Reappraising the link between peritraumatic dissociation and PTSD symptom severity: evidence from a longitudinal study of community violence survivors

Cross-lagged panel analysis of longitudinal data collected from young adult survivors of community violence was used to examine the relationship between recall of peritraumatic dissociation and posttraumatic stress disorder (PTSD) symptom severity. Recollections of peritraumatic dissociation assessed within days of exposure differed from recollections measured at 3- and 12-month follow-up interviews. Peritraumatic dissociation was highly correlated with PTSD symptoms within each wave of data collection. Baseline recollections of peritraumatic dissociation were not predictive of follow-up PTSD symptom severity after controlling for baseline PTSD symptom severity. This pattern of results replicates previous work demonstrating a correlation between peritraumatic dissociation and subsequent symptom severity. However, findings are not consistent with the prevailing view that peritraumatic dissociation leads to increased PTSD symptom severity.     

A unified approach to exploratory factor analysis with missing data,nonnormal data,and in the presence of outliers

Factor analysis is regularly used for analyzing survey data. Missing data, data with outliers and consequently nonnormal data are very common for data obtained through questionnaires. Based on covariance matrix estimates for such nonstandard samples, a unified approach for factor analysis is developed. By generalizing the approach of maximum likelihood under constraints, statistical properties of the estimates for factor loadings and error variances are obtained. A rescaled Bartlett-corrected statistic is proposed for evaluating the number of factors. Equivariance and invariance of parameter estimates and their standard errors for canonical, varimax, and normalized varimax rotations are discussed. Numerical results illustrate the sensitivity of classical methods and advantages of the proposed procedures.This project was supported by a University of North Texas Faculty Research Grant, Grant #R49/CCR610528 for Disease Control and Prevention from the National Center for Injury Prevention and Control, and Grant DA01070 from the National Institute on Drug Abuse. The results do not necessarily represent the official view of the funding agencies. The authors are grateful to three reviewers for suggestions that improved the presentation of this paper.     

Acquired equivalence and distinctiveness of cues: II. Neural manipulations and their implications

Neural manipulations were used to examine the mechanisms that underlie the acquired equivalence and distinctiveness of cues in rats. Control rats and those with excitotoxic lesions of either the hippocampus (HPC) or entorhinal cortex (EC) acquired the following conditional discrimination: In Contexts A and B, Stimulus X-->food and Stimulus Y-->no food, and in Contexts C and D, Y-->food and X-->no food. Rats then received many food pellets in A but not in C. After this treatment, control rats showed more magazine activity in B than in D--an acquired equivalence-distinctiveness effect. This effect was also evident in HPC rats but not in EC rats. These results indicate that changes in stimulus distinctiveness are dissociable from the process of conditional learning.     

The accuracy of abstracts in psychology journals

This article provides an empirically supported reminder of the importance of accuracy in scientific communication. The authors identify common types of inaccuracies in research abstracts and offer suggestions to improve abstract-article agreement. Abstracts accompanying 13% of a random sample of 400 research articles published in 8 American Psychological Association journals during 1997 and 1998 contained data or claims inconsistent with or missing from the body of the article. Error rates ranged from 8% to 18%, although between-journal differences were not significant. Many errors (63%) were unlikely to cause substantive misinterpretations. Unfortunately, 37% of errors found could be seriously misleading with respect to the data or claims presented in the associated article. Although deficient abstracts may be less common in psychology journals than in major medical journals (R. M. Pitkin, M. A. Branagan, & L. F. Burmeister, 1999), there is still cause for concern and need for improvement.     

The Role of Referent and Expert Power in Mutual Help

This study explored the roles of referent power (i.e., influence based on sense of identification) and expert power (i.e., influence based on knowledge and expertise) in Schizophrenics Anonymous (SA), a mutual-help group for persons experiencing a schizophrenia-related illness. The study describes SA participants' experience of referent and expert power with SA members, SA leaders, and with mental health professionals. It also examines whether or not referent and expert power ascribed to fellow SA participants predicts the perceived helpfulness of the group. One hundred fifty-six SA participants were surveyed. Participants reported experiencing higher levels of referent power with fellow SA members and leaders than with mental health professionals. They reported higher levels of expert power for mental health professionals and SA leaders than for SA members. The respondents' ratings of their SA group's helpfulness was significantly correlated with ratings of referent and expert power. Although expert power was the best independent predictor of helpfulness, a significant interaction between referent and expert power indicated that when members reported high referent power, expert power was not related to helpfulness. These results are interpreted to suggest that there are multiple forms of social influence at work in mutual help.     

Dimensional complexity and power spectral measures of the EEG during functional versus predicative problem solving

Electroencephalograms were recorded in 22 men while solving tasks of visual-pattern completion and during mental relaxation. They were primed (by foregoing trials) to solve these tasks either in a predicative or functional mode of thinking. Predicative thinking required that in order to complete the pattern the subject had to get involved with the logic of the static structure of the pattern and therefore had to recognize the recurrence of certain features of the elements (e.g., shape, color, and size). Functional thinking required involvement in a dynamic reading of the logic of the pattern and therefore to search for operations and actions to be performed on the pattern elements (e.g., pushing, mirroring, and rotating). The EEG complexity during predicative thinking decreased in comparison to functional thinking and mental relaxation, with this reduction being most pronounced over the right parietal cortex. A reduction in dimensional complexity during functional thinking as compared to mental relaxation, which was concentrated over the left central cortex, although significant, was less clear. The reduced EEG complexity during predicative thought, dominant over the right hemisphere, could reflect increased competitive inhibition among respective cortical neuron assemblies in association with the visual analysis of static element features, converging upon those predicates relevant for the solution.     

Childhood Gender Nonconformity and Body Dissatisfaction in Gay and Heterosexual Men

Although researchers have long hypothesized a relation between gender role orientation (i.e., masculinity and femininity) and body dissatisfaction, findings have been inconsistent. The current study employed a measure of recalled childhood gender nonconformity to examine gender role behaviors in association with body dissatisfaction among an ethnically diverse (76% Caucasian, 2% African American, 8% Asian, and 16.4% Hispanic American) group of predominantly college-aged males of both homosexual (n = 129) and heterosexual (n = 52) orientation. Consistent with past research, gay males reported more body dissatisfaction and recalled more childhood gender atypical behaviors (e.g., disliking athletics, playing with dolls). Group differences in body dissatisfaction, however, disappeared when childhood gender nonconformity was statistically controlled, suggesting childhood atypical gender role behavior may place males at greater risk for adult body dissatisfaction. A within-group analysis also found that a high feminine subtype of gay males had greater body dissatisfaction than less feminine subtypes had. Results support the assertion that gender role behaviors may contribute to body dissatisfaction among gay males.     

The role of mental relaxation in experimental desensitization

Certain evidence indicates that training in peripheral muscle relaxation is not an essential factor in the successful experimental desensitization of phobias. Rachman (1968) has suggested that a sense of calmness or mental relaxation is the necessary component and that all the preliminary training techniques leading to successful desensitization, have, as the basis for their success, the inadvertent induction of this state of mental calmness. The direct induction of mental relaxation then, ought to be at least as effective an adjunct to desensitization as training in muscle relaxation. Using spider phobia as the target behaviour, the present study compared the effectiveness of (a) hierarchy presentation paired with deep muscle relaxation; (b) hierarchy presentation paired with instructions to feel calm and relaxed and alternated with imagining a pleasant scene; (c) a combination of these two procedures paired with hierarchy presentation; and (d) a placebo control procedure. The treatment groups all improved significantly more than controls and there there were no differences between treatments. The results were seen as offering strong support of Rachman's position. Both theoretical and practical implications of the results are discussed with consideration being given to the nature of “mental calmness”.