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.     

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.     

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.     

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

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 & Golden, 1982). The authors sought to determine the latent structure and base rate of schizotypy. They applied Meehl's (1973; Meehl & Golden, 1982) MAXCOV-HITMAX taxometric analytic procedures to a subset of items from the Perceptual Aberration Scale (PAS; Chapman, Chapman, & Raulin, 1978), a prominent psychometric index of schizotypy, derived from a randomly ascertained nonclinical university 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.     

The latent structure of psychopathy: a taxometric investigation of the Psychopathy Checklist Revised in a heterogeneous sample of male prison inmates

A taxometric analysis of the Psychopathy Checklist-Revised (PCL-R) is conducted on a group of 409 male maximum-, medium-, and minimum-security federal prison inmates using the four PCL-R facet scores (interpersonal, affective, impulsive lifestyle, and antisocial behavior) as indicators. Results obtained from three quasi-independent taxometric procedures-mean above minus below a cut, maximum eigenvalue, and latent mode factor analysis-reveal consistent support for a dimensional interpretation of the psychopathy concept in a moderately heterogeneous sample of participants. On the basis of these results, it is concluded that psychopathy falls along a continuum and that high and low scores on the PCL-R reflect quantitative differences in degree rather than qualitative differences in kind.     

Somatic symptom reporting has a dimensional latent structure: Results from taxometric analyses

Medically unexplained symptoms (MUS) are one of the key features of somatoform disorders. Although MUS are currently treated as both categorical (in terms of the diagnosis of somatoform disorders) and dimensional (in terms of quantitative measures of somatization/somatic symptom reporting), little is known about the empirical latent structure of MUS. Using taxometric analyses, the latent structure of somatic symptom reporting was analyzed with the Patient Health Questionnaire (PHQ)-15 in two student samples (N = 782 and N = 2,577) and a primary care sample (N = 519). We applied three popular taxometric methods: Maximum Eigenvalue (MAXEIG), Mean Above Minus Below a Cut (MAMBAC) and Latent-Mode (L-Mode). Simulation data were created to evaluate the appropriateness of the data for our analyses and to create the comparison curve fit index (CCFI) as an objective outcome measure. The results of all taxometric methods in any of the three data sets were in favor of a dimensional solution (CCFI < .50). Simulated taxonic and dimensional datasets differed substantially and the samples were appropriate for taxometric analysis. Accordingly, the latent structure of somatization/somatic symptom reporting as assessed by the PHQ-15 is dimensional in both primary care and student samples. Implications regarding the practical application as well as models of etiology and pathogenesis of somatic symptom reporting are discussed. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

The latent structure of social anxiety disorder and the performance only specifier: a taxometric analysis

Social anxiety disorder (SAD) is often treated as a discrete diagnostic entity that represents a naturally occurring class, though empirical evidence largely supports a dimensional conceptualization of social fears. Further, the inclusion of a “performance only” specifier in the DSM-5 implies that individuals who experience intense social anxiety exclusively in performance situations are distinct from those with broader social fears. The purpose of the present research was to examine the latent structure of SAD and the DSM-5 “performance only” specifier in a large nonclinical sample (n = 2019). Three taxometric procedures (MAXCOV, MAMBAC, and L-Mode) were applied to indicators derived from two commonly used measures of social anxiety. Results yielded convergent evidence indicating that social anxiety exhibits a dimensional latent structure. Further, social performance anxiety demonstrates continuous relationships with milder social fears, suggesting that the “performance only” specifier may not represent a discrete entity. The implications of these findings for the assessment, diagnosis, classification, and treatment of social anxiety are discussed.     

A taxometric investigation of unipolar depression in the national comorbidity survey

Ongoing debate has questioned whether unipolar depression is a dimensional or categorical phenomenon. Although past studies using taxometric methods have supported a dimensional interpretation, each has suffered from methodological limitations. The present study was designed to overcome these limitations through reanalysis of the National Comorbidity Survey. Two indicator sets were constructed from the depression-relevant questions of the Composite International Diagnostic Interview. Participants who endorsed the lifetime occurrence of significant depressed mood or anhedonia (n=4,577) were submitted to 2 nonredundant taxometric procedures (maximum eigenvalue and means above minus below a cut), additional consistency tests, and recently developed simulation techniques. All results converged on a dimensional solution. The implications of these findings on assessment, treatment, and research design are discussed.     

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.     

Latent structure of anxiety: taxometric exploration

Taxometrics is a statistical tool that can be used to discern categories from continua. Taxometric analyses (MAXCOV and MAXEIG) were conducted in a large nonclinical sample (N=1,215) to determine whether extreme anxiety forms a distinct psychopathological category, an anxiety taxon. Anxiety was operationalized with self-report measures of subjective anxiety, anxious cognitive style, physiological arousal, and anxiety-related impairment. Procedures consistently identified a taxon with a prevalence of approximately 11%. Examination of the taxon's convergent and discriminant validity revealed that it reflects general distress rather than physiological arousal. Taxon membership showed some evidence of incremental validity.     

A latent structure for the simplex

A perfect Guttman scale generates a perfect Guttman simplex. This is capitalized on to get a transformation useful in a kind of non-linear factor analysis applicable to empirical correlations resembling but not necessarily conforming to a perfect simplex.A Gramian factorization—square, symmetric, possibly of low rank but with no negative characteristic roots—of empirical correlations is transformed into latent information about nonlinear regressions of tests on a single underlying dimension. Class intervals on that continuum are defined in terms of their standard score profiles on the tests. Each class interval exhibits local independence, so that individual members may vary but may not covary in their profiles.The method is flexible as to choice of diagonals, fitted rank, and exact shape of resulting non-linear regressions, so long as those regressions are essentially monotonic and have a proper progression of curvatures. Construction of the needed transformation for data of any size is outlined, and the problem of metric for the latent continuum is given several solutions.An empirical example is provided with full and low rank solutions involving different diagonal choices.This research was conducted under Grant Nonr(G)-00033-63 of the Office of Naval Research. Reproduction of this paper, in whole or in part, is permitted for any purpose of the United States government.     

A taxometric study of the Adult Attachment Interview

This study is the first to examine the latent structure of individual differences reflected in the Adult Attachment Interview (AAI; C. George, N. Kaplan, & M. Main, 1985), a commonly used and well-validated measure designed to assess an adult's current state of mind regarding childhood experiences with caregivers. P. E. Meehl's (1995) taxometric methods (i.e., MAXCOV-HITMAX) were applied to data from 504 AAIs. Analyses revealed that the variation underlying secure versus dismissing states of mind was more consistent with a dimensional than a taxonic model. (Taxometric analyses of preoccupation were indeterminate.) In addition, variation in secure adults' (n=278) reports about their early experiences revealed little evidence for qualitative groups of earned- and continuous-secures. Rather, the inferred life experiences of secure adults appeared to be distributed continuously. Findings are discussed in terms of their theoretical implications regarding the phenomenon of earned-security specifically and variation underlying secure and insecure states of mind more generally. The consequences of these analyses for AAI reliability training and coding are also explored.     

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.     

An investigation of worry and sense of humor

To investigate the relationship between worry and sense of humor, the author administered the Worry Domains Questionnaire (WDQ; F. Tallis, M. Eysenck, & A. Matthews, 1992) and the Multidimensional Sense of Humor Scale (MSHS; J. A. Thorson & F. C. Powell, 1993) to 140 undergraduates. Worry was negatively related to sense of humor. Results of a stepwise regression, using the WDQ as the criterion and the MSHS factors as predictors, showed that the humor production factor of the MSHS loaded negatively on Step 1 and the coping with humor factor loaded positively on Step 2. The results are discussed in relation to W. E. Kelly and M. J. Miller's (1999) cognitive model of worry and worry as a coping strategy.     

A taxometric analysis of psychopathic personality

Although a common assumption throughout much of the professional and popular literature is that psychopaths are qualitatively different from others, very few studies have examined the latent structure of psychopathy. Whether psychopathy is a discrete category or a continuous dimension may have implications for research on the assessment, etiology, and treatment of this disorder. This study examined the latent structure of psychopathy in a sample of 309 jail and prison inmates. Three taxometric procedures were used to analyze indicators drawn from the Psychopathic Personality Inventory (S. O. Lilienfeld & B. P. Andrews, 1996), a self-report instrument. Consistent with prior studies that used other measures of psychopathy, none of the analyses was consistent with a taxonic solution, suggesting that psychopathic personality may be best understood as existing on a continuum.     

A taxometric study of hypochondriasis symptoms

Hypochondriasis has been conceptualized as both a distinct category that is characterized by a disabling illness preoccupation and as a continuum of health concerns. Empirical support for one of these theoretical models will clarify inconsistent assessment approaches and study designs that have impeded theory and research. To facilitate progress, taxometric analyses were conducted to determine whether hypochondriasis is best understood as a discrete category, consistent with the DSM, or as a dimensional entity, consistent with prevailing opinion and most self-report measures. Data from a large undergraduate sample that completed 3 hypochondriasis symptom measures were factor analyzed. The 4 factor analytically derived symptom indicators were then used in these taxometric analyses. Consistent with our hypotheses and existing theory, results supported a dimensional structure for hypochondriasis. Implications for the conceptualization of hypochondriasis and directions for future study are discussed.     

Using taxometric analysis to distinguish a small latent taxon from a latent dimension with positively skewed indicators: the case of involuntary defeat syndrome

Joining the debate on the structure of depression, S. R. H. Bearh and N. Amir (2003) analyzed college students' responses to 6 Beck Depression Inventory (BDI) items with predominantly somatic content and concluded that they identified a small latent taxon corresponding to involuntary defeat syndrome. An exact replication of these analyses yielded virtually identical taxometric results, but parallel analyses of simulated taxonic and dimensional comparison data matching the intercorrelations and skewed distributions of the BDI items showed the results to be more consistent with dimensional than with taxonic latent structure. Analyses in a clinical sample with nonskewed indicators further supported a dimensional interpretation. The authors discuss methodological strategies for conducting and interpreting taxometric analyses under the adverse conditions commonly encountered in psychopathology research, including skewed indicators and small putative taxa.     

Detecting latent taxa: Monte Carlo comparison of taxometric, mixture model, and clustering procedures

A Monte Carlo evaluation of four procedures for detecting taxonicity was conducted using artificial data sets that were either taxonic or nontaxonic. The data sets were analyzed using two of Meehl's taxometric procedures, MAXCOV and MAMBAC, Ward's method for cluster analysis in concert with the cubic clustering criterion and a latent variable mixture modeling technique. Performance of the taxometric procedures and latent variable mixture modeling were clearly superior to that of cluster analysis in detecting taxonicity. Applied researchers are urged to select from the better procedures and to perform consistency tests.