The latent structure of posttraumatic stress disorder: A taxometric investigation of reactions to extreme stress.

Mental health professionals have debated whether posttraumatic stress disorder (PTSD) can be qualitatively distinguished from normal reactions to traumatic events. This debate has been fueled by indications that many trauma-exposed individuals evidence partial presentations of PTSD that are associated with significant impairment and help-seeking behavior. The authors examined the latent structure of PTSD in a large sample of male combat veterans. Three taxometric procedures--MAMBAC, MAXEIG, and L-Mode--were performed with 3 indicator sets drawn from a clinical interview and a self-report measure of PTSD. Results across procedures, consistency tests, and analysis of simulated comparison data all converged on a dimensional solution, suggesting that PTSD reflects the upper end of a stress-response continuum rather than a discrete clinical syndrome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A taxometric analysis of the latent structure of psychopathy: Evidence for dimensionality.

The taxonomic status of psychopathy is controversial. Whereas some studies have found evidence that psychopathy, at least its antisocial component, is distributed as a taxon, others have found that both major components of psychopathy-callousness/unemotionality and impulsivity/antisocial behavior-appear to distribute as dimensions and show little evidence of taxonicity. In the present study, recent advances in taxometric analysis were added to P. Meehl's (1995) multiple consistency tests strategy for assessing taxonicity, and they were applied to Psychopathy Checklist-Revised (R. D. Hare, 2003) ratings of 4,865 offenders sampled from multiple forensic settings. The results indicated that both the individual components of psychopathy and their interface are distributed dimensionally. Both the implications of these results for research in psychopathy and the integration of these findings with previous taxometric studies of psychopathy are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Latent structure of the alexithymia construct: A taxometric investigation.

Despite a wealth of research on the validity of alexithymia and its association with a number of common medical and psychiatric disorders, the fundamental question of whether alexithymia is best conceptualized as a dimensional or categorical construct remains unresolved. In the current investigation, taxometric analysis is used to examine the nature of the latent structure of alexithymia. Several nonredundant taxometric procedures were performed with item sets from the 20-item Toronto Alexithymia Scale (R. M. Bagby, J. D. A. Parker, & G. J. Taylor, 1994) as indicators. These procedures were applied separately in large community (n = 1,933) and undergraduate (n = 1,948) samples and in a smaller sample of psychiatric outpatients (n = 302). The results across various taxometric procedures and the different samples provide strong support that alexithymia is a dimensional construct. Some theoretical implications of these findings for research on the alexithymia construct are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A taxometric study of the latent structure of disgust sensitivity: Converging evidence for dimensionality.

Disgust sensitivity has recently been implicated as a specific vulnerability factor for several anxiety-related disorders. However, it is not clear whether disgust sensitivity is a dimensional or categorical phenomenon. The present study examined the latent structure of disgust by applying three taxometric procedures (maximum eigenvalue, mean above minus below a cut, and latent-mode factor analysis) to data collected from 2 large nonclinical samples on 2 different measures of disgust sensitivity. Disgust sensitivity in the first sample (n=1,153) was operationalized by disgust reactions to food, animals, body products, sex, body envelope violations, death, hygiene, and sympathetic magic, as assessed by the Disgust Sensitivity Scale (J. Haidt, C. McCauley, & P. Rozin, 1994). Disgust Sensitivity Scale indicators of core, animal reminder, and contamination disgust were also examined in the 1st sample. Disgust sensitivity in the 2nd independent sample (n=1,318) was operationalized by disgust reactions to animals, injections and blood draws, mutilation and death, rotting foods, and odors, as assessed by the Disgust Emotion Scale (R. A. Kleinknecht, E. E. Kleinknecht, & R. M. Thorndike, 1997). Results across both samples provide converging evidence that disgust sensitivity is best conceptualized as a dimensional construct, present to a greater or lesser extent in all individuals. These findings are discussed in relation to the conceptualization and assessment of disgust sensitivity as a specific dimensional vulnerability for certain anxiety and related disorders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A taxometric analysis of actual internet sports gambling behavior.

This article presents findings from the first taxometric study of actual gambling behavior to determine whether we can represent the characteristics of extreme gambling as qualitatively distinct (i.e., taxonic) or as a point along a dimension. We analyzed the bets made during a 24-month study period by the 4,595 most involved gamblers among a cohort of 48,114 people using an Internet service to gamble on sporting events. We applied two taxometric procedures (i.e., MAMBAC and MAXCOV) to three indicators of betting behavior: total money lost, total number of bets, and total money wagered. The results fail to provide support for the view that the most involved Internet sports gamblers include a distinct category of gamblers. More research is necessary to clarify the similar features of recreational and extreme gamblers and the dimensions that scientists can use to measure these behaviors. Finally, we discuss the implications of these findings for clinical, research, and public policy activities. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Confirming the latent structure and base rate of schizotypy: A taxometric analysis.

P. E. Meehl's (1962, 1990) model of schizotypy and the development of schizophrenia implies that the structure of liability for schizophrenia is dichotomous and that a "schizogene" determines membership in a latent class, or taxon (Meehl and R. R. Golden, 1982). The authors sought to determine the latent structure and base rate of schizotypy. They applied Meehl's (1973) MAXCOV-HITMAX taxometric analytic procedures to a subset of items from the Perceptual Aberration Scale (PAS; L. J. Chapman et al, 1978), a prominent psychometric index of schizotypy, derived from a randomly ascertained nonclinical sample (N?=?1,093). The results, in accordance with Meehl's conjectures, strongly suggest that schizotypy, as assessed by the PAS, is taxonic at the latent level with a general population taxon base rate of approximately .10. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Paranoid personality has a dimensional latent structure: Taxometric analyses of community and clinical samples.

Although paranoid personality is one of the most commonly diagnosed personality disorders and is associated with numerous negative life consequences, relatively little is known about the structural properties of this condition. This study examines whether paranoid personality traits represent a latent dimension or a discrete class (i.e., taxon). In Study 1, the authors conducted taxometric analyses of paranoid personality disorder criteria in a sample of 731 patients participating in the Collaborative Longitudinal Study of Personality Disorders project (Gunderson et al., 2000) who had been administered a semistructured diagnostic interview for personality disorders according to criteria of the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994). In Study 2, the authors conducted parallel analyses of the Paranoia scale of the Personality Assessment Inventory (PAI; L. C. Morey, 2007), using data from the PAI community and clinical normative databases. Analyses across both self-report and interview-based indicators offered compelling support for a dimensional structure. Additionally, analyses of external correlates in these data sets suggested that dimensional models demonstrated stronger validity coefficients with criterion measures than did dichotomous models. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chronic worry and the temporal dynamics of emotional processing.

Worriers avoid upsetting thoughts yet also demonstrate vigilance for aversive emotional information. Potentially, these processes coexist but are separated in time. Individuals scoring high on a measure of chronic uncontrollable worry were compared to low scorers during valence categorization of emotional stimuli with interleaved Stroop color word trials to monitor extended effects of emotional processing. High worriers were especially fast and accurate in judging the valence of emotional words compared to low worriers. Worriers also had smaller pupil diameters following personally relevant negative emotional stimuli compared to low worriers. Correlations with self-report scales indicated associations between the worrier pupil response profile and symptoms of chronic worry and depression. The combined behavioral and physiological data support theories of emotional vigilance followed by avoidance in worriers. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Resolving the latent structure of schizophrenia endophenotypes using expectation-maximization-based finite mixture modeling.

Prior research has focused on the latent structure of endophenotypic markers of schizophrenia liability, or schizotypy. The work supports the existence of 2 relatively distinct latent classes and derives largely from the taxometric analysis of psychometric values. The present study used finite mixture modeling as a technique for discerning latent structure and the laboratory-measured endophenotypes of sustained attention deficits and eye-tracking dysfunction as endophenotype indexes. In a large adult community sample (N=311), finite mixture analysis of the sustained attention index d′ and 2 eye-tracking indexes (gain and catch-up saccade rate) revealed evidence for 2 latent components. A putative schizotypy class accounted for 27% of the sample. A supplementary maximum covariance taxometric analysis yielded highly consistent results. Subjects in the schizotypy component displayed higher rates of schizotypal personality features and an increased rate of treated schizophrenia in their 1st-degree biological relatives compared with subjects in the other component. Implications of these results are examined in light of major theories of schizophrenia liability, and methodological advantages of finite mixture modeling for psychopathology research, with particular emphasis on genomic issues, are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluating the latent structure of the MMPI-2 F(p) scale in a forensic sample: A taxometric analysis.

P. A. Arbisi and Y. S. Ben-Porath (1995) originally proposed that the Infrequency Psychopathology scale, F(p), be used as the final step in an algorithm to determine the validity of a Minnesota Multiphasic Personality Inventory-2 (MMPI-2) protocol. The current study used taxometric procedures to determine the latent structure of F(p) among examinees with profiles that would necessitate the interpretation of F(p) when using Arbisi and Ben-Porath's proposed algorithm. Participants included a subsample of 289 consecutively referred pretrial forensic examinees adjudicated incompetent to stand trial with high Infrequency (F) scale scores, thereby providing a sample that would be expected to have a high base rate of persons with bona fide psychopathology and persons with incentive to overreport psychopathology. Using MAMBAC and MAXEIG, F(p) produced a taxonic latent structure within the subgroup of examinees who obtained raw scores on F of greater than 17. These results support Arbisi and Ben-Porath's original proposal to use F(p) to identify a distinct subgroup of overreported MMPI-2 protocols within forensic psychiatric examinees with high elevations on F. Implications and suggestions for future research are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of worry and evaluation stress on interhemispheric interaction.

Theories of cognitive functioning in anxiety propose decreased processing efficiency associated with worry but have paid scant attention to possible neural mechanisms. This study examined interhemispheric processing in individuals differing in self-reported worry under high- and low-evaluative conditions. Measures of interhemispheric processing were letter-matching tasks, with matches occurring either within or across hemispheres and requiring either a physical identity (A–A) or a name identity match (A–a). Results indicated that the across-hemisphere advantage (AHA) for the more difficult name identity task was exaggerated under high-evaluative conditions, indicating that interhemispheric processing was especially beneficial under the processing load of evaluation stress. Regardless of task condition, high worriers displayed a reduced AHA compared with low worriers, reflecting ineffective coordination of interhemispheric resources in worriers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Revisiting the latent structure of eating disorders: Taxometric analyses with nonbehavioral indicators.

Researchers have debated whether clinical eating disorders are best conceptualized as one extreme along a continuum of degree or as qualitatively different from less severe eating disturbances. Taxometric analysis, a set of procedures that assess the structure of a given disorder by detecting whether a latent taxon exists among its indicators, has just begun to be applied to eating disorder research. Its application to this domain may clarify whether eating disorders best conform to a dimensional (i.e.. continuum) or taxonic model. The latent structure of eating disorders was examined in a sample of 532 college women by using 2 popular taxometric procedures (i.e., maximum covariance analysis and latent mode analysis) with 5 nonbehavioral indicators of eating disorder symptomatology. Results across procedures suggest that the data are more indicative of a dimensional solution, as no latent taxon was uncovered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Restriction of working memory capacity during worry.

The authors report the first direct assessment of working memory capacity when people engage in worry. High and low worriers performed a random key-press task while thinking about a current worry or a positive personally relevant topic. High (but not low) worriers showed more evidence of restricted capacity during worry than when thinking about a positive topic. These findings suggest that high worriers have less residual working memory capacity when worrying than when thinking about other topics and, thus, have fewer attentional resources available to redirect their thoughts away from worry. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The structure of late-life depressive symptoms across a 20-year span: A taxometric investigation.

Past studies of the underlying structure of depressive symptoms have yielded mixed results, with some studies supporting a continuous conceptualization and others supporting a categorical one. However, no study has examined this research question with an exclusively older adult sample, despite the potential uniqueness of late-life depressive symptoms. In the present study, the underlying structure of late-life depressive symptoms was examined among a sample of 1,289 individuals across 3 waves of data collection spanning 20 years. The authors employed a taxometric methodology using indicators of depression derived from the Research Diagnostic Criteria (R. L. Spitzer, J. Endicott, & E. Robins, 1978). Maximum eigenvalue analyses and inchworm consistency tests generally supported a categorical conceptualization and identified a group that was primarily characterized by thoughts about death and suicide. However, compared to a categorical depression variable, depressive symptoms treated continuously were generally better predictors of relevant criterion variables. These findings suggest that thoughts of death and suicide may characterize a specific type of late-life depression, yet a continuous conceptualization still typically maximizes the predictive utility of late-life depressive symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The latent structure of childhood aggression: A taxometric analysis of self-reported and teacher-rated aggression in Israeli schoolchildren.

The purpose of this study was to determine whether the latent structure of childhood aggression, like the latent structure of adult antisocial behavior, is dimensional. One thousand and five Israeli schoolchildren completed a translation of the Buss-Perry Aggression Questionnaire (AQ; Buss & Perry, 1992) and were rated by their homeroom teachers on the Eyberg Child Behavior Inventory (ECBI; Robinson, Eyberg, & Ross, 1980). The AQ Physical Aggression and Verbal Aggression scales were combined to form the 1st indicator, the AQ Anger and Hostility scales were combined to form the 2nd indicator, the 10-item ECBI Oppositional Defiant Behavior Toward Adults scale composed the 3rd indicator, and the 8-item ECBI Conduct Problem Behavior scale composed the 4th indicator. Subjecting these indicators to taxometric analysis revealed consistent support for dimensional latent structure in the full sample as well as in 5 of the 6 subsamples. Childhood aggression, it would seem, differs quantitatively along a dimension (degree of aggression) rather than bifurcating into qualitatively distinct categories (aggressive vs. nonaggressive). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The latent structure of social anxiety disorder: Consequences of shifting to a dimensional diagnosis.

Despite longstanding debate over the nature of the boundary between social anxiety disorder (SAD) and less severe social anxiety, no study has tested directly whether the defining features of the disorder correspond to a latent category or dimension. The present study examined this question using data from the National Comorbidity Survey Replication (NCS-R), a nationally representative survey of the U.S. household population. Indicators representing the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM–IV; American Psychiatric Association, 1994) criteria for SAD were submitted to taxometric analyses in a subsample of adults (n = 2,166) who reported excessive social fear in their lifetime. Multiple taxometric procedures and consistency tests converged on a dimensional solution, suggesting that SAD is continuous with milder social anxiety. In follow-up analyses, a dimensional SAD diagnosis outperformed the DSM–IV diagnosis in predicting the subsequent onset of a range of clinically important outcomes. Large differences in associations with comorbid mood disorders, suicidality, and treatment seeking in particular favored the prognostic value of dimensional over categorical diagnosis. These findings support the validity and potential utility of a dimensional conceptualization of SAD that may inform efforts to revise the diagnosis for DSM–V. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The latent structure of attention-deficit/hyperactivity disorder in a clinic-referred sample.

The question of whether attention-deficit/hyperactivity disorder (ADHD) represents a continuum of attentional and executive dysfunction or a natural category has yet to be extensively investigated. Subjective report and neuropsychological data from 437 individuals referred for neuropsychological evaluation were analyzed using latent class and taxometric analyses (mean above minus below a cut [MAMBAC], maximum eigenvalue [MAXEIG], and latent mode [LMODE]). Results indicated no significant evidence for a taxonic representation of ADHD across multiple procedures and indicator sets. Similarly, there was no evidence that ADHD subtypes represent a qualitative distinction. These findings may suggest that current diagnostic conceptualizations are inadequate for accurately identifying and characterizing individuals with problems related to attention and executive dysfunction. Alternatively, the null findings may have resulted from inadequate indicator selection. A dimensional model may better facilitate accurate identification of individuals at risk for functional impairment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Continuity and discontinuity models of bulimia nervosa: A taxometric investigation.

Past research evaluating the continuity and discontinuity models of bulimia has produced inconclusive results. In the current study, we performed a taxometric analysis of bulimia nervosa using means above minus below a sliding cut and maximum covariance analysis with a sample of women diagnosed with bulimia nervosa (n?=?201) or women college students (n?=? 412). Indicators were derived from the Bulimia Test—Revised and the Eating Attitudes Test—26, and both a mixed sample and the nonclinical sample were analyzed. With both taxometric methods and both mixed and nonclinical samples, results were consistently suggestive of a latent taxon for bulimia. These results challenge a dimensional model of bulimia nervosa. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Looking on the bright side: Accessing benign meanings reduces worry.

This research investigated whether increasing access to benign outcomes of ambiguous events decreases excessive worry. Participants reporting high levels of worry were assigned either to practice in accessing benign meanings of threat-related homographs and emotionally ambiguous scenarios or to a control condition in which threatening or benign meanings were accessed with equal frequency. Results were assessed by use of a breathing focus task that involved categorizing the valence of thought intrusions before and after an instructed worry period and a test of working memory capacity available to participants while worrying. In comparison with the control group, the benign group reported fewer negative thought intrusions (as rated by both participants and an assessor) and less anxiety during the breathing focus task and showed greater residual working memory capacity while worrying. These findings suggest that enhancing access to benign outcomes is an effective method of reducing both the persistence of worry and its detrimental consequences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The latent structure of dietary restraint, body dissatisfaction, and drive for thinness: A series of taxometric analyses.

Although the latent structure of various eating disorders has been explored in previous studies, no published studies have examined the latent structure of theoretically relevant variables that have been shown to cut across eating disorder diagnoses. The current study examined 3 such variables (dietary restraint, body dissatisfaction, and drive for thinness) among undergraduate women using the taxometric method. The 5 items from the Eating Disorders Examination Questionnaire's Dietary Restraint subscale were used as dietary restraint indicators, whereas items from the Eating Disorders Inventory Body Dissatisfaction and Drive for Thinness subscales were used as indicators of body dissatisfaction and drive for thinness, respectively. As hypothesized, MAXCOV (maximum covariance) and MAMBAC (mean above minus below a cut) analyses suggested that all 3 variables are dimensional; therefore, individuals with high levels of reported dietary restraint, body dissatisfaction, and drive for thinness appear to differ in degree, but not in kind, from those with lower levels. Implications for prevention, assessment, classification, and treatment are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)