What Makes an Antipsychotic Atypical?

A flood of new antipsychotics is generating improved treatments for schizophrenia but tangled terminology for clinicians. All of the newer antipsychotics since clozapine have been lumped into a new therapeutic class often referred to as "atypical" (This includes not only risperidone, olanzapine, and quetiapine, but also sertindole (marketed only outside the United States) and ziprasidone (expected to be approved in the United States soon). Lumping all of the new agents together helps to distinguish them as a class from most of the older conventional antipsychotics, which are clearly less tolerated and possibly less effective, especially for negative symptoms. These new agents must distinguish themselves from the older generic agents if they hope to support price premiums.