Dimensional models of psychopathology: research agenda and clinical utility

This commentary emphasizes the implications for a mental health research agenda that stem from the papers in this special section on dimensional models of psychopathology. These include the need to extend dimensional models to a wider range of psychopathology; the relationship of the dimensions described in these papers, largely based on symptom and self-report measures, to findings from current research in genetics, neuroimaging, and other domains of neuroscience; the need for new scales that can assess the entire range of relevant dimensions with modern psychometric techniques; and ways to employ these dimensions in applied clinical situations. It is concluded that hierarchical dimensional models offer powerful ways of organizing our thinking about psychopathology and will serve to guide many promising avenues of future research.     

Random utility models with equality: An apparent,but not actual,generalization of random utility models

A probabilistic model for choice, and preference, is introduced that includes (Tversky's) elimination by aspects model, and the random utility model, as special cases. The model is based on a covert sequential elimination process, the element that is finally chosen in a simple choice experiment being the eventual lone survivor of the elimination process. The model leads us to question the usual form of simple choice experiments, in which a subject must (eventually) choose one of the currently available alternatives, and to suggest that a much more realistic experimental design would allow the subject the no-choice option, i.e., he may refuse to accept any of the currently available alternatives.     

Synchronizing programs using Macromedia Director plug-ins: An example from the field of developmental psychopathology

Synchronizing the display of a stimulus with physiological recording or subjects’ behavioral responses is crucial for acquiring valid measures of performance. This article describes a technique for integrating the presentation of stimuli, behavior reports, and physiological data employing Macromedia Director and a standard biometric program using an example from the field of developmental psychopathology. Our experience has been that the use of this technique is effective in creating complex protocols for research. Although the temporal accuracy available from this particular method is adequate for some experiments, it is not suited for investigations requiring single millisecond accuracy. Considerations and suggestions for utilizing this and similar techniques for integrating data collection and stimuli presentation are discussed.     

Diathesis-stress models of psychopathology: A quantitative genetic perspective

When genetics is considered in diathesis-stress models of psychopathology, it is often assumed that heredity provides the diathesis and environmental factors are responsible for the stressor. We discuss two quantitative genetic models relevant to the diathesis-stress construct. One model focuses on genotype-environment interaction, which is the usual way in which genetic influence is represented in diathesis-stress models. A second model—genotype-environment correlation—provides an alternative that represents both genetic and environmental influences relevant to the development of psychopathology. Implications of these models for clinical research are discussed.     

Artists' vulnerability to psychopathology: Towards an integrative cognitive perspective

A relationship is commonly reported between high levels of artistic creativity and mental health problems (e.g., depression or psychosis), and it is now becoming clearer that the divergent cognitive style associated with creativity has commonalities with some of the processes involved in the development and maintenance of some psychological difficulties. Our aim was to investigate the nature of this cognitive style. More specifically, we considered the profile of probabilistic reasoning and associated problem solving abilities, as both of these mechanisms have been found to be integral to major forms of clinical dysfunction. We assessed levels of creative potential, mood, probabilistic reasoning, and problem solving abilities in 66 arts and 85 science undergraduate volunteers. As predicted, art students showed higher levels of creative potential and experienced lower levels of mood than their science peers. Differences in probabilistic reasoning were observed which are in keeping with the pattern reported to be present in those suffering with psychosis in that they tended to ‘jump to conclusions’. Art students also displayed both poorer problem solving abilities and self‐appraisal of their problem solving skills. Our results extend previous findings associated with the mediating role of cognitive processes in the relationship between creativity and some forms of psychopathology. Implications for the prevention and treatment of psychological difficulties in the creative are highlighted.     

Clinical utility of dimensional models for personality pathology

Clinical utility is defined as the extent to which the DSM assists clinical decision makers in fulfilling the various clinical functions of a psychiatric classification system. Distinction is made between elements of diagnostic validity that are more or less conditional to utility (i.e., coverage, and consistency with etiology and prognosis) and components of clinical utility in the narrow sense of the term (i.e., user acceptability and accuracy, communication, reliability, subtlety, and clinical decision making). Clinical utility is often considered the driving force behind the respective revisions of the DSM system, yet it has been difficult if not impossible to obtain reasonable levels of clinical utility within categorical classifications of personality disorders. This paper presents evidence that a dimensional diagnostic system will substantially improve clinical utility, especially with respect to coverage, reliability, subtlety, and clinical decision making. In addition, some evidence suggests that the purely dimensional models outperform the so-called hybrid models (i.e., dimensional profiling of categories) with respect to coverage, consistency with etiology, subtlety, and clinical decision making. Several research options that might inform future revisions, including the choice or development of a dimensional classification, are suggested.     

An integrative framework for psychopathology and psychotherapy

This article presents an integrative framework for psychopathology and psychotherapy. The framework differs in kind from previous ones in that it is entirely pre-empirical (specifically, conceptual and logical) in character and does not represent an attempt to create a new empirical theory (cf. Newton's pre-empirical creation of a new conceptual system, which creation proved a necessary precondition for his subsequent empirical contentions). The present integration is accomplished in three parts. In the first of these, a definition of pathology as behavioral disability or functional impairment is presented and defended. In the second, this definition is used as a centerpiece to achieve a logical unification of many prominent explanations of psychopathology that are at present widely considered to be theoretically divergent and incompatible. In part three, established forms of intervention from our most influential schools of psychotherapy are shown to be both conceptually coherent and compatible in practice within the present overarching framework.     

Determining informative priors for cognitive models

The development of cognitive models involves the creative scientific formalization of assumptions, based on theory, observation, and other relevant information. In the Bayesian approach to implementing, testing, and using cognitive models, assumptions can influence both the likelihood function of the model, usually corresponding to assumptions about psychological processes, and the prior distribution over model parameters, usually corresponding to assumptions about the psychological variables that influence those processes. The specification of the prior is unique to the Bayesian context, but often raises concerns that lead to the use of vague or non-informative priors in cognitive modeling. Sometimes the concerns stem from philosophical objections, but more often practical difficulties with how priors should be determined are the stumbling block. We survey several sources of information that can help to specify priors for cognitive models, discuss some of the methods by which this information can be formalized in a prior distribution, and identify a number of benefits of including informative priors in cognitive modeling. Our discussion is based on three illustrative cognitive models, involving memory retention, categorization, and decision making.     

Real-time generation of representations for cognitive models

Computerized models of human cognition and behavior have been used to help researchers refine their theories of cognitive processes. Two difficulties inherent in using these cognitive models are that building representations of to-be-modeled groups or individuals is (1) time-consuming and (2) prone to error when performed manually. The use of computerized tools to build representations for cognitive models could alleviate these problems. Such a set of tools has been developed and applied to the task of modeling individual aviation pilots performing flight maneuvers in real time. A study conducted with 27 pilots confirms the accuracy of the computer-generated representations.     

Pediatric trichotillomania: descriptive psychopathology and an open trial of cognitive behavioral therapy

In study 1, 46 children and adolescents with trichotillomania who sought treatment at 2 specialty outpatient clinics were assessed. Most children reported pulling hair from multiple sites on the body, presented with readily visible alopecia, reported spending 30-60 minutes per day pulling or thinking about pulling, and reported experiencing significant distress about their symptoms. Most were described by their parents as having significant problems in school functioning. Few children met criteria for obsessive-compulsive disorder or tic disorder. Child and family rates of other forms of psychopathology were high. In study 2, 22 of these children were enrolled in an open trial of individual cognitive behavioral therapy with particular attention to relapse prevention. Trichotillomania severity decreased significantly and 77% of children were classified as treatment responders at post-treatment and 64% at 6-month follow-up.     

Nightmare frequency versus nightmare distress: relations to psychopathology and cognitive style.

The hypotheses that psychopathology is related to nightmare distress but not nightmare frequency and that cognitive style is related to nightmare frequency were examined. The sample consisted of 85 subjects (58 women and 27 men) who completed several measures: a sleep and dream inventory, Symptom Check List-90-R, Fear Survey Schedule-II, Beck Depression Inventory, an abbreviated version of the Harvard Group Scale of Hypnotic Susceptibility, Vividness of Visual Imagery, an absorption scale, a social desirability scale, and the Boundaries Questionnaire. The results strongly support the first hypothesis but only slightly the second. Such findings underscore the need to differentiate nightmare frequency from suffering (waking distress associated with nightmares) and suggest that although frequency may be related to an intensification of dreaming process, suffering is related to waking emotional adjustment.     

Higher-order latent trait models for cognitive diagnosis

Higher-order latent traits are proposed for specifying the joint distribution of binary attributes in models for cognitive diagnosis. This approach results in a parsimonious model for the joint distribution of a high-dimensional attribute vector that is natural in many situations when specific cognitive information is sought but a less informative item response model would be a reasonable alternative. This approach stems from viewing the attributes as the specific knowledge required for examination performance, and modeling these attributes as arising from a broadly-defined latent trait resembling theϑ of item response models. In this way a relatively simple model for the joint distribution of the attributes results, which is based on a plausible model for the relationship between general aptitude and specific knowledge. Markov chain Monte Carlo algorithms for parameter estimation are given for selected response distributions, and simulation results are presented to examine the performance of the algorithm as well as the sensitivity of classification to model misspecification. An analysis of fraction subtraction data is provided as an example. This research was funded by National Institute of Health grant R01 CA81068. We would like to thank William Stout and Sarah Hartz for many useful discussions, three anonymous reviewers for helpful comments and suggestions, and Kikumi Tatsuoka and Curtis Tatsuoka for generously sharing data.     

Frontal tests and models for cognitive ageing

Results of investigations of how specific behavioural changes in old age may be related to local changes in the brain have been discrepant because of neglect of methodological issues. Among these are neglect of the reliability and validity of frontal and executive tests; the operational definition and construct validity of hypothetical functional processes such as “inhibition”; the nature and origins of mutual relationships between tests; the relationships of test performance to higher order constructs of general mental ability such as “gf” and, most importantly, problems of cohort selection arising from imprecise definitions of the models of the ageing process. These problems are illustrated by a discussion of the results of several experiments in which younger and older groups of people are compared on frontal and executive tests.     

The use of latent trajectory models in psychopathology research

Despite the recent surge in the development of powerful modeling strategies to test questions about individual differences in stability and change over time, these methods are not currently widely used in psychopathology research. In an attempt to further the dissemination of these new methods, the authors present a pedagogical introduction to the structural equation modeling based latent trajectory model, or LTM. They review several different types of LTMs, discuss matching an optimal LTM to a given question of interest, and highlight several issues that might be particularly salient for research in psychopathology. The authors augment each section with a review of published applications of these methods in psychopathology-related research to demonstrate the implementation and interpretation of LTMs in practice.     

To thy own self be true: finding the utility of cognitive information feedback

This study utilized Extended MSE Analysis to investigate the effects of two types of cognitive feedback on judgmental accuracy. Participants judged the income levels of respondents to the General Social Survey in both dilution and non‐dilution scenarios, received feedback, and then repeated those judgments. Task information feedback produced improvements in judgmental accuracy, and this improvement occurred primarily from a reduction in the standard deviation of participants' judgments and an increase in the consistency with which they applied their judgment policies. Cognitive information feedback produced little effect when presented alone, but produced accuracy gains superior to all other conditions when combined with task information. We conclude by discussing the specific conditions whereby each form of feedback is likely to be effective. Copyright © 2005 John Wiley & Sons, Ltd.