Impact of prepulse characteristics on the detection of sensorimotor gating deficits in schizophrenia.

Schizophrenia patients have prominent deficits in information processing that can be detected by measures of prepulse inhibition (PPI) of the startle response. Deficient PPI in schizophrenia is thought to reflect a failure of brain-based information 'protective' mechanisms that normally inhibit responsivity for 30-500ms after a weak prepulse stimulus. The relationship between specific prepulse stimulus characteristics and PPI deficits in this study was examined in 31 schizophrenia patients and 34 normal comparison subjects. Schizophrenia patients had overall deficits in PPI across four conditions where the prepulse was either discrete (abrupt) or continuous (sustained) and consisted of either white noise or a pure tone. On inspection and analysis of the data, it appears that the white noise conditions, rather than tone conditions, account for the group differences. Thus, the discrete white noise prepulse was most effective in eliciting PPI deficits, resulting in a large effect size between groups (d=0.85; P<0.01). Deficits in information-protective mechanisms in schizophrenia may be differentially sensitive to specific stimulus characteristics; this observation may be relevant both to the neurobiology of information processing deficits in schizophrenia and to the methodologies for studying these deficits experimentally.

Effects of sex and sex roles on the perceived maladaptiveness of DSM-IV personality disorder symptoms.

This study investigated the influence of sex on the perceived maladaptiveness of DSM-IV personality disorder criteria based on previous findings that inconsistency of symptoms with sex roles affects the perception of personality disorder symptoms. The effects of rater characteristics (i.e., sex, sex role) were also examined. A total of 161 undergraduates (65 men, 96 women) rated the diagnostic criteria according to how maladaptive they were for males (male condition), females (female condition), or without regard to sex (neutral condition that served as a baseline) using a 7-point scale. Participants' sex role was determined using the Bem Sex Role (1981a) Inventory. Dependent and depressive personality disorder criteria (trend for borderline) were rated more maladaptive for females than males, whereas obsessive-compulsive personality disorder criteria were rated more maladaptive for males than females. Participant sex and sex role had little or no significant effects on the ratings. Results are compared with those of previous research. Methodological issues and implications for the diagnosis of personality disorders are discussed.

Relative size of the literatures for psychopathological disorders: number of articles pertaining to DSM-IV diagnostic categories.

A computerized search of the 1991-1997 PsycLIT database was used to quantify the size of the literature for each of the DSM-IV mental disorders. The search included DSM-IV/IIIR diagnoses and alternative terms for the disorders to provide a complete assessment. Generally it was found that major disorders and those with neurophysiological components were investigated a great deal (there were over 10,000 articles for both major depression and schizophrenia) while there were few articles concerning rare or newly introduced disorders. Within diagnostic groups certain disorders received the preponderance of research attention. Factors related to the degree to which a mental disorder is investigated are discussed. These findings should stimulate consideration of whether clinical research is directing its efforts in a way that best promotes understanding of the nature and treatment of mental disorders.

Neuropsychological functioning in patients with borderline personality disorder.

Although results have been variable, studies suggest that individuals with borderline personality disorder (BPD) exhibit cognitive deficits suggestive of frontal- and temporal-lobe dysfunction. Patients diagnosed with BPD (n = 18) using two structured interviews, and who were carefully screened for neurological and substance-use disorders, were compared to depressed patients (n = 18) and a nonpsychiatric control group (n = 18) on a series of neuropsychological tasks. The role of emotion on cognitive functioning was assessed by including emotional stimuli and interference on several of the tasks. Little support was found for the neurobehavioral hypothesis of BPD. The BPD group performance did not differ from the normal group on most tasks of executive functioning or memory, and the introduction of emotional stimuli did not impair performance. The depressed group performed less effectively than the other groups. Reasons for variable findings and factors affecting the cognitive functioning of patients with BPD are discussed. There may be considerable heterogeneity in the cognitive functioning of BPD patients, with those exhibiting significant cognitive deficits comprising only a subgroup.

Sex differences in sensorimotor gating of the human startle reflex: all smoke?

RATIONALE: A recent report described sex differences in the effects of nicotine use and withdrawal on prepulse inhibition of acoustic startle (PPI), but no sex differences in PPI in non-smokers. OBJECTIVE: To determine whether previously reported male>female acoustic PPI reflect sex differences in smoking effects on PPI, rather than simple sex differences in the regulation of PPI. A retrospective analyses of >600 carefully screened normals tested over the past 12 years was completed. RESULTS: Male>female acoustic PPI was detected in analyses that included: 1) all subjects; or 2) self-declared non-smokers. CONCLUSIONS: Sex differences in PPI cannot be accounted for by smoking history, because they are present across a large sample of non-smoking normal controls.

Barron's Ego Strength Scale and Welsh's Anxiety and Repression Scales: a comparison of the MMPI and MMPI-2.

In this study we examined the comparability of the Ego Strength (Es), Anxiety (A), and Repression (R) scales, and Welsh's (1965) classification of scores on the A and R scales into nine categories, on the Minnesota Multiphasic Personality Inventory (MMPI) and MMPI-2. Undergraduate students (65 women, 65 men) completed the MMPI and MMPI-2, in counterbalanced order, 1 week apart. There was high agreement between MMPI and MMPI-2 for the A scale, moderately high agreement for the Es scale, and a moderate level of agreement for the R scale, but little consistency in Welsh's categorization of A and R scores.

Symptoms of prototypic patients with passive-aggressive personality disorder: DSM-IIIR versus DSM-IV negativistic.

This study examined features of patients that clinicians identified as good examples of Passive-Aggressive Personality Disorder to identify core features of the disorder and to determine which set of criteria (DSM-III-R, two definitions in the DSM-IV Options Book, or DSM-IV Negativistic) best characterized the identified patients. A national sample of licensed psychologists (N = 68) identified a patient who (based on symptoms) was a good example of Passive-Aggressive Personality Disorder. They then rated the patient on a symptom checklist composed of the Passive-Aggressive and Negativistic criteria, as well as other personality-disorder symptoms that overlap with Passive-Aggressive. Clinicians identified patients they considered exemplars for Passive-Aggressive Personality Disorder, and there was moderate consensus about their characteristic symptoms. DSM-III-R symptoms received the highest ratings, and there was little overlap with other personality disorders. Principal-component factor analysis suggested that a general pattern of passive resistance, along with a behavioral manifestation of procrastination and a second group of symptoms suggesting interpersonal difficulties, were the features of these passive-aggressive patients. More male patients were identified as good examples of the disorder, and female patients presented a more heterogeneous diagnostic picture. Implications and directions for future research are discussed, including the need to integrate research findings from the differing perspectives on personality disorders.

Information processing deficits of schizophrenia patients: relationship to clinical ratings, gender and medication status.

Information processing deficits were explored in a large cohort of schizophrenia patients (N = 125) and non-psychiatric subjects (N = 52). Gender, medication status and symptom factors were assessed relative to measures of performance in critical stimulus duration (CSD), visual backward masking (VBM) and auditory reaction time (RT) paradigms. Schizophrenia patients exhibited significant impairments in measures of CSD, VBM and both RT speed and RT set. Females in both groups had inflated CSDs relative to males. Female schizophrenia patients showed slower RTs and elevated RT set scores, but comparable VBM performance, when compared to males. This gender difference was not observed in the non-psychiatric subjects. To test the hypothesis that impaired performance in the VBM and RT paradigms would be related to negative symptoms and thought disorder, regression analyses were performed using factor scores derived from a factor analysis of SANS and SAPS items that generated three symptom factors: negative, disorganized, and reality distortion. Significant variance in performance on VBM and RT measures was accounted for only by the negative symptom factor. We conclude that VBM and RT assess information processing deficits in schizophrenia patients that are more related to the negative versus positive or disorganized symptoms of schizophrenia. It is possible that VBM and RT share overlapping or interacting neural substrates.

Positive symptoms of psychosis in posttraumatic stress disorder.

The possible presence of hallucinations and delusional thoughts in posttraumatic stress disorder (PTSD) was investigated. Other symptom clusters were also assessed in order to further clarify the nature of PTSD. Twenty combat veterans with PTSD were compared to 18 combat veterans without PTSD on symptom rating scales. The subjects with PTSD exhibited a greater degree of depression, anxiety, agitation, anhedonia, and positive symptoms of psychosis than the comparison group. Specifically, the PTSD group manifested increased hallucinations, delusions, and bizarre behavior. Some of these positive symptoms did not appear to be due to reexperiencing of the trauma. The groups were not significantly different on indices of mania, thought disorder, or inertia. The clinical and diagnostic implications of the results are discussed. A diagnosis of PTSD should be considered with patients who have positive symptoms in the absence of thought disorder.

Amphetamine on Rorschach measures in normal subjects.

Twenty-two normal undergraduate men were administered either d-amphetamine (0.2 mg/kg or 0.4 mg/kg) or placebo in a double-blind, counterbalanced design. The test sessions were exactly three weeks apart and included, among other measures, the Rorschach test. Rorschach anxiety and thought disorder variables were measured under drug and placebo conditions. The results suggest that amphetamine causes an increase in Rorschach anxiety indices but does not elevate Rorschach indices of thought disorder. The observed dissociation of anxiety and thought disorder on the Rorschach has implications for the role of the Rorschach in studying anxiety disorders and schizophrenic disorders.

Wisconsin Card Sorting Test deficits in chronic paranoid schizophrenia. Evidence for a relatively discrete subgroup?

Some, although not all, researchers have reported dramatically increased numbers of perseverative responses on the Wisconsin Card Sorting Test (WCST) in schizophrenic patients compared to normal comparison subjects. The current study was designed to further explore the nature of possible WCST deficits in a group of paranoid schizophrenic patients compared to normal and psychiatric comparison subjects. In the current study, schizophrenic patients had significantly greater numbers of perserverative responses on the WCST than the comparison groups. The sample of patients with schizophrenia appeared to be characterized by a non-Gaussian distribution of perseverative responses on the WCST. WCST-impaired and WCST-nonimpaired schizophrenic subgroups were compared on cognitive and symptom measures, and increased perseverative responding was associated with negative symptoms, slowed reaction time, and more hospitalizations. While additional research is necessary to further investigate hypotheses of frontal versus generalized brain dysfunction in schizophrenic patients, WCST impairment seems to be present in a clinically meaningful subgroup of paranoid schizophrenic patients.

Physiological evidence of exaggerated startle response in a subgroup of Vietnam veterans with combat-related PTSD.

One of the diagnostic criteria for posttraumatic stress disorder (PTSD) is an exaggerated startle response; however, this phenomenon has not been verified empirically. The authors compared 20 Vietnam combat veterans with PTSD and 18 combat veterans without PTSD on the eyeblink reflex electromyographic response of the startle reaction. Subjects in both groups who failed to show an eyeblink response to the startle stimuli were eliminated from further analyses. Among the remaining subjects, the 13 with PTSD had a significantly greater startle response amplitude than the 12 control subjects at intermediate intensities of acoustic stimuli. The relationship between startle responsivity and both negative and positive symptoms was also investigated.

Gender weighting of DSM-III-R personality disorder criteria.

This study explored the gender weighting of the diagnostic criteria for personality disorders. Gender weighting was defined in terms of how 33 female and 17 male nonclinicians ranked the diagnostic criteria along a male-female dimension. Although the a priori expectation was that antisocial would be the prototypically masculine personality disorder and histrionic the feminine, the subjects ranked criteria from the sadistic category as the most masculine and those from the dependent category as the most feminine. These results and the subjects' gender weighting of criteria for borderline, obsessive-compulsive, and self-defeating personality disorders are analyzed in detail.

Suggested guidelines for including or excluding categories in the DSM-IV.

A set of guidelines is proposed for the possible inclusion or exclusion of diagnostic categories in the DSM-IV. For possible inclusion, a new category should meet all of the following five guidelines: adequate literature, specified diagnostic criteria, acceptable interclinician reliability, evidence that the criteria forms a syndrome, and differentiation from other categories. For possible exclusion, a category should possess an inadequate literature, extremely low coverage, or evidence of diagnostic bias. None of the exclusionary guidelines would be invoked if the category refers to a demonstrable disease.

The family resemblance hypothesis applied to psychiatric classification.

The prototype model, an alternative to the classical view of classification theory, has recently been advocated for the study of the personality disorders. A central assumption of the prototype model is the family resemblance hypothesis. This hypothesis states that the more features of a category that a patient possesses, the more prototypical the patient is of the category. In previous research, results from applying this hypothesis to psychiatric classification have been mixed. The present study investigates the family resemblance hypothesis by examining the relationship between diagnostic agreement and the number of features in personality disorder cases.

The schizophrenia spectrum: a study of the relationship among the Rorschach, MMPI, and visual backward masking.

Compared 20 Ss within the schizophrenia spectrum and 20 non-schizophrenia spectrum controls in terms of their MMPI and Rorschach performance. Ss also were studied in terms of their ability to identify a briefly exposed visual stimulus when it was followed by a noninformational mask stimulus and when it was not. Ss did not differ on the MMPI or on their ability to identify an unmasked target stimulus. They differed significantly in the number of deviant verbalizations, a special scoring category of the Rorschach. Ss also differed in their ability to identify the briefly exposed stimulus when it was followed by the noninformational mask. Results indicated a relationship among the deviant verbalization, the masking procedure, and the schizophrenia spectrum.