Four symptom dimensions in outpatients with schizophrenia.

Objective: The aim of this study was to assess the dimensional structure of the Positive and Negative Symptoms Scale (PANSS) to identify the psychopathological profiles of outpatients with schizophrenia.

Method: Two hundred and thirty-one persons with schizophrenia (DSM-IV criteria) were randomly selected from a register that included all patients under treatment in 5 mental health care centers in Spain. Patients were evaluated with a sociodemographic and clinical questionnaire, the PANSS, the Disability Assessment Scale short version, and the Global Assessment Functioning Scale. A principal component analysis with oblimin rotation was used to examine the factor structure of the PANSS. Different statistical analyses were done to compare the resulting factors with clinical, disability, and social functioning variables.

Results: Mean age of patients included was 39.6 years and approximately 65% were male. Four principal components, each of them with eigenvalues greater than 1.5, accounted for 56.22% of the variance. After oblimin rotation, these factors were identified as the Negative (32.48%), Excitement (11.29%), Affective (7.45%), and Positive (5.01%) components. Significant positive correlation between age and the negative dimension was found. Also, we observed significant negative correlations between global assessment functioning and negative and positive dimensions. Total disability was significantly positively related to all dimensions.

Conclusion: Positive and negative dimensions are common in all principal component analysis results, but we also found affective and excitement dimensions. The present finding suggests that further investigation of symptom dimensions may help to improve symptom-specific treatments; future research should focus on the design of new treatment programs considering these results.