Drug treatments for schizophrenia: pragmatism in trial design shows lack of progress in drug design

Abstract

Aims. The introduction of second generation antipsychotic (SGA) medication over a decade ago led to changes in prescribing practices; these drugs have eclipsed their predecessors as treatments for schizophrenia. However, the metabolic side effects of these newer antipsychotics have been marked and there are increasing concerns as to whether these novel drugs really are superior to their predecessors in terms of the balance between risks and benefits. In this article, we review the literature regarding comparisons between first generation antipsychotic (FGA) and SGA in terms of clinical effectiveness. Methods. Large (n>150) randomized-controlled trials (RCTs) comparing the effectiveness (efficacy and side effects) of FGA and SGA medications other than clozapine were reviewed, as were meta-analyses that included smaller studies. Results. The superiority in efficacy and reduced extrapyramidal side effects (EPSE) of SGAs is modest, especially when compared with low-dose FGAs. However, the high risk of weight gain and other metabolic disturbances associated with certain SGAs such as olanzapine is markedly higher than the risk with FGAs at the doses used in the trials. Conclusions. The efficacy profiles of various FGAs and SGAs are relatively similar, but their side effects vary between and within classes. Overall, large pragmatic trials of clinical effectiveness indicate that the care used in prescribing and managing drug treatments to ensure tolerability may be more important than the class of drug used.