J. H. Mathews, Johns Hopkins University

The prospect of using cell-based interventions (CBIs) to treat neurological conditions raises several important ethical and policy questions. In this target article, we focus

on issues related to the unique constellation of traits that characterize CBIs targeted at the central nervous system. In particular, there is at least a theoretical prospect that

these cells will alter the recipients’ cognition, mood, and behavior—brain functions that are central to our concept of the self. The potential for such changes, although

perhaps remote, is cause for concern and careful ethical analysis. Both to enable better informed consent in the future and as an end in itself, we argue that early human

trials of CBIs for neurological conditions must monitor subjects for changes in cognition, mood, and behavior; further, we recommend concrete steps for that monitoring.

Such steps will help better characterize the potential risks and benefits of CBIs as they are tested and potentially used for treatment.

Keywords: CNS, personal identity, risks, stem cells

The prospect of using cell-based interventions (CBIs) to treat neurological conditions raises several important eth- ical and policy questions, such as the permissibility of us- ing embryo- or fetal-derived cells, the permissibility of cre- ating human/nonhuman chimeras for research (Streiffer 2005; Robert 2006), what constitutes reasonable evidence

Acknowledgment: The authors acknowledge the contribution of Dr. Ira Black, who died before the completion of the manuscript. Address correspondence to D. J. H. Mathews, PhD, Johns Hopkins University, 624 North Broadway, Hampton House 352, Baltimore, MD 21205. E-mail: [email protected]

of safety and efficacy for purposes of allowing translation from animal models to human subjects research (Regenberg et al. 2008), and whether the rush to translation in stem cell research might itself impede advances in the basic biologi- cal research (Maienschein et al. 2008). In this target article, we focus on less well-charted issues related to the unique

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constellation of traits that characterize CBIs targeted at the central nervous system (CNS). In particular, there is at least a theoretical prospect that these cells will alter the recipients’ cognition, mood, and behavior—brain functions that are central to our concept of the self (especially to our personal- ity, character, and agency). Some changes, such as recovery of functions lost due to brain injury or disease, will be de- sirable and intended effects of the intervention. However, the potential for changes in recipients’ cognition, mood, or behavior, though perhaps remote, is cause for concern and careful ethical analysis: work that is made more difficult by the absence of data on which to judge the likelihood and magnitude of such changes.

Both to enable better informed consent in the future and as an end in itself, we argue that early human trials of CBIs for neurological conditions must monitor subjects for changes in cognition, mood, and behavior; further, we recommend concrete steps for that monitoring. Such steps will help better characterize the potential risks and ben- efits of CBIs as they are tested and potentially used for treatment.

CONTEXT

Concerns about changes affecting the self are motivated by factors relating both to the mechanism of action of CBIs and the site of intervention of such interventions for neurologi- cal conditions. First, the potential therapies under consider- ation involve novel CBIs: such therapies are poorly under- stood, when compared with pharmacological and surgical interventions that are more commonly employed. Second, the therapies are targeted at the CNS, and in many cases, specifically at the brain, where neural circuitries underlie the psychological characteristics that are central to the self.

It is important to keep in mind from the outset that the conditions for which CBIs are currently being consid- ered are serious, sometimes fatal, neurological conditions in which the brain is already functioning abnormally in some way (a notable exception being spinal cord injury). As such, we presume that most persons would view the risk of cognitive, affective, or behavioral changes as rela- tively insignificant compared with the potential benefits. Nonetheless, it is critical that during the informed consent process, the risks be characterized such that potential re- search participants have sufficient information to provide valid informed consent (Master et al. 2007; Mathews et al. 2008).

POTENTIAL CHANGES ARISING FROM CELL-BASED INTERVENTIONS

While current models of brain function may do a reasonable job of explaining aspects of many everyday cognitive func- tions as well as how pathological processes (e.g., dementias and other neurodegenerative disorders) can alter or dimin- ish those functions, it is considerably more challenging at this stage to extend these models to explain how the brain can be repaired or reorganized (e.g., in recovery from stroke) (Hillis 2005; Zhang et al. 2005) and how it might be “rebuilt”

using CBIs (e.g., in neurodegenerative disorders) (Lindvall et al. 2004; Oliveira and Hodges 2005). Given the gaps in our knowledge about the brain, any predictions we make about the risks of CBIs are highly speculative and perhaps prone to exaggeration. It is important to stress that the types of changes discussed here are hypothetical at this stage. Al- though it is difficult (some would argue impossible) to ex- trapolate the probability of higher-order functional changes from studies that employ animal models of the relevant neurological conditions (Regenberg et al. 2008), it is never- theless important to monitor for such effects in preclinical studies (Greene et al. 2005).

We likely will not have a clear picture of the risk pro- file for these types of interventions until clinical trials in humans are well underway. However, there are analogous cases from non-CBIs in humans in which such changes have occurred, demonstrating not only that such side effects are not novel, but also that they are tolerated in certain cir- cumstances. Medical management of Parkinson’s disease (PD) has been associated with serious side effects, rang- ing from levodopa-induced dyskinesias (involuntary move- ments) to striking behavioral changes such as development of pathological gambling problems (Dodd et al. 2005). Deep brain stimulation for PD and other movement disorders has been shown to induce changes in mood such as de- pression or mania (Bejjani et al. 1999; Berney et al. 2002; Kulisevsky et al. 2002) and changes in behavior, such as hy- persexuality (Temel et al. 2006). Electroconvulsive therapy, which can be effective for otherwise treatment-refractory depression, is known to cause transient cognitive problems (Datto 2000; O’Connor et al. 2003; Schulze-Rauschenbach et al. 2005). Even treatment for non-neurological conditions may induce neurological changes. For example, a number of common drugs (e.g., naproxen, diphenhydramine) can cause cognitive changes in the elderly (Goodwin and Re- gan 1982; Agostini et al. 2001), although such changes are reversible by stopping drug administration (this effect is not anticipated to be the case for CBIs, for which the in- tervention consists of living cells), and cancer treatment can cause cognitive changes in women with breast cancer (Burstein 2007), though the reasons for such side effects are not necessarily clear. While these are merely analogies—and there may be no reason to believe that CBIs would carry these particular risks—they suggest that we should antici- pate the possibility of altering cognition, mood, or behav- ior when testing new neurological interventions (Glannon 2007).

What Types of Changes Might Occur?

Some changes in cognition, mood, and behavior resulting from CBIs for neurological conditions would, of course, be intended as part of the therapeutic goal. For example, successful treatment of a pediatric metabolic disorder such as Batten disease would entail improvement in cognition and behavior relative to the natural history of the disorder. Similarly, a successful CBI for Alzheimer’s disease would involve improvement of cognition and would prevent or

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delay progression to severe cognitive impairment charac- teristic of later stages of the disease.

Beyond such therapeutic effects, there may be changes that are not sought through the intervention and are not commonly thought of as adverse events, but which nonethe- less raise concerns. A CBI involving implantation of allo- geneic (non-self) cells is a type of transplant, in which the recipient receives donor brain material. This could raise con- cern among some that the recipient might acquire traits of the donor, perhaps even undergoing changes so marked that the recipient becomes almost unrecognizable in affect or cognitive capacity relative to her prior state. (A similar concern has been raised in the context of preclinical stud- ies that involve implanting human-derived neural cells into other animals, raising the specter of creating nonhuman animals with human-like traits (Greene et al. 2005; Karpow- icz et al. 2005; Greely et al. 2007).) The assumption that seems to underlie this concern—one which is generally not well supported by evidence—is that individual brain cells carry the traits we generally associate with entire persons: intelligence, personality, preferences,for example. Research suggests that, notwithstanding contributions from genet- ics (Wright 2005), these higher-order cognitive capacities emerge from networks of cells in the brain, not solely from an individual’s genotype (Pascual-Leone et al. 2005; Sur and Rubenstein 2005). Because transplanted cells will generally be integrated into existing networks of cells, rather than re- constitute entire networks, it seems highly improbable that CBIs will cause recipients to acquire the cognitive character- istics of the cells’ donors. Furthermore, early trials of CBIs are likely to involve non-neuronal cell types that are in- tended to produce missing or otherwise defective proteins or maintain the structural integrity of the CNS (Lazic and Barker 2003; Sanberg et al. 2005). Hence, we believe there is not good reason to expect that the implantation of dis- aggregated cells in the brain could so alter an individual as to make that person unrecognizable to his or her family members or friends.

Nonetheless, grafting cells might influence or modu- late a network of cells in a way that results in more subtle changes in characteristics that the recipient regards as im- portant to his or her sense of self. The extent to which any change is viewed as bearing on this sense of self may vary in individual cases, as different persons attach different levels of significance to their various traits. Moreover, whether a particular change is viewed as desirable or acceptable may depend on an individual’s values and interests. For exam- ple, some aggressive persons might welcome the prospect of becoming more subdued, while others might fear that such a change would make them lose their “competitive edge.”

Another concern is that a particular CBI might lead to a loss in function in parts of the brain, even where the inter- vention is successful in addressing the neurological disorder it is intended to repair. For example, if as a result of the in- tervention, neurons were “rewired” incorrectly, this could lead to the extinction or diminution of previously normal

capacities. Important autobiographical memories could be lost, facts could be forgotten, sexual desire increased or di- minished, or one’s affect altered. Related to such losses of function are a range of “abnormal” functional changes (e.g., seizures, neurogenic pain, dyskinesias), which, though not cognitive or behavioral in nature, could be disabling and problematic for those experiencing them.

Alternatively, a CBI could result in an enhancement, wherein gains in function exceed the therapeutic goal (El- liott 2003; Mehlman 2003; Greely 2006). The mechanism(s) by which such enhancement might be achieved are not clear at this point (Chatterjee 2004). It is not the case, for exam- ple, that increased neural proliferation would necessarily be beneficial. In fact, if not controlled, it is likely to be detri- mental. Under certain conditions, however, it is conceivable that CBIs could modulate or enhance neural networks in a way that promotes more of the “right” kinds of connections between neurons or increased production of the “right” neurotransmitters, so as to have a net beneficial effect on cognition, mood, or behavior.

Importantly, there are at least two different scenarios in which enhancement could occur. The first involves an unin- tended improvement in function beyond expectations. For example, if a CBI for stroke not only repaired brain damage, but actually improved function in a localized region of the brain (e.g., a person’s verbal fluency improved over base- line as a result of the intervention), this would represent an unintended enhancement, since the goal of the therapy was only to reverse damage caused by the stroke. In the second scenario, a CBI is delivered with the explicit intention of improving function above an individual’s normal level of functioning, for example, improving memory or inducing a mood-enhancing effect in an individual with no underlying mood disorder. (A third kind of enhancement might aim at improving aspects of the person’s functioning beyond the normal human range, but this seems likely to remain purely speculative for the foreseeable future.)

This distinction may prove to be artificial. However, we believe it is important to distinguish cases where en- hancement is unintended, but possible, from cases where enhancement is the expressed goal of the intervention. To our knowledge, there are no serious efforts under way to use CBIs specifically to enhance neurological function in persons with no underlying disease or disorder. Regard- less, concerns about intentional enhancement should not determine our thinking about the treatment of serious, of- ten life-threatening neurological conditions in which en- hancement might inadvertently occur. This is not to say that therapies under investigation could not possibly have enhancing effects. But the prospect of such enhancements does not justify constraining a promising line of medical re- search, nor does it justify withholding therapies from those who stand to benefit. (Similarly, the fact that stimulants such as methylphenidate (Ritalin, Novartis Pharmaceuticals) can enhance concentration and attention in healthy individuals does not imply that they should not be used to help indi- viduals with attention deficit hyperactivity disorder.)

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How Could Such Changes Occur?

Predicting the nature or likelihood of any changes in cog- nition, mood, or behavior at the outset of a clinical trial would be almost entirely speculative, but we propose that a number of factors might play influential roles in deter- mining what functional changes might occur with CBIs. Of course, each proposed intervention or therapy is different and should be evaluated in light of its particular character- istics. Still, we believe there are at least five general factors that will be important to consider for all types of interven- tions, and could be profitably compared across interven- tions. First, the genetic source of the cells might prove rele- vant (Silani et al. 2004). Cells from an unrelated donor, for example, might induce changes that autologous cells would not induce. However, as noted previously, to the extent that higher-order brain functions emerge from cell networks— rather than genetic properties of the cells themselves—the source of the cells may be relatively unimportant for influ- encing changes in cognition, mood, or behavior. (The cell source could, however, have a significant adverse influence on the immune response to the transplanted cells.) Second, the timing of the intervention—either the subject/patient’s stage of neurological development or the timing of the inter- vention relative to disease progression, including timing of the intervention relative to the onset of symptoms—might affect the degree to which cells engraft and differentiate in vivo (Escolar et al. 2005; Greene et al. 2005; Regenberg et al. 2008); for example, neonates and children, whose brains are still developing, may experience more substantial integra- tion of introduced cells than may adults with similar levels of neurological damage. Third, the location to which an in- tervention is delivered or targeted would presumably influ- ence the types of changes one might expect to see (Greene et al. 2005). Cells injected in or around the spinal cord, for ex- ample, might result in changes in sensory or motor function (Modo et al. 2002; Keirstead et al. 2005), but not necessar- ily in cognition or behavior. Fourth, the function that cells assume would significantly influence the types of changes anticipated. Glial cells that promote remyelination and re- pair of the spinal cord would likely have different effects than, for example, cells used to repair damaged tissue in the cerebral cortex following stroke (Lindvall and Kokaia 2006). Lastly, the number of cells ultimately generated by the ther- apy, whether it requires one or multiple treatments, i.e., the degree of proliferation (and variables associated with prolif- eration, such as the density of new neural connections or the amount of a given neurotransmitter produced) could influ- ence the magnitude of the changes we might expect (Goh et al. 2003). Overall, one might expect a local therapy in which cells are used as delivery vehicles for growth factors to entail a smaller risk for changes in cognition, mood, or behavior, whereas a global therapy involving cell replacement in the brain may represent a larger risk for such changes.

A WAY FORWARD

That we are unable at present to predict, let alone quantify, all of the risks of CBIs for neurological conditions is neither

reason to discount those risks nor reason to be deterred from responsibly designed and conducted research. But the lack of reliable data is reason to be candid about what is not known, so that as research proceeds, there is a clearer sense of the secondary research questions—most notably whether (and if so, how and to what extent) changes in cognition, mood, or behavior occur as a result of CBIs for neurological conditions.

Precisely because risks cannot be disclosed prospec- tively with adequate precision, potential subjects in studies of these interventions should be informed about the un- certainty that surrounds a broad range of potential unex- pected side effects, including unintended changes in cog- nition, mood, and behavior. What is required is not the rehearsing of a lengthy list of possible effects but rather an explanation that helps potential subjects form a clear understanding that these interventions are still experimen- tal, and that unintended changes could occur and, where appropriate, why in any particular trial there is reason to think that such changes are not expected. Particularly in trials where the subjects have serious neurological condi- tions, it is unlikely that a straightforward disclosure about the uncertainties surrounding possible cognitive or behav- ioral effects would deter many people from volunteering. But even if it did, it is essential to disclose this information in order to obtain valid informed consent.

As trials get under way, it will also be important to collect clinical data that bear on the question of whether changes in cognition, mood, or behavior occur, and if so, the precise nature and magnitude of those changes. We propose that, whenever feasible, subjects should undergo thorough neuropsychological testing before and at appro- priate intervals after the intervention; furthermore, the same data should be collected prospectively on matched control patients, to account for changes that might be otherwise ex- pected (Selnes et al. 2006). A standard battery of diagnostic tests, administered by a clinician skilled in their application, will be important for discerning and quantifying changes in cognition and describing whether or not they are stable after the intervention. Such tests could be augmented by additional instruments, such as the NEO Personality Inven- tory or a similar instrument that measures aspects of per- sonality that are widely held to be stable across an (adult) individual’s lifetime (Costa and McCrae 1992). Admittedly, establishing a meaningful baseline, defined by the subject’s state at the beginning of the trial and prior to treatment, may be complicated when the subjects are infants or children; of course, this is only one of the concerns when including mi- nors in CBI trials (Mathews et al. 2008), and one of many con- cerns in a larger debate about research with minors (Kodish 2005). The results of standardized neuropsychological and personality tests, when available, will provide valuable data on whether and to what extent clinically significant changes occur. Structured interviews with family and close friends of the patient pre- and post-intervention may also help iden- tify perceived affective changes in subjects. Although we realize this information will never conclusively prove that particular types of changes do not or cannot occur, it will

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nevertheless provide a point of reference for what types of changes it may be reasonable to anticipate.

CONCLUSION

Given the small but nonzero risk for unintended changes in cognition, mood, and behavior resulting from CBIs for neu- rological conditions, researchers conducting early human trials should consider the possibility of such changes in the risk-benefit analysis and in the consent process. Data from preclinical studies should be consulted, but are likely to be insufficient for identifying all of the relevant risks. Inves- tigators should disclose the potential risks of unintended changes in neurological function as part of the informed consent process. Human subjects in clinical trials involving such CBIs should be monitored for changes in cognition, mood, and behavior to better identify and quantify these risks. This will require a pre-intervention evaluation as well as post-intervention evaluations at appropriate intervals, to discern whether changes are persistent or whether they resolve or intensify over time. Finally, when reporting re- search results, investigators should include information on adverse events, including any documented changes in cog- nition, mood, and behavior, as well as negative findings (i.e., instances in which no discernable effect is found) to further our understanding of CBIs for neurological conditions, in- cluding their risks and benefits. �

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Predicting Psychological Symptoms: The Role of Perceived Thought Control Ability

Rachel D. Peterson, Jenny Klein, Reesa Donnelly and Kimberly Renk

Department of Psychology, University of Central Florida

Abstract. The suppression of intrusive thoughts, which have been related significantly to depressive and anxious symptoms (Blumberg, 2000), has become an area of interest for those treating individuals with psychological disorders. The current study sought to extend the findings of Luciano, Algarabel, Tomás, and Martı́nez (2005), who developed the Thought Control Ability Questionnaire (TCAQ) and found that scores on this measure were predictive of psychopathology. In particular, this study examined the relationship between scores on the TCAQ and the Personality Assessment Inventory. Findings suggested that individuals’ perceived thought control ability correlated significantly with several dimensions of commonly-occurring psychological symptoms (e.g. anxiety) and more severe and persistent psychological symptoms (e.g. schizophrenia). Regression analyses also showed that perceived thought control ability predicted significantly a range of psychological symptoms over and above individuals’ sex and perceived stress. Findings suggested that thought control ability may be an important future research area in psychological assessment and intervention. Key words: thought control; perceptions; psychological symptoms; personality; thought suppression.

Received 30 June, 2008; Accepted 15 October, 2008

Correspondence address: Kimberly Renk, PhD, Department of Psychology, University of Central Florida, PO Box 161390, Orlando, FL 32816, USA. Tel: +407 823 2218; Fax: +407 823 5862. E-mail: [email protected]

The purposeful attempt to avoid certain thoughts has been termed thought suppression (Wegner, Schneider, Carter, & White, 1987). Although thought suppression is purposeful, research demonstrates that thought suppres- sion is an ineffective coping response for unwanted thoughts (e.g. Page, Locke, & Trio, 2005; Wegner et al., 1987). Given the ineffectiveness of suppressing unwanted thoughts, researchers have examined the relationship between thought suppression and mental health (e.g. Purdon, 1999). An extensive amount of research suggests that higher reliance on thought suppression is related positively to the experience of psycho- logical symptoms (e.g. Abramowitz, Tolin, & Street, 2001), such as those associated with obsessive–compulsive disorder (Purdon, 2004), depression (Dalgleish & Yiend, 2006), borderline personality disorder (Rosenthal,

Cheavens, Lejuez, & Lynch, 2005), alcohol abuse (Klein, 2007), and suicidal ideation (Najmi, Wegner, & Nock, 2007). Although such relationships are being noted, further research is needed to understand fully the relationship between thought suppression and the experience of psychological symptoms.

One issue that needs to be examined is the differing methods of assessing thought sup- pression. One measure, the White Bear Suppression Inventory (WBSI; Wegner & Zanakos, 1994), assesses thought suppression as well as failed suppression attempts, other- wise called intrusive thoughts (Blumberg, 2000; Rassin, 2003). The experience of intru- sive thoughts, which signifies an inability to suppress thoughts effectively, may be related more highly to psychological symptoms than simply the act of thought suppression itself (e.g. Höping & de Jong-Meyer, 2003). In

# 2009 Taylor & Francis ISSN 1650-6073 DOI 10.1080/16506070802561215

Cognitive Behaviour Therapy Vol 38, No 1, pp. 16–28, 2009

support of this hypothesis, research indicates that mere engagement in thought suppression may not provide an accurate prediction of psychological symptoms. An examination of individuals’ perceived ability to control their thoughts suggests that such perceptions may be the predictive mechanism for individuals’ psychological symptoms (Luciano, Algarabel, Tomás, & Martı́nez, 2005), however.

To assess individuals’ perceptions about their ability to control their own thoughts, Luciano et al. (2005) present a self-report measure, referred to as the Thought Control Ability Questionnaire (TCAQ). The TCAQ does not measure individuals’ actual ability to control their thoughts; rather, it taps indivi- duals’ beliefs, or perceptions, of how well they are able to control their thoughts. Therefore, although the measure is called the Thought Control Ability Questionnaire, we refer to the measured variable as perceived thought con- trol ability. Based on the work of Luciano et al. (2005), scores on the TCAQ correlate negatively with WBSI scores, suggesting that the measure has construct validity. In addi- tion, scores on the TCAQ correlate signifi- cantly and negatively with symptoms of depression and anxiety disorders (Luciano et al., 2005). Further, regression analyses demonstrate that scores from the TCAQ account for a significant amount of variance in the experience of similar symptoms after removing variance accounted for by the WBSI (Luciano et al., 2005). Thus, the TCAQ is an important method for assessing individuals’ perceptions about their ability to control their own thoughts over and above their reported use of thought suppression (i.e. individuals’ attempts to avoid/suppress certain thoughts and their experiences of unwanted thoughts). Therefore, if individuals believe that they have highly effective thought control ability (i.e. high scores on the TCAQ), they may be less likely to try to avoid their thoughts (i.e. thought suppression) or experience unwanted intrusive thoughts.

Despite the strong relationship between reported thought control ability, as measured by the TCAQ, and the experience of psycho- logical symptoms, no published research has examined the TCAQ since its initial publica- tion. In particular, several areas deserve atten- tion. First, the TCAQ was created and validated in Spanish. Although there is a

translated and published English version, its reliability has not been assessed. Second, Luciano et al. (2005) provide statistical ana- lyses that were conducted with a combined group of men and women. Research utilizing the WBSI indicates, however, that women are more likely to rely on thought suppression than men (e.g. Wegner & Zanakos, 1994). Further, a review comparing men and women on experi- enced and reported emotionality suggests that women are more likely to ruminate and report the experience of emotions than men (Robinson & Clore, 2002). If women are more likely to suppress their thoughts and to experience negative ruminations, they may be less likely to perceive control over their thoughts. Thus, the relationship between per- ceptions of thought control ability and psy- chological symptoms should be examined separately for men and women.

Third, the original regression analyses for the TCAQ did not account for the stress that participants may have been experiencing. Given that thought suppression is less effective during times of stress (Wegner, 1994; Wenzlaff & Wegner, 2000), thought control ability also may be affected negatively by stress. Moreover, stress is related to the experience of many forms of psychological symptoms (e.g. Bogler, DeLongis, Kessler, & Schilling, 1989; Felsten, 2004). Thus, it is important to examine stress in the relationship between perceived thought control ability and psychological symptoms to ensure that stress does not account for increased symptoms when the perceived ability to control thoughts may be decreased.

Finally, in the original study of the TCAQ, the outcome variables are limited to depres- sive and anxious symptoms, with no other research examining the relationship between perceived thought control and other types of psychological symptoms. Supporting research can be found in the related thought suppres- sion literature, however, which suggests that thought control may be related to symptoms of borderline personality disorder, anxiety disorders, alcohol abuse, and suicidal ideation (Dalgleish & Yiend, 2006; Klein, 2007; Najmi et al., 2007; Purdon, 2004; Rosenthal et al., 2005). Further, based on the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision [DSM-IV-TR]) criteria for other disorders, individuals experiencing symptoms of schizophrenia and mania may

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experience unwanted intrusive thoughts in the form of paranoia, delusions, grandiosity, or racing thoughts (American Psychological Association, 2000). Although these findings are suggestive, the relationship between thought control ability and other psychological symptoms, such as those consistent with borderline personality disorder, somatization, substance abuse, suicidal ideation, schizophre- nia, and mania, has yet to be investigated. Thus, the relationship between individuals’ perceptions of thought control ability and their experience of a variety of psychological symp- toms deserves further study.

Given these identified limitations to the previous examination of the TCAQ, the current study seeks to extend previous research by (1) examining the reliability of the English version of the TCAQ with a primarily English-speaking sample, (2) asses- sing male and female participants separately to explore potential sex differences, (3) deter- mining whether the TCAQ is predictive of psychological symptoms after accounting for perceived stress, and (4) examining a wide range of psychological symptom profiles using a well-validated measure (i.e. the Personality Assessment Inventory [PAI]; Morey, 1991). Consistent with previous research, it is hypothesized that the TCAQ will demonstrate adequate internal consistency and that men will report higher levels of perceived thought control ability than women.

Although previous research has examined the relationship between thought suppression and psychological symptoms, research needs to further examine the relationship between perceived thought control and psychological symptoms. Based on previous research exam- ining thought suppression as well as diagnos- tic symptoms included for different disorders in the DSM-IV-TR, the TCAQ is expected to predict significantly depressive and anxious symptoms as well as other symptoms, such as those seen with somatization disorder, borderline personality disorder, schizophre- nia (including the paranoid clinical scale), mania, substance abuse, and suicidal ideation, after accounting for the predictive nature of perceived stress. In particular, with the experience of each of these categories of symptoms, it is anticipated that individuals will experience rumination and difficulty controlling unwanted thoughts. In contrast,

it is anticipated that perceived thought control ability will not be related to features consis- tent with antisocial personality disorder, because such diagnostic symptoms do not include the experience of unwanted thoughts (American Psychological Association, 2000).

The PAI also includes treatment-related scales that have not been examined previously in the context of their relationship with thought control ability, with the exception of suicidal ideation. Therefore, analyses regard- ing the relationship between perceived thought control and three treatment-related subscales (i.e. stress, nonsupport, and treat- ment rejection) are considered exploratory; as a result, appropriate statistical considerations were made. It is anticipated, however, that increased perceptions of thought control ability will be related to decreased levels of stress and nonsupport as well as to increased levels of treatment rejection (because indivi- duals may believe that treatment is unneces- sary if they are not experiencing unwanted thoughts).

Method Participants Participants were 499 undergraduate students at a large Southeastern university in the United States. Of these, 283 individuals (233 women and 50 men) provided complete information (see Validity Considerations section). As part of demographics questions, participants were asked to select one category that identified their age grouping. The frequencies of responses provided per category are as follows: 186 participants (65.7%) were in the 18 to 19- year age range; 56 (19.8%) in the 20 to 21-year range; 18 (6.4%) in the 22 to 23-year range; seven (2.5%) in the 24 to 25-year range; five (1.8%) in the 26 to 28-year range; six (2.1%) in the 29 to 33-year range; two (0.7%) in the 34 to 39-year range; and two (0.7%) in the 40-year and older range; one (0.3%) participant did not respond. The majority of the female partici- pants (n5164 [70.3%]) self-identified as Caucasian; 12 (5.2%) identified as Black, 12 (5.2%) as Asian, two (0.8%) as Indian, nine (3.9%) as biracial, and 34 (14.6%) as ‘‘other.’’ Men also varied in their race self-identification: 36 (72%) Caucasian, three (6%) Black, three (6%) Asian, two (4%) biracial, and six (12%) ‘‘other.’’

18 Peterson, Klein, Donnelly, and Renk COGNITIVE BEHAVIOUR THERAPY

Measures Demographic information. Participants were asked to complete a series of brief questions regarding their demographic information, such as their age, race, and ethnic origin. Thought control ability. The 25-item TCAQ (Luciano et al., 2005) was used to assess participants’ perceived ability to control their own thoughts. Participants responded to statements (e.g. ‘‘I can manage to have control over my thoughts even when under stress’’) using a Likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). Scores may range between 25 and 125, with higher scores indicating that individuals perceive themselves to be better able to control their own thoughts. The TCAQ included one factor with a Cronbach’s alpha coefficient of .92 and a test–retest reliability of .88 after 2 months (Luciano et al., 2005). Psychological symptoms. The 344-item PAI (Morey, 1991) assesses the manifestation of clinical syndromes based on the current diagnostic classifications of mental disorders. Participants rated each statement (e.g. ‘‘I hardly have any energy’’) on a scale ranging from 1 (false) to 4 (very true). This measure yields several scores, including 11 main clinical syndrome scales, 28 clinical syndrome subscales, five treatment consideration scales, and two interpersonal scales.

The PAI main clinical syndrome scales are as follows: Somatic Complaints (SOM), Anxiety (ANX), Anxiety-Related Disorders (ARD), Depression (DEP), Mania (MAN), Paranoia (PAR), Schizophrenia (SCZ), Drug Problems (DRG), Alcohol Problems (ALC), and two scales that assess features of Borderline (BOR) and Antisocial (ANT) Personality Disorders. For each main clinical syndrome scale, at least three related subscales also can be derived. These clinical syndrome subscales provide information regarding symptom-specific components of the main clinical syndromes. The 28 clinical syndrome subscales corresponding to each respective main clinical syndrome scale are as follows: Conversion (SOM-C), Somatization (SOM- S), Health Concerns (SOM-H), Cognitive Anxiety (ANX-C), Affective Anxiety (ANX-A), Physiological Anxiety (ANX-P), Obsessive– Compulsion (ARD-O), Phobias (ARD-P), Traumatic Stress (ARD-T), Cognitive Depression (DEP-C), Affective Depression

(DEP-A), Physiological Depression (DEP-P), Activity Level (MAN-A), Grandiosity (MAN-G), Irritability (MAN-I), Hypervigi- lance (PAR-H), Persecution (PAR-P), Re- sentment (PAR-R), Psychotic Experiences (SCZ-P), Social Detachment (SCZ-S), Thought Disorder (SCZ-T), Affective Instability (BOR- A), Identity Problems (BOR-I), Negative Relationships (BOR-N), Self-Harm (BOR- S), Antisocial Behaviors (ANT-A), Egocen- tricity (ANT-E), and Stimulus-Seeking (ANT-S). The PAI also provides treatment consideration scales and four are considered here: Suicidal Ideation (SUI), Stress (STR), Nonsupport (NON), and Treatment Rejection (RXR). T scores on these scales have a mean of 50 (SD510), and those scores reaching at least 2 SDs above the mean (i.e. T>70) represent pronounced, or clinically significant, difficulties in the areas identified compared with the typical responses of a community sample.

The PAI was designed with a specific focus on construct validity and has reasonable to good internal consistency and test–retest relia- bility. See Morey (1991, 2004, 2006) for more detailed discussions. In this study, Cronbach alpha coefficients ranged from .67 to .90 for main clinical syndrome scales, from .37 to .85 for clinical syndrome subscales, and from .69 to .86 for treatment consideration scales. For the six clinical syndrome subscales that yielded comparatively low internal consistency reli- abilities (i.e. av.60), a closer examination of the items loading on each scale indicated that the questions may have assessed symptoms related to more than one construct. For example, the low alpha coefficient for the ARD-P (.50) subscale may be expected when considering that the item content assesses for phobias or fears related to specific situations (e.g. presenting in front of others, heights, driving on freeways, and riding in airplanes). That is, an individual may experience extreme anxiety, or a phobic response, in reaction to one type of situation, but not necessarily all those assessed by this subscale. Given the comparatively low internal consistency of these subscales, they should be interpreted with caution.

Procedure Participants were directed to a secure website for data collection where they were presented

VOL 38, NO 1, 2009 Predicting PAI scores 19

with a list of ongoing studies available for participation. All individuals had the oppor- tunity to select whichever study they desired; descriptions of each were provided. Those who participated in this online study provided an informed consent form first and subse- quently completed the above-mentioned mea- sures in a web-based format. After com- pleting the measures, participants were shown a debriefing statement, which explained the purpose of the study and provided contact information for the researchers. All partici- pants, including those who did not complete their surveys fully, were provided with extra credit points to be used toward a psychology course as compensation.

Validity considerations Several validity checks were included in this study to address potential random responding and other invalid response patterns that may have occurred as a result of the web-based structure of the study. First, participants who discontinued early were not included in the analyses (n540). It should be noted that some participants may have been forced to discon- tinue participation because of technical pro- blems (e.g. Internet difficulties). These individuals may have restarted and completed the study as a ‘‘new’’ participant, meaning that their originally incomplete data were excluded but their ultimately completed sur- veys were retained in the sample. Second, to address possible random endorsements, six validity-check items (e.g. ‘‘Select number 3 for this item, corresponding to agree and disagree equally’’) were added throughout the series of questions. Participants who answered at least one of these incorrectly were not included in the analyses (n575). Finally, the PAI provides subscales that identify participants whose endorsements suggest uninterpretable patterns of information (e.g. inconsistency, positive impression management, and negative impres- sion management). If participants demon- strated such patterns, they also were not included in the analyses (i.e. 101 excluded). In sum, 216 initial participants were not included in the analyses because of their failure to pass these validity criteria. Possible differences between included and excluded participants on demographic variables are discussed next in the Results section.

Results Comparing excluded and included participants Chi-square analyses were used to examine potential differences in the demographic vari- ables between the included and excluded participants. No significant differences in age, x2(7, N5479)58.61, pv.28, or race, x2(6, N5480)512.29, pv.06, were found. Participants who were included were more likely to be female, x2(1, N5480)55.51, pv.02. Because the majority of the participants in the original sample were female, this finding is not surprising. Further comparisons of differences in reports of psychological symptoms could not be conducted because of the incomplete data provided by the excluded portion of the sample. Therefore, it is impossible to determine whether differences exist between these sam- ples in their PAI scores.

Descriptive statistics Descriptive statistics further indicated that all PAI scale means fell near or at the expected nonclinical level (i.e. ,T550). A number of participants, however, endorsed symptoms within the clinically significant range. For example, 8.5% and 7.1% of female partici- pants endorsed clinically significant levels of ANX and BOR symptoms, respectively. For men, 6% endorsed clinically significant levels of MAN and ANT features, respectively (note that Morey’s, 1991, suggested cut-offs for these scales are higher for this age group than in the general population).

Reliability of the TCAQ The Cronbach alpha internal consistency reliability coefficients for the current sample (i.e. male5.89, female5.91) using the English version of the TCAQ were similar to the previously published reliability coefficients for the Spanish version (Luciano et al., 2005).

Scores for male versus female participants Because of unequal sample sizes of male and female participants, a random sampling of 50 female participants was used to compare male and female participants’ TCAQ scores using an independent-samples t test. This result revealed that male participants (M582.43, SD513.97) reported significantly higher levels

20 Peterson, Klein, Donnelly, and Renk COGNITIVE BEHAVIOUR THERAPY

of perceived thought control ability compared with the sampled group of female participants (M573.54, SD515.01), t(46)52.96, pv.004. Thus, both male and female participants similarly reported moderate levels of thought control ability.

Two-tailed Pearson product–moment cor- relations also were computed separately for male versus female (i.e. the complete set) participants using the TCAQ total score and the scores on the PAI main clinical syndrome, treatment consideration, and interpersonal scales. To account for the large number of correlations calculated, alpha levels were adjusted using Bonferroni corrections and are reported accordingly in the tables. For male participants, TCAQ scores demonstrated significant negative correlations with five of the 11 main clinical syndrome scales (i.e. ANX, DEP, PAR, SCZ, and BOR) and with three of four treatment consideration scales (i.e. SUI, NON, and RXR). In contrast, there was a significant positive correlation between TCAQ scores and the RXR treatment scale. The correlations generally were quite strong (i.e. ranging up to 2.80). Thus, higher levels of perceived thought control ability were related significantly to lower levels of ANX, DEP, PAR, SCZ, and BOR symptoms as well as to lower levels of SUI and NON. In contrast, higher levels of perceived thought control ability were related significantly to higher levels of RXR (see Table 1). To

examine more closely these relationships for men, two-tailed Pearson product–moment correlations were computed between the TCAQ total score and the clinical syndrome subscales of those overall clinical syndrome scales that demonstrated significant relation- ships (see Table 2). Each clinical syndrome subscale cluster demonstrated at least one significant relationship with perceived thought control ability. The ANX and DEP scale clusters were the only clusters for which all subscales were correlated significantly with the TCAQ, whereas the relationships of other clinical subscales varied.

For female participants, the TCAQ total score demonstrated significant negative corre- lations with eight of the 11 main clinical syndrome scales (i.e. with the exceptions of ANT, ALC, and DRG) and all four treatment consideration scales. Only RXR demonstrated a positive correlation with the TCAQ. Again, correlations were strong, ranging as high as 2.73. Thus, higher levels of perceived thought control ability were related significantly to lower levels of SOM, ANX, ARD, DEP, MAN, PAR, SCZ, and BOR symptoms as well as to lower levels of SUI, STR, and NON. In contrast, higher levels of perceived thought control ability were related signifi- cantly to higher levels of RXR (see Table 1). Two-tailed Pearson product–moment correla- tions also were computed between the TCAQ total score and the clinical syndrome subscales

Table 1. Correlations between Thought Control Ability Questionnaire scores and Personality Assessment Inventory clinical syndrome, treatment consideration, and interpersonal scales by sex

Variable

PAI clinical syndrome scales

SOM ANX ARD DEP MAN PAR SCZ DRG ALC BOR ANT

Men 2.37 2.68* 2.37 2.80* .14 2.43* 2.66* 2.19 2.01 2.71* .19

Women 2.38* 2.73* 2.66* 2.62* 2.19* 2.52* 2.55* 2.08 2.07 2.64* .06

Variable PAI treatment consideration and interpersonal scales

SUI STR NON RXR

Men 2.46* 2.29 2.51* .60*

Women 2.34* 2.35* 2.36* .53*

Note. PAI5Personality Assessment Inventory; SOM5Somatic Complaints; ANX5Anxiety; ARD5Anxiety- Related Disorders; DEP5Depression; MAN5Mania; PA5Paranoia; SCZ5Schizophrenia; DRG5Drug Problems; ALC5Alcohol Problems; BOR5Borderline Personality Disorder; ANT5Antisocial Personality Disorder; SUI5Suicidal Ideation; STR5Stress; NON5Nonsupport; RXR5Treatment Rejection. *pv.003, based on Bonferroni-adjusted alpha levels.

VOL 38, NO 1, 2009 Predicting PAI scores 21

of those overall clinical syndrome scales that demonstrated significant relationships. Analyses revealed that all entered subscales were correlated significantly and negatively with female participants’ perceived ability to control their thoughts (see Table 2).

Predicting psychological symptoms Hierarchical multiple regression analyses were conducted to determine the extent to which participants’ perceived ability to control their thoughts predicted their reported levels of psychological symptoms, beyond the variance accounted for by stress independently. These regression analyses only were conducted when correlations indicated a significant relation- ship between both predictors (i.e. STR and TCAQ total score) and the clinical syndrome scale scores. Further, only main clinical syndrome scales were included as dependent variables in these regression analyses to control for experimentwise error rates. These regression analyses were completed separately for male and female participants (given the differential relationships for male and female participants described previously). Both male

and female participants’ perceived ability to control their own thoughts predicted signifi- cantly all the clinical scale scores that were examined after accounting for STR, with the exceptions of MAN for female participants (i.e. this regression only approached signifi- cance; see Tables 3 and 4).

Discussion Reliability and demographic findings Consistent with the hypotheses for this study, the English language version of the TCAQ demonstrates adequate internal consistency (Luciano et al., 2005), and male participants report significantly higher perceptions of their thought control ability relative to female participants (Wegner & Zanakos, 1994). Such sex differences may reflect an uneven societal pressure on men to remain in control of their thoughts relative to the higher social acceptability for women to experience and express emotion (Robinson & Clore, 2002). Robinson and Clore (2002) also suggest that women are more likely to ruminate about negative experiences than are men. Further, if

Table 2. Correlations between Thought Control Ability Questionnaire scores and Personality Assessment Inventory clinical syndrome subscales by sex

PAI clinical syndrome subscales

Sex SOM-C SOM-S SOM-H ANX-C ANX-A ANX-P ARD-O ARD-Pa ARD-T

Male 2.15 2.41* 2.22 2.65* 2.62* 2.54* .09 2.40* 2.47*

Female 2.26* 2.41* 2.27* 2.72* 2.64* 2.58* 2.27* 2.48* 2.62*

DEP-C DEP-A DEP-P MAN-Aa MAN-G MAN-I PAR-H PAR-P PAR-R

Male 2.79* 2.72* 2.51* 2.28 .47* 2.11 2.29 2.14 2.60*

Female 2.53* 2.58* 2.49* 2.31* .22* 2.35* 2.43* 2.29* 2.48*

SCZ-P SCZ-S SCZ-T BOR-A BOR-I BOR-Na BOR-Sa

Male 2.19 2.54* 2.61* 2.63* 2.67* 2.52* 2.24

Female 2.32* 2.27* 2.55* 2.60* 2.56* 2.53* 2.14*

Note. PAI5Personality Assessment Inventory; SOM5Somatic Complaints (C5Conversion, S5Somatization, H5Health Concerns); ANX5Anxiety (C5Cognitive Anxiety, A5Affective Anxiety, P5Physiological Anxiety); ARD5Anxiety-Related Disorders (O5Obsessive–Compulsion, P5Phobias, T5Traumatic Stress); DEP5Depression (C5Cognitive Depression, A5Affective Depression, P5Physiological Depression); MAN5Mania (A5Activity Level, G5Grandiosity, I5Irritability); PAR5Paranoia (H5Hypervigilance, P5Persecution, R5Resentment); SCZ5Schizophrenia (P5Psychotic Experiences, S5Social Detachment, T5Thought Disorder); BOR5Borderline Personality Disorder (A5Affective Instability, I5Identity Problems, N5Negative Relationships, S5Self-Harm). aLow internal consistency (av.60). *pv.002, based on Bonferroni-adjusted alpha levels.

22 Peterson, Klein, Donnelly, and Renk COGNITIVE BEHAVIOUR THERAPY

women are more likely to attempt thought suppression (Wegner & Zanakos, 1994), their inability to control their thoughts may be a

consequence of failed attempts at suppression. Thus, the findings of this study are consistent with those of previous research.

Table 3. Hierarchical regressions for males: thought control ability predicts clinical scale scores on the Personality Assessment Inventory (PAI) after accounting for stress

Predicted variable B b R2 DR2 F(df) DF(df)

SOM Step 1: STR .27 .39 .15 .15*** 8.12(1, 45) N/A Step 2: .22 .07** 6.35(2, 44) 4.03(1, 44) (STR) .22 .31 TCAQ 2.10 2.28

ANX Step 1: STR .34 .37 .14 .14** 7.02(1, 45) N/A Step 2: .50 .36*** 21.60(2, 44) 31.44(1, 44) (STR) .17 .18 TCAQ 2.30 2.63

ARD Step 1: STR .15 .12 .02 .02 0.67(1, 45) N/A Step 2: .14 .12** 3.50(2, 44) 6.26(1, 44) (STR) .02 .01 TCAQ 2.23 2.37

DEP Step 1: STR .45 .35 .12 .12** 6.28(1, 45) N/A Step 2: .65 .53*** 40.57(2, 44) 65.81(1, 44) (STR) .16 .13 TCAQ 2.50 2.76

PAR Step 1: STR .46 .34 .11 .11** 5.68(1, 45) N/A Step 2: .23 .12** 6.65(2, 44) 6.89(1, 44) (STR) .32 .23 TCAQ 2.26 2.36

BOR Step 1: STR .56 .49 .24 .24*** 14.52(1, 45) N/A Step 2: .59 .35*** 31.98(2, 44) 37.63(1, 44) (STR) .35 .31 TCAQ 2.36 2.62

SUI Step 1: STR .23 .23 .05 .05 2.50(1, 45) N/A Step 2: .22 .17*** 6.20(2, 44) 9.48(1, 44) (STR) .10 .10 TCAQ 2.22 2.43

SCZ Step 1: STR .32 .26 .07 .07* 3.23(1, 45) N/A Step 2: .44 .37*** 17.28(2, 44) 29.30(1, 44) (STR) .09 .07 TCAQ 2.40 2.64

Note. Predictor variables include STR from the PAI and the TCAQ. The mean score on the TCAQ was 82.4 (SD513.97), N547. SOM5Somatic Complaints; STR5Stress; TCAQ5Thought Control Ability Questionnaire; ANX5Anxiety; ARD5Anxiety-Related Disorders; DEP5Depression; PAR5Paranoia; SCZ5Schizophrenia; BOR5Borderline Personality Disorder; SUI5Suicidal Ideation; N/A5not applicable. *pv.10. **pv.05. ***pv.01.

VOL 38, NO 1, 2009 Predicting PAI scores 23

Table 4. Hierarchical regressions for females: thought control ability predicts clinical scale scores on the Personality Assessment Inventory (PAI) after accounting for stress

Predicted variable B b R2 DR2 F(df) DF(df)

SOM Step 1: STR .34 .35 .12 .12*** 29.60(1, 217) N/A Step 2: .19 .07*** 26.05(2, 216) 19.92(1, 216) (STR) .24 .25 TCAQ 2.16 2.29

ANX Step 1: STR .45 .36 .13 .13*** 32.16(1.217) N/A Step 2: .54 .41*** 127.39(2, 216) 194.01(1, 216) (STR) .15 .12 TCAQ 2.48 2.68

ARD Step 1: STR .37 .31 .10 .10*** 22.94(1, 217) N/A Step 2: .44 .34*** 83.71(2, 216) 130.76(1, 216) (STR) .11 .10 TCAQ 2.41 2.62

DEP Step 1: STR .48 .42 .18 .18*** 47.52(1, 217) N/A Step 2: .44 .26*** 83.03(2, 216) 97.43(1, 216) (STR) .27 .24 TCAQ 2.34 2.54

PAR Step 1: STR .43 .40 .16 .16*** 40.60(1, 217) N/A Step 2: .33 .17*** 52.13(2, 216) 53.78(1, 216) (STR) .26 .25 TCAQ 2.26 2.44

BOR Step 1: STR .49 .45 .20 .20*** 53.89(1, 217) N/A Step 2: .46 .26*** 93.03(2, 216) 106.08(1, 216) (STR) .28 .26 TCAQ 2.34 2.55

SUI Step 1: STR .18 .19 .03 .03*** 7.70(1, 217) N/A Step 2: .12 .09*** 15.00(2, 216) 21.58(1, 216) (STR) .08 .08 TCAQ 2.18 2.32

SCZ Step 1: STR .33 .34 .12 .12*** 29.16(1, 217) N/A Step 2: .33 .21*** 52.25(2, 216) 66.53(1, 216) (STR) .17 .18 TCAQ 2.26 2.49

MAN Step 1: STR .20 .20 .04 .04*** 9.32(1, 217) N/A Step 2: .06 .02* 6.44(2, 216) 3.46(1, 216) (STR) .16 .16 TCAQ 2.07 2.13

Note. Predictor variables include STR from the PAI and the TCAQ. The mean score on the TCAQ was 77.8 (SD515.03), N5219. SOM5Somatic Complaints; STR5Stress; TCAQ5Thought Control Ability Questionnaire; ANX5Anxiety; ARD5Anxiety-Related Disorders; DEP5Depression; MAN5Mania; PAR5Paranoia; SCZ5Schizophrenia; BOR5Borderline Personality Disorder; SUI5Suicidal Ideation; N/A5not applicable. *pv.10. ***pv.01.

24 Peterson, Klein, Donnelly, and Renk COGNITIVE BEHAVIOUR THERAPY

Perceived thought control ability and main clinical syndrome scales For all scales, scores on the PAI were consistent with the community-based nature of the sample (Morey, 1991). As expected, for both the male and female participants in this study, almost all the main clinical syndrome scale scores were correlated significantly with perceptions of their thought control ability. Not only did participants’ perceptions regard- ing their thought control ability relate to previously established psychological symp- toms (Luciano et al., 2005), but these percep- tions also were related to psychological symptoms that would be considered more severe and pervasive. In addition, despite symptoms consistent with borderline person- ality disorder being exhibited more commonly by women, a significant relationship between these symptoms and the perceived thought control ability of the male participants in this study was found as well. For both sexes, it appeared that decreased perceptions of the ability to control internal thought patterns related with individuals’ higher inability to regulate their emotions.

One interesting finding for all participants was the lack of significant correlations between their perceived thought control abil- ity and their endorsements of drug and alcohol use. A lack of significant correlations between these factors is somewhat surprising given that previous research indicates a link between the avoidance of negative feelings, an inability to control anxiety, and substance abuse disorders (Forsyth, Parker, & Finlay, 2003). One possible explanation may be that cognitive control represents a factor that is quite different from physical behavior, and many individuals may experience low insight into the relationship between their thoughts and behaviors. Another way to view this finding is to consider drug and alcohol use as a form of behavioral avoidance of the experience of negative or distressing emotions. By this definition, a correlation may not be expected because these avoidant behaviors may, in a sense, be reported in the place of endorsements of psychological symptoms, as respondents may deny experiencing any distressing emotions. Also, given the considerable normalization of these behaviors in the college environment (e.g. Perkins, Haines, & Rice, 2005), students may have

underestimated the extent to which their alcohol and drug use is problematic. Further, the TCAQ appears more related with internalizing disorders and, as a result, may not show strong relationships with substance abuse, which is considered to be more of an externalizing disorder (Krueger et al., 2002).

Perceived thought control ability and clinical syndrome subscales There were some interesting findings related to the clinical syndrome subscales. At times, the relationships between the TCAQ and symptom cluster subscales are consistent (e.g. DEP). Within other symptom clusters (e.g. BOR), the relationships with perceived thought control ability differ. With the BOR cluster in men, three of four subscales are correlated signifi- cantly with the TCAQ, whereas the BOR-S subscale is not correlated significantly. Overall, such differential relationships may indicate that there are underlying patterns for each symptom category regarding the importance of thought control ability.

Perceived thought control ability and treatment consideration There also was a positive and significant correlation between individuals’ perceived ability to control their thoughts and RXR. Conceivably, individuals’ beliefs about their thought control ability may not accurately reflect their objective ability to control their thoughts. Thus, they may be more resistant to therapeutic intervention because of a lack of insight regarding the potential need for therapy. As individuals’ perception of their ability to control their thoughts increases, they also report fewer symptoms. Thus, an increased tendency to reject treatment only may be important to those individuals who are experiencing greater levels of symptoms and, thus, who are in greater need of therapeutic intervention.

Stress and perceived thought control ability: predictive relationships In addition to the correlational relationships between perceived thought control ability and psychological symptoms in this study, the utility of perceived thought control ability in predicting psychological symptoms also was examined. As expected, after first removing

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the variance accounted for by stress, perceived thought control ability additionally accounted for a significant portion of the variance across several domains of psychological symptoms. These findings suggest that individuals’ beliefs regarding their ability to control their own thoughts are predictive of the existence of psychological symptoms, even beyond the variance accounted for by stress alone. Although research suggests that thought sup- pression is not an adaptive form of coping (Muris, De Jongh, & Merckelbach, 1998), it is unclear what drives the inverse relationship between stress and thought control ability. It may be that individuals’ belief in their ability to control their thoughts represents a form of psychological coping, which may result in a subsequent reduction in stress. Conversely, it may be that stress reduces the ability to control thoughts. These underlying mechanisms will need to be explored in future research.

Implications The implications of this self-report of perceived thought control may be far-reaching. The TCAQ score predicts the endorsement of psychological symptoms, even beyond the impact of stress. Therefore, therapeutic inter- ventions aimed at enhancing individuals’ per- ceptions of their ability to control their own thoughts (i.e. a form of cognitive empower- ment) will need to be explored as a means for decreasing psychological symptoms more effectively, particularly within the context of cognitively-based strategies. Specifically, it may be that, by enhancing individuals’ ability to accurately perceive their ability to control their thoughts or the effectiveness with which they control their thought processes, they may, in turn, be able to incorporate interventions geared at improving their actual ability to do so. Also, the TCAQ could be used potentially as a primary screening tool for choosing intervention approaches. It may be that those who score highly may benefit most from cognitive behavioral interventions, whereas those who report low scores may be best suited to undergo a mindfulness- or acceptance-based intervention. This possibility would need to be explored in future research.

Limitations Limitations of the current study result primarily from the sample. Although a percentage of

the participants were excluded from the analyses as a result of validity concerns, this lengthy screening process allowed researchers to ensure that the utilized data were valid. In particular, participants had to answer cor- rectly validity questions that were embedded throughout the survey and to demonstrate a valid profile on the PAI. Further, it must be noted that the population sampled in this study consisted of a group of nonclinical college students. Therefore, the responses of this sample may be different from those of other groups of individuals. The TCAQ should, therefore, be validated using other community-based and clinic-referred samples. In addition, the fact that only two self-report measures were examined limits the scope of the results; therefore, future studies using these scales should include additional mea- sures of related constructs.

pAnother limitation of this study is the cross-sectional and single-point-in-time mea- surement design, which may not address the developmental aspects of the perception of thought control ability. Longitudinal studies incorporating experimental designs may be helpful in elucidating these confounding factors. Further, the comparatively low internal consistency reliability found for six PAI clinical syndrome subscales should be inter reted with caution, in contrast with all other scales, which yielded adequate alpha coefficients of reliability. Finally, although our selection of predictor and criterion variables used in the regression analyses was theoretically-based, the directionality of the relationships between perceptions of thought control ability and psychological symptoms may vary depending on the particular symptom constellations examined. Thus, it cannot be assumed that individuals’ decreased ability to control their thoughts leads to psychological symptoms. The reverse may be true, such that individuals who are experiencing psychological difficulties may have a reduced ability to control thoughts.

Future directions Future investigations of the nature and impact of individuals’ perceptions of thought control ability are countless, because this area is new and exciting and has only recently begun to receive attention. Future research should examine a community sample. Further, other

26 Peterson, Klein, Donnelly, and Renk COGNITIVE BEHAVIOUR THERAPY

investigations should examine models that identify causal relationships between percep- tions of thought control and psychological symptoms. By examining such models, a better understanding of whether perceptions of thought control ability precede the devel- opment of certain symptoms, or vice versa, could be gained. Further, experimental designs assessing individuals’ objective abil- ities to assert control over their thoughts may provide information regarding the relation- ship between true thought control ability and related psychological symptoms.

In summary, the hypotheses regarding the relationships between individuals’ perceptions of their ability to control their own thoughts and several dimensions of psychological symptoms are supported. In addition, for both male and female participants, perceived thought control ability is significantly pre- dictive of many domains of psychological symptoms, beyond the variance accounted for by stress. Therefore, it is clear that indivi- duals’ perceptions regarding their ability to control their own thoughts is a particularly important factor in the experience of psycho- logical symptoms and should be studied in future research in the context of psychological evaluations and therapeutic interventions.

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