The study, which looked at four new-generation drugs, called atypical antipsychotics, and one older drug, found that all five blunted the symptoms of schizophrenia, a disabling disorder that affects three million Americans. But almost three-quarters of the patients who participated stopped taking the drugs they were on because of discomfort or specific side effects.

In the doses used in the study, a month's supply of perphenazine costs about $60, compared with $520 for Zyprexa, $450 for Seroquel, $250 for Risperdal and $290 for Geodon, according to Drugstore.com.