Factor analysis of symptom dimensions (psychotic, affective and obsessive compulsive symptoms) in schizophrenia

To carryout factor analysis of symptom profile of patients with schizophrenia assessed by using positive and negative syndrome scale (PANSS), Calgary depression rating scale (CDSS), Young mania rating scale (YMRS) and YBOCS checklist.

181 patients of schizophrenia were assessed on PANSS, CDSS, YMRS and YBOCS checklist.

Factor analysis of PANSS yielded 3 factor structure (positive, negative, anxiety). When the items of CDSS were added to the PANSS items, total number of factors increased to 4 with depression emerging as a separate factor. Addition of YMRS to PANSS and CDSS led to emergence of 5 factor model. Further addition of YBOCS checklist led to emergence of a 7 factor model (positive, depressive, obsessive compulsive, negative, manic, anxiety and obsessive compulsive-2), which explained 49.85% variance of the data. Positive symptoms emerged as the factor-1. Depressive symptoms loaded on the factor-2, negative symptoms loaded on to factor-4, manic symptoms loaded onto factor-5 and anxiety symptoms loaded onto factor-6. OC symptoms loaded onto factor 3 and 7.

Present study suggests that when multiple scales are used for assessment of various symptoms of schizophrenia, the symptoms separate out into 7 factors. This finding suggests that clinical assessment of schizophrenia should not be limited to core psychotic symptoms only and structured instruments must be used to elicit other symptoms too while monitoring the clinical picture of patients with schizophrenia.