World Psychiatric Association Pharmacopsychiatry Section statement on comparative effectiveness of antipsychotics in the treatment of schizophrenia

Abstract

Data from two major government-funded studies of comparative antipsychotic effectiveness in schizophrenia contradict the widely prevalent belief that the newer second-generation medications are vastly superior to the older first-generation drugs. This has caused uncertainty among patients, clinicians and policy-makers about the relative utility of first- and second- generation antipsychotic agents in its treatment. To reduce confusion and provide a contextual understanding of the new data, the World Psychiatry Association Section on Pharmacopsychiatry comprehensively reviewed the literature on the comparative effectiveness of different antipsychotic treatments for schizophrenia and developed this update. Utilizing data from the approximately 1,600 randomized controlled trials of antipsychotic treatment in schizophrenia, we applied the two indirect and one direct method to comparing the effectiveness of 62 currently-available antipsychotic agents. The subclasses of 51 first-generation and 11 second-generation antipsychotics were both found to be very heterogeneous, with substantial differences in side-effect profiles among members. Second-generation antipsychotic agents were found to be inconsistently more effective than first-generation agents in alleviating negative, cognitive, and depressive symptoms and had a lower liability to cause tardive dyskinesia; these modest benefits were principally driven by the ability of second-generation antipsychotics to provide equivalent improvement in positive symptoms along with a lower risk of causing extrapyramidal side-effects. Clozapine was found to be more efficacious than other agents in treatment-refractory schizophrenia. There were no consistent differences in efficacy among other second-generation antipsychotic agents; if such differences exist, they are likely small in magnitude. Dosing was found to be a key variable in optimizing effectiveness of both first- and second- generation antipsychotic agents. There was enormous individual variability in antipsychotic response and vulnerability to various adverse effects. In contrast to their relatively similar efficacy in treating positive symptoms, there were substantial differences among both first- and second- generation antipsychotic agents with regard to their propensity to cause extrapyramidal, metabolic and other adverse effects; second-generation agents have a lower liability to cause acute extrapyramidal symptoms and tardive dyskinesia along with a tendency to cause greater metabolic side-effects than first-generation agents. Based on these data about the comparative effectiveness of different antipsychotic treatment options, we summarize elements of current best antipsychotic practice for the treatment of schizophrenia and discuss the role of government and the pharmaceutical industry in obtaining and disseminating information which can facilitate best practice.