What Makes an Antipsychotic ‘Atypical’?

Summary

Until recently, antipsychotic drugs were assumed to be generally equivalent in terms of efficacy while adverse effects varied along a relative continuum. Particular compounds did not stand out as being qualitatively different. With the introduction of clozapine, discussions of novel or atypical effects began, and now there is debate as to what criteria should be used to define atypicality. I would argue that the term has served a heuristic function, but is no longer useful.