Long-term studies of antipsychotic drugs in schizophrenia

Studies on long-term efficacy and safety should be a main concern in the evaluation of novel antipsychotics. The present paper is a review of important issues related to the design and performance of such trials. The variability of the natural course of schizophrenia, the variability in treatment response, and the variability of actions of different neuroleptics need to be considered. Long-term studies need to address maintenance of efficacy, prevention of relapse and recurrence, health economics, quality of life and a large number of safety issues in order to get approval for new drug applications and reimbursement on expensive new medicines. Assessment instruments for efficacy, tolerability and safety, need to be supplemented with rating scales for various aspects of psychopathology (positive, negative, deficit symptoms), social and work functioning, drug induced mental side effects, quality of life and accounts of total treatment costs.