He explained that many clinical trials comparing atypical with typical antipsychotic medications have shown that atypical medications are better tolerated. However, little is known about the comparable efficacy and safety of the atypical antipsychotics, since the few double-blind comparison trials completed have studied only chronic patients.

The study will compare the effectiveness and side effects of three atypical antipsychotic medications for the treatment of schizophrenia, schizophreniform and schizoaffective disorder.

Participants in the 17-month comparison study will receive either olanzapine, quetiapine or risperidone for 52 weeks at no cost. At the end of this time, they may enroll in a four-month extension phase. The U.S. Food and Drug Administration has approved the medications.

The long-term study, during which medications will be carefully monitored, will provide valuable information on the medications' effectiveness as well as the causes for discontinuation, Reimherr said.

Individuals who are experiencing their first psychotic episode and who have not been treated with antipsychotic medication for more than 16 weeks may qualify to participate.

Participants must be between the ages of 16-40, and must have experienced psychotic symptoms lasting at least one month but not more than five years.

Participants will receive regular visits with clinic psychiatrists, a battery of assessments and a full physical examination and laboratory studies. They will be reimbursed for travel.