Interpretation of bodily symptoms in hypochondriasis.

Although it has been suggested that hypochondriasis is caused by the misinterpretation of innocuous bodily sensations, support for this hypothesis rests largely upon uncontrolled self-report. We investigated the interpretation of ambiguous bodily sensations in three experiments using separate samples of non-clinical subjects differing in level of hypochondriacal concern. Results confirmed that subjects with high hypochondriacal concern endorse more thoughts about illness interpretations of bodily sensations, but reported thought content resembled 'catastrophic' rather than the 'non-emergency' thoughts suggested by Warwick and Salkovskis (Hypochondriasis. Behavior Research and Therapy, 28, 105-117, 1990). Presence of an interpretive bias was further supported in a study of recognition bias for disambiguated versions of ambiguously threatening sentences, although this applied as much to social as to illness threats. A final experiment failed to support the hypothesis of an automatic inference bias, but did show that subjects with high hypochondriacal concern were quicker to correctly identify previously exposed illness words. Thus, reported thoughts are consistent with catastrophic interpretations of common bodily sensations, but interpretive bias may not be limited to illness threat. However, high hypochondriacal subjects do show a more specific enhanced perceptual sensitivity to illness cues, which may play a role in maintaining their concern with bodily symptoms.     

A taxometric study of borderline personality disorder

Taxometric methodology was used to determine whether borderline personality disorder (BPD) represents a taxon that is categorically distinct from normal personality or whether it falls on a dimensional continuum with normality. Two taxometric procedures were used with a sample of 1,389 outpatients assessed for BPD symptoms by semistructured interview. The procedures indicated that BPD does not represent a latent category. Implications are drawn for the conceptualization and etiology of BPD, and for the categorical versus dimensional status of personality disorders in general.     

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.     

A taxometric study of the Center for Epidemiological Studies Depression Scale

The authors assessed the latent structure of depressive symptoms as measured by the Center for Epidemiological Studies Depression Scale (CES-D; L. S. Radloff, 1977). By using taxometric procedures, the authors conducted analyses of CES-D data obtained from a large college student population. These procedures incorporated strategies for interpreting analyses of skewed indicators and small putative taxa. The authors hypothesized that CES-D total scores would be represented as a dimension, with a taxonic distribution of a factor incorporating somatic symptoms. Results indicated that all CES-D factors, including the factor composed of somatic complaints, were dimensional. Administration of the Diagnostic Interview Schedule-IV (L. N. Robins, L. Marcus, & W. Reich, 1996) to one quarter of the participants indicated that the CES-D was effective in identifying cases of current or recent clinical depression. Evidence of the dimensionality of CES-D indicators in a student population is consistent with a continuity view of depressive symptoms.     

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.     

Subtyping obsessive-compulsive disorder: A taxometric analysis

Obsessive-compulsive disorder (OCD) is a heterogeneous condition comprising multiple symptoms. Researchers have identified OCD subtypes using a range of symptom-based research methods, including factor and cluster analyses and examination of differential treatment response. These methods can be challenged on the grounds that they fail to demonstrate the existence of discrete taxonomic entities. Furthermore, no study has examined subtyping on the basis of cognitive characteristics. In the present study, the categorical vs. dimensional status of 6 possible subtypes of OCD was examined using taxometric methods. Three potential cognitive subtypes (based on high levels of responsibility/threat estimation, perfectionism/certainty, and importance/control of thoughts) and 3 potential symptomatic subtypes (based on elevated levels of contamination obsessions and cleaning compulsions, checking, and obsessionality) were examined using the MAXEIG and MAMBAC procedures in a sample of 404 diagnosed cases of OCD. Findings favored dimensional models of the potential responsibility, perfectionism, checking, and contamination subtypes, but offered qualified support for taxonic models of the importance/control of thoughts and obsessional subtypes. Implications for the subclassification of OCD are discussed.     

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.     

A taxometric investigation of the latent structure of worry

Researchers have described 2 types of worriers, normal and pathological, who differ in the frequency, intensity, and controllability of their worry experiences. Although normal and pathological worry are generally treated as separate though related phenomena, no study has tested for separateness against the alternative hypothesis that all worry exists along a single dimension. In the present study, worry ratings of 1,588 college students were submitted to taxometric procedures designed to evaluate latent structure. Results provided evidence for the dimensionality of worry. These findings suggest that generalized anxiety disorder (GAD), whose central feature is worry, may also be quantitatively rather than qualitatively different from normal functioning. The authors argue that a focus on normal and pathological extremes has constrained the study of worry phenomena and that dimensional conceptualization of worry may significantly enhance understanding of both worry and GAD.     

Optimists or optimistic: Replication of a taxometric study on optimism

Hope and optimism are variants of individual differences regarding positive expectancies for the future. Previous literature describes the relationship of hope and optimism to various outcomes such as psychological adjustment, achievement, problem solving, and health-related concerns; however, few studies investigate its latent structure. Eichner, Kwon, and Marcus (2014) explore optimism’s latent structure through taxometric procedures and provide support for a dimensional construct. In light of recent debate over the replicability of scientific findings, the present study aimed to replicate these findings in an independent sample. Taxometric analyses are consistent with the original study, providing further support for the dimensional latent structure of optimism.     

A taxometric analysis of the MMPI-2 Depression scales

The MMPI (Hathaway & McKinley, 1943) and MMPI-2 (Butcher et al., 2001) have long been used as measures of psychopathology. Both clinicians and researchers have noted the widespread existence of negative affectivity on the MMPI and MMPI-2 that may elevate scale scores and eclipse the tests' ability to differentiate depression from other clinical disorders. Using taxometric analyses, in this study we sought to test directly whether the MMPI-2 depression scales could differentiate patients with depressive symptoms from patients with other disorders. A large psychiatric sample (N = 2,000) was utilized and analyses were run separately for men and women. Taxometric analyses did not find a MMPI-2 Depression scale cut point that categorizes patients with depressive symptoms from other patients. Rather, these findings support previous studies finding an underlying dimensionality of depression. We discuss implications for MMPI-2 scale use and depression nosology in light of these findings.     

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.     

Clarifications about taxometric method

Taxometrics is a statistical procedure for determining whether relationships among observables reflect the existence of a latent taxon (type, species, category, disease entity). A formal-numerical definition is needed because intuitive, commonsense notions of “carving nature at its joints” or “identifying natural kinds” cannot resolve disagreements as to taxonic reality for hard cases. Specific etiology (e.g., major gene, germ, traumatic event) is often unknown and is not appropriate in nonmedical domains. Lacking an infallible criterion, the taxonic inference relies on the internal configural relations among the conjectural fallible indicators. An essential feature is multiple consistency tests that will not be satisfied if the latent structure is not taxonic or the parameters are badly estimated. Common misconceptions are that the taxon must be “sharply” distinguished, quantitative indicators must be bimodal, the causal origin must be biological, emergence of a large dimensional factor refutes taxonicity, and adopting a taxon is a mere matter of convention or preference.     

Anxiety as a context for understanding associations between hypochondriasis, obsessive-compulsive, and panic attack symptoms

In the context of the integrative model of anxiety and depression, we examined whether the essential problem of hypochondriasis is one of anxiety. When analyzed, data from a large nonclinical sample corresponded to the integrative model's characterization of anxiety as composed of both broad, shared and specific, unique symptom factors. The unique hypochondriasis, obsessive-compulsive, and panic attack symptom factors all had correlational patterns expected of anxiety with the shared, broad factors of negative emotionality and positive emotionality. A confirmatory factor analysis showed a higher-order, bifactor model was the best fit to our data; the shared and the unique hypochondriasis and anxiety symptom factors both contributed substantial variance. This study provides refinements to an empirically based taxonomy and clarifies what hypochondriasis is and, importantly, what it is not.     

An experimental analysis of hypochondriasis

Hypochondriasis (HC) involves preoccupation with fears of having a serious medical illness based on the misinterpretation of benign bodily perturbations. Individuals with HC also perform behaviors such as checking and reassurance-seeking presumably to reduce health-related fears. Experimental behavioral analyses of HC symptoms, however, are lacking. In the present study, 27 patients with HC were exposed to personally relevant health-related stimuli under one of two conditions: (a) subsequently performing safety-seeking behaviors (e.g., checking) (n=14) or (b) subsequently being instructed not to perform such behaviors (n=13). In both groups, subjective anxiety and urges to perform safety behaviors were monitored for 1h. Results indicated that exposure to the personally relevant health trigger provoked anxiety and urges to perform safety behaviors. For patients who performed such behaviors, these feelings were reduced. For patients who did not, a more gradual reduction of anxiety and urges was observed. Findings are discussed in terms of the conceptualization and treatment of HC behavior, and are relevant to HC's possible relationship to panic and obsessive-compulsive disorder.     

Envy and jealousy as discrete emotions: A taxometric analysis

Envy and jealousy may differ in kind or only by degree. In a study of emotion episodes recalled by 291 subjects, two forms of taxometric analysis were used to test between categorical and dimensional models of the two emotions. The two emotions yielded strong convergent evidence of discreteness, and commonly cooccurred. However, although subjects rated their episode to contain similar levels of envy and jealousy, both terms were equally correlated with the presence of envy features and neither term was correlated substantially with the presence of jealousy features. Implications ar drawn for the study of categorical distinctions between emotions, and for the relation between emotions and emotion terms.The authors would like to thank Tammy Carter for assistance with data collection.     

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.     

The distribution of hand preference is discrete: A taxometric examination

The dominant genetic models of human handedness ( Annett, 1985 ; McManus, 1985a ) have contrasting views on its nature. Whereas Annett's model proposes that handedness is distributed continuously (following the distribution of performance asymmetries of the hands), McManus's model proposes that handedness is distributed dichotomously. The aim of this study was to investigate the nature of the underlying distribution. The taxonomy of hand preference was analysed by two independent taxometric procedures, ‘mean‐above–mean‐below‐a‐cut’ and ‘maximum‐eigenvalue’, separately in two geographically, demographically, and culturally distinct samples; one of Australian adults (N=787), and the other of Serbian high school students (N=1,224). The analyses revealed a latent categorical structure in both samples, with estimated mean base‐rates of a right‐handed taxon of 0.80 and 0.94 from the two analyses of the adult sample and of 0.79 and 0.93 from the two analyses of the high school sample. Subsequent analyses showed that the initial right‐handed class could be subdivided into consistent and inconsistent right‐handed subclasses in both samples. A supplementary analysis, including a measure of hand proficiency in a subset of the sample of Australian adults (N=596), also revealed a latent categorical structure, showing evidence for a categorical latent structure from a continuous measure of hand performance. We conclude that the distribution of hand preferences in humans is discrete and not continuous.