Megan J. Hobbs

The structure of psychopathology: Toward an expanded quantitative empirical model

There has been substantial recent interest in the development of a quantitative, empirically based model of psychopathology. However, the majority of pertinent research has focused on analyses of diagnoses, as described in current official nosologies. This is a significant limitation because existing diagnostic categories are often heterogeneous. In the current research, we aimed to redress this limitation of the existing literature, and to directly compare the fit of categorical, continuous, and hybrid (i.e., combined categorical and continuous) models of syndromes derived from indicators more fine-grained than diagnoses. We analyzed data from a large representative epidemiologic sample (the 2007 Australian National Survey of Mental Health and Wellbeing; N = 8,841). Continuous models provided the best fit for each syndrome we observed (distress, obsessive compulsivity, fear, alcohol problems, drug problems, and psychotic experiences). In addition, the best fitting higher-order model of these syndromes grouped them into three broad spectra: Internalizing, Externalizing, and Psychotic Experiences. We discuss these results in terms of future efforts to refine emerging empirically based, dimensional-spectrum model of psychopathology, and to use the model to frame psychopathology research more broadly.

Emotional disorders: Cluster 4 of the proposed meta-structure for DSM-V and ICD-11

BACKGROUND The extant major psychiatric classifications DSM-IV, and ICD-10, are atheoretical and largely descriptive. Although this achieves good reliability, the validity of a medical diagnosis would be greatly enhanced by an understanding of risk factors and clinical manifestations. In an effort to group mental disorders on the basis of aetiology, five clusters have been proposed. This paper considers the validity of the fourth cluster, emotional disorders, within that proposal. METHOD We reviewed the literature in relation to 11 validating criteria proposed by a Study Group of the DSM-V Task Force, as applied to the cluster of emotional disorders. RESULTS An emotional cluster of disorders identified using the 11 validators is feasible. Negative affectivity is the defining feature of the emotional cluster. Although there are differences between disorders in the remaining validating criteria, there are similarities that support the feasibility of an emotional cluster. Strong intra-cluster co-morbidity may reflect the action of common risk factors and also shared higher-order symptom dimensions in these emotional disorders. CONCLUSION Emotional disorders meet many of the salient criteria proposed by the Study Group of the DSM-V Task Force to suggest a classification cluster.

Psychotic-like experiences in a community sample of 8000 children aged 9 to 11 years: an item response theory analysis

BACKGROUND Psychotic-like experiences (PLEs) in the general population are common, particularly in childhood, and may constitute part of a spectrum of normative development. Nevertheless, these experiences confer increased risk for later psychotic disorder, and are associated with poorer health and quality of life. METHOD This study used factor analytic methods to determine the latent structure underlying PLEs, problem behaviours and personal competencies in the general child population, and used item response theory (IRT) to assess the psychometric properties of nine PLE items to determine which items best represented a latent psychotic-like construct (PSY). A total of 7966 children aged 9-11 years, constituting 95% of eligible children, completed self-report questionnaires. RESULTS Almost two-thirds of the children endorsed at least one PLE item. Structural analyses identified a unidimensional construct representing psychotic-like severity in the population, the full range of which was well sampled by the nine items. This construct was discriminable from (though correlated with) latent dimensions representing internalizing and externalizing problems. Items assessing visual and auditory hallucination-like experiences provided the most information about PSY; delusion-like experiences identified children at more severe levels of the construct. CONCLUSIONS Assessing PLEs during middle childhood is feasible and supplements information concerning internalizing and externalizing problems presented by children. The hallucination-like experiences constitute appropriate items to screen the population to identify children who may require further clinical assessment or monitoring. Longitudinal follow-up of the children is required to determine sensitivity and specificity of the PLE items for later psychotic illness.

EEG abnormalities in adolescent males with AD/HD.

OBJECTIVE This study investigated EEG abnormalities in adolescents with attention-deficit/hyperactivity disorder (AD/HD). METHODS Fifteen AD/HD subjects and 15 control subjects participated in this study. All subjects were between 14 and 17 years of age. The EEG was recorded from 19 electrode sites and was analysed to provide estimates of both absolute and relative power in the delta, theta, alpha and beta bands. Theta/alpha and theta/beta ratio coefficients were also calculated. RESULTS Across the scalp, AD/HD subjects were characterised by greater absolute delta and theta activity, and an increased theta/beta ratio compared to controls. No group differences were found for either absolute or relative alpha, or absolute beta. However, AD/HD subjects demonstrated a reduction in relative beta activity in the posterior regions. CONCLUSIONS The AD/HD group showed significant deviations from normal CNS development, in particular in posterior regions. This supports previous suggestions that individuals with an EEG profile that is not indicative of a maturational lag are more likely to have AD/HD during adolescence. SIGNIFICANCE This is the first study to investigate EEG abnormalities in adolescents with AD/HD during an eyes-closed resting condition.

DSM-IV post-traumatic stress disorder among World Trade Center responders 11–13 years after the disaster of 11 September 2001 (9/11)

Background Post-traumatic symptomatology is one of the signature effects of the pernicious exposures endured by responders to the World Trade Center (WTC) disaster of 11 September 2001 (9/11), but the long-term extent of diagnosed Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) post-traumatic stress disorder (PTSD) and its impact on quality of life are unknown. This study examines the extent of DSM-IV PTSD 11–13 years after the disaster in WTC responders, its symptom profiles and trajectories, and associations of active, remitted and partial PTSD with exposures, physical health and psychosocial well-being. Method Masters-level psychologists administered sections of the Structured Clinical Interview for DSM-IV and the Range of Impaired Functioning Tool to 3231 responders monitored at the Stony Brook University World Trade Center Health Program. The PTSD Checklist (PCL) and current medical symptoms were obtained at each visit. Results In all, 9.7% had current, 7.9% remitted, and 5.9% partial WTC-PTSD. Among those with active PTSD, avoidance and hyperarousal symptoms were most commonly, and flashbacks least commonly, reported. Trajectories of symptom severity across monitoring visits showed a modestly increasing slope for active and decelerating slope for remitted PTSD. WTC exposures, especially death and human remains, were strongly associated with PTSD. After adjusting for exposure and critical risk factors, including hazardous drinking and co-morbid depression, PTSD was strongly associated with health and well-being, especially dissatisfaction with life. Conclusions This is the first study to demonstrate the extent and correlates of long-term DSM-IV PTSD among responders. Although most proved resilient, there remains a sizable subgroup in need of continued treatment in the second decade after 9/11.

Frequency and quality of mental health treatment for affective and anxiety disorders among Australian adults.

Objectives: To describe the frequency, type and quality of mental health treatment among Australian adults with past‐year affective and/or anxiety disorders.

The Effect of the Draft DSM-5 Criteria for GAD on Prevalence and Severity

Objective: Options for revising the DSM-IV Generalized Anxiety Disorder (GAD) diagnostic criteria have been made by the DSM-5 Anxiety, Obsessive-Compulsive, Post-traumatic and Dissociative Disorders Work Group. It has been proposed that renaming the disorder Generalized Worry Disorder, clarifying criterion A to emphasize the primacy of worry, reducing the duration required, altering the list of associated symptoms to reflect the concomitants of worry that are specific to GAD, and adding behavioural criteria could clarify the concept of chronic worry for clinicians and enhance the reliability of the diagnosis. The influence of the proposed changes on the prevalence and severity of cases is examined. Method: Data from a national survey and from a clinical data set were used to quantify the effect of the proposed changes. Results: Reducing the duration from 6 to 3 months and removing the clinical significance criterion raised the prevalence of GAD, whereas revising the associated symptoms and adding behavioural symptoms reduced the prevalence. With all the new options implemented, although the prevalence of the diagnosis rose by 9%, it was associated with similar levels of distress and impairment as DSM-IV cases. Conclusions: There is preliminary evidence that the proposals may increase the prevalence of GAD but may not influence the severity of cases. The clinical utility, reliability and validity of the diagnosis remains to be established.

The Worry Behaviors Inventory: Assessing the behavioral avoidance associated with generalized anxiety disorder.

BACKGROUND Understanding behavioral avoidance associated with generalized anxiety disorder (GAD) has implications for the classification, theoretical conceptualization, and clinical management of the disorder. This study describes the development and preliminary psychometric evaluation of a self-report measure of avoidant behaviors associated with GAD: the Worry Behaviors Inventory (WBI). METHODS The WBI was administered to treatment-seeking patients (N=1201). Convergent validity was assessed by correlating the WBI with measures of GAD symptom severity. Divergent validity was assessed by correlating the WBI with measures of general disability and measures of depression, social anxiety and panic disorder symptom severity. RESULTS Exploratory and confirmatory factor analyses supported a two-factor structure (Safety Behaviors and Avoidance). Internal reliability was acceptable for the 10-item WBI scale (α=.86), Safety Behaviors (α=.85) and Avoidance subscales (α=.75). Evidence of convergent, divergent, and discriminant validity is reported. WBI subscales demonstrated differential associations with measures of symptom severity. The Safety Behaviors subscale was more strongly associated with GAD symptoms than symptoms of other disorders, whereas the Avoidance subscale was as strongly correlated with GAD severity as it was with depression, social anxiety and panic disorder severity. LIMITATIONS Structured diagnostic interviews were not conducted therefor validity analyses are limited to probable diagnoses based on self-report. The cross-sectional design precluded examination of the WBIs temporal stability and treatment sensitivity. CONCLUSIONS Preliminary evidence supports the use of the WBI in research and clinical settings and may assist clinicians to identify behaviors that are theorized to maintain GAD and that can be targeted during psychological treatment.

Psychological distress across the lifespan: examining age-related item bias in the Kessler 6 Psychological Distress Scale

BACKGROUND Old age respondents may differ systemically in their responses to measures of psychological distress over and above their actual latent distress levels when compared to younger respondents. The current study aimed to investigate the potential for age-related bias(es) in the Kessler 6 Psychological Distress Scale (K6) items. METHODS Data from the 2007 Australian National Survey of Mental Health and Wellbeing were analyzed using Item Response Theory to detect the presence of item bias in each of the K6 items. The potential for item bias was assessed by systematically comparing respondents classed as young (16-34 years), middle aged (35-64 years), and old aged (65-85 years). The significance and magnitude of the item bias between the age groups was assessed using the log-likelihood ratio method of differential item functioning. RESULTS After statistical adjustment, there were no biases of significant magnitude influencing the endorsement of K6 items between young and middle-aged respondents or between middle-aged and old age respondents. There was a bias of significant magnitude present in the endorsement of the K6 item addressing levels of fatigue between young and old age respondents. CONCLUSIONS Despite the identification of significant item bias in the endorsement of K6 items between the age groups, the magnitude and influence of the bias on total K6 scores is likely to have little influence on the overall interpretation of group data when comparing psychological distress across the lifespan. Researchers should be cautious, however, when examining individual levels of fatigue related to psychological distress in older individuals.

The Psychometric Properties of the Kessler Psychological Distress Scale (K6) in a General Population Sample of Adolescents.

The 6-item Kessler Psychological Distress Scale (K6; Kessler et al., 2002) is a screener for psychological distress that has robust psychometric properties among adults. Given that a significant proportion of adolescents experience mental illness, there is a need for measures that accurately and reliably screen for mental disorders in this age group. This study examined the psychometric properties of the K6 in a large general population sample of adolescents (N = 4,434; mean age = 13.5 years; 44.6% male). Factor analyses were conducted to examine the dimensionality of the K6 in adolescents and to investigate sex-based measurement invariance. This study also evaluated the K6 as a predictor of scores on the Strengths and Difficulties Questionnaire (SDQ; Goodman, 1997). The K6 demonstrated high levels of internal consistency, with the 6 items loading primarily on 1 factor. Consistent with previous research, females reported higher mean levels of psychological distress when compared with males. The identification of sex-based measurement noninvariance in the item thresholds indicated that these mean differences most likely represented reporting bias in the K6 items rather than true differences in the underlying psychological distress construct. The K6 was a fair to good predictor of abnormal scores on the SDQ, but predictive utility was relatively low among males. Future research needs to focus on refining and augmenting the K6 scale to maximize its utility in adolescents. (PsycINFO Database Record