There are a number of differences between use of antipsychotics in first episode psychosis (FEP) versus in patients who have had psychosis for a longer period. First, effective medication dosage ranges are substantially lower. Second, even with these lower dosages, response rates are considerably higher, with 50-80% of individuals with FEP responding to these treatments. Finally, side effects such as drowsiness and weight gain are much more common. For more information, see this resource.