Sandra Grochowski

Five factor model of schizophrenia: Replication across samples

In order to examine the effect of neuroleptic medication on the factor structure of schizophrenic symptomatology, 517 DSM-III-R schizophrenic in-patients enrolled in a multicenter phase II drug study were evaluated on their pre-existing neuroleptic at screening on the Positive and Negative Syndrome Scale (PANSS) and after a one-week drug-free period. Separate principal components analyses of the PANSS were done at each time point. PANSS total and component scores were assessed for differences utilizing paired t-tests. Both factor analyses confirmed the five factor model (negative, positive, cognitive, excitement and depression components) explaining 51.7 and 56.2% of the variances at each time point. After medication wash-out psychopathology significantly worsened as measured by total PANSS score and by each of the components. The overall worsening of component scores appeared global and uniform, as evidenced by the fact that at washout, the proportion of individual component scores to total psychopathology remained constant for most components. The lack of change of most components in proportion to the psychopathology total is evidence for the stability of these individual psychopathological dimensions of patients while on and off neuroleptics. The results further support the validity of the five-factor model of schizophrenic psychopathology as measured by the PANSS.

Five-factor Model of Schizophrenia Initial Validation

Schizophrenic psychopathology is heterogeneous and multidimensional. Various strategies have been developed over the past several years to assess and measure more accurately discrete domains of psychopathology, One of the more fruitful strategies to investigate more homogenous domains of psychopathology has been the positive-negative syndrome approach. However, this approach is unable to address a number of important issues. Most schizophrenics present a mixed syndrome; the criteria for what constitutes a positive and negative syndrome are variable; distinguishing primary from secondary negative symptoms can be difficult. In order to address some of these problems, we propose the introduction of a five-syndrome model based on a reanalysis of factor analytic procedures used on 240 schizophrenics assessed with the Positive and Negative Syndrome Scale. We present data on a five-factor solution that appears to best fit the psychopathological data and that is supported by three independent and comparable factor analyses; negative, positive, excitement, cognitive, and depression/anxiety domains of psychopathology give patients their individual mark. Data on internal consistency of the five factors and on initial validation using demographic and clinical variables are presented.

A new five factor model of schizophrenia.

Schizophrenic psychopathology is heterogeneous and multidimensional. Various strategies have been developed over the past several years to assess and measure more accurately discrete domains of psychopathology. One of the more fruitful strategies to investigate more homogenous domains of psychopathology has been the positive-negative syndrome approach. However, this approach is unable to address a number of important issues. Most schizophrenics present a mixed syndrome; the criteria for what constitutes a positive and negative syndrome are variable; distinguishing primary from secondary negative symptoms can be difficult. In order to address some of these problems, we propose the introduction of a five syndrome model based on a reanalysis of factor analytic procedures used on 240 schizophrenics assessed with the Positive and Negative Syndrome Scale (PANSS). We present data on a 5-factor solution which appears to best fit the psychopathological data and which is supported by three independent and comparable factor analyses; negative, positive, excitement, cognitive and depression/anxiety domains of psychopathology give patients their individual mark. Data on internal consistency of the five factors and on initial validation using demographic and clinical variables are presented.

Psychopathology of Schizophrenia: Initial Validation of a 5-Factor Model

Schizophrenic psychopathology is heterogeneous and multidimensional. One of the more fruitful strategies to investigate more homogenous domains of psychopathology has been the positive-negative syndrome approach. However, this approach is unable to address a number of important issues. Most schizophrenics present a mixed syndrome; the criteria for what constitutes a positive and negative syndrome are variable; distinguishing primary from secondary negative symptoms can be difficult. In order to address some of these problems, we propose the introduction of a 5-syndrome model based on a reanalysis of factor-analytic procedures used on 240 schizophrenics assessed with the Positive and Negative Syndrome Scale: A negative, positive, excitement, cognitive and depression/anxiety factor. This 5-factor solution is supported by 4 independent and comparable factor analyses. Data on internal consistency of the 5 factors and on initial validation using demographic and clinical variables are presented.

Clozapine effects on positive and negative symptoms : a six-month trial in treatment-refractory schizophrenics

Fifteen DSM-III-R diagnosed schizophrenics characterized by long-term neuroleptic nonresponse and significant negative symptoms were evaluated with the Positive and Negative Syndrome Scale, a well-operationalized measure of psychopathology, on a baseline neuroleptic and weekly thereafter across 26 weeks of clozapine treatment in order to explore clozapines effect on other domains of schizophrenic psychopathology beyond its effect on positive symptoms. Mean differences from baseline indicated significant improvement on positive, negative, cognitive, excitement, and depression subscales after 12 weeks. Improvement observed after 12 weeks of clozapine treatment reliably predicted scores observed at week 26. There were no further significant improvements on any symptom profile, including positive and negative symptoms, in this long-term, nonresponder group between weeks 12 and 26. Overall, clozapine proved to affect a broad spectrum of discrete and nonoverlapping domains of psychopathology in this schizophrenic sample.

Schizophrenic patients with depression: Psychopathological profiles and relationship with negative symptoms

This study investigates the occurrence of depression and related psychopathological features in chronic schizophrenics and attempts to examine whether depressive symptoms are independent of negative symptoms. We found that 54% of our sample of 240 chronic schizophrenics exhibited moderate to severe depression. Independent t tests showed that those high in depression tended to exhibit significantly more positive symptoms as defined by the Positive and Negative Syndrome Scale (PANSS). Those with high depression do not exhibit significantly worse negative symptoms compared with low depression, clearly differentiating depression from negative symptoms. Results and the relationship to a previous factor-analytic study of schizophrenic symptoms are discussed.

Premature disinhibition of P3 generation in schizophrenia

P300 (P3) is a long-latency cognitive event-related potential (ERP) elicited by relevant target stimuli. P3 was recorded from 11 schizophrenics and 13 normal controls during a cued visual continuous performance task (CPT-AX). Cue-target sequences were presented at short and long interstimulus intervals (ISIs), in order to investigate working memory in schizophrenia. There was no significant between-group difference in P3 amplitude to validly or invalidly cued targets at short ISI. In contrast, P3 amplitude to invalidly cued targets at long ISI was significantly greater in schizophrenics than in controls, suggesting decreased ability to encode or maintain inhibitory representations of stimulus context. P3 amplitude is typically reduced in schizophrenic subjects in the auditory modality, and normal or reduced in the visual modality. This study, which demonstrates a paradoxical P3 increase to targets at long ISI, suggests that P3 impairment in schizophrenia cannot be attributed solely to structural deficits within P3-generator regions.

Problem solving and suicidality among prison inmates: another look at state versus trait

This research examines the relationships between means-ends problem solving and suicidality among adult male prison inmates in light of new evidence based on inpatient and college student populations suggesting that state, rather than trait, vulnerabilities may be responsible for problem-solving deficits and differences. Using the Means-Ends Problem-Solving Procedure (MEPS) with 93 state prison inmates, we found that among inmates with a history of parasuicide, current suicidality did not affect problem-solving performance. We further found that among nonsuicidal inmates, parasuicide history had no effect on problem solving or affect-suicidality measures. Although these results support new research suggesting that trait problem-solving deficits are not causally linked to suicidality, they raise questions about the potentially unique relationships among suicidality, problem solving, depression, and hopelessness in incarcerated populations.

Heterogeneity of serotonergic response in treatment-refractory schizophrenia patients

Oral metachlorophenylpiperazine (m-CPP) as a direct-acting postsynaptic serotonergic agonist was used to study serotonergic dysfunction in treatment-refractory chronic schizophrenia based on the hypothesis that some patients may show central serotonergic hypersensitivity. Seventeen DSM-III-R chronic schizophrenic patients with a history of neuroleptic nonresponse underwent double-blind challenge with oral m-CPP (0.25 mg/kg body weight) and placebo after medication washout: m-CPP significantly elevated both prolactin and cortisol levels as compared to placebo. There was a significant relationship between change in cortisol level and change in psychopathology under m-CPP; a blunted cortisol response was associated with a decrease in total psychopathology, while an increase in cortisol response related to an increase in psychopathology. Similarly, decrease in severity of the activation factor and the hostility factor was associated with a smaller cortisol response in the m-CPP condition. These results point to heterogeneity in central serotonergic sensitivity within the context of different subpopulations of serotonergic receptors.