Do patients with paranoid and disorganized schizophrenia respond differently to antipsychotic drugs?

Objective: The aim of this study was to compare the differential response to amisulpride in patients with paranoid versus disorganized schizophrenia. Method: We reanalyzed the original data from five different randomized drug trials comparing Brief Psychiatric Rating Scale (BPRS) scores in a database containing 427 paranoid and 296 disorganized patients with schizophrenia. Results: Both the disorganized and the paranoid group showed a substantial improvement of the BPRS total score within the first 4 weeks. In the paranoid group, mean (±SD) BPRS reduction was 16.9 (±14.6) (t = 24.06, df = 426, P < 0.001) and in the disorganized group 17.0 (±15.9) (t = 18.49, df = 295, P < 0.001). An analysis of covariance (ancova) controlling for BPRS at baseline and the influence of different trial protocols showed significant differences between diagnostic groups (F = 13.47, df = 1, P < 0.001), Cohen's D 0.31 (CI = 0.16-0.46). Paranoid patients improved by 4.8 BPRS points more than disorganized patients (adjusted means 18.90 (CI = 17.33-20.37) for the paranoid and 14.1 (CI = 12.04 - 16.11) for the disorganized group. Conclusion: We conclude that amisulpride is effective in disorganized as well as in paranoid schizophrenia, but that symptom reduction in the disorganized subtype is less pronounced.