Preliminary work in the area of first-episode psychosis in a small (n=22) open-label trial suggested that risperidone was effective in ameliorating both positive and negative symptoms as well as possibly improving cognitive function . Included in this study were treatment-naive patients with schizophrenia with episodes of less than five years on average. A more precise estimate of the value of risperidone in first-episode psychosis is anticipated when the longitudinal, randomized, controlled trial of risperidone versus haloperi-dol in this population is completed.
Altogether, risperidone has extensive clinical trials and postmarketing experience. It is effective in patients with chronic schizophrenia and is associated with fewer EPSs than haloperidol. Its value in first-episode psychosis and in treatment-resistant schizophrenia requires further investigation to determine its actual merits in these patient subgroups. Long term effectiveness and safety data, specifically evaluating rates of relapse and TD, are also inadequate. Due to its limited anticholinergic effects, risperidone is favoured in the management of elderly patients with chronic psychosis. buy asthma inhaler
Olanzapine is structurally similar to clozapine without the risk of agranulocytosis. It has been shown to be at least as effective as haloperidol for positive symptoms with greater improvement of negative symptoms . However, the advantage for negative symptom improvement is small and of questionable clinical importance. A recent 28-week comparison of olanzapine with risperidone (n=339) suggested advantages of olanzapine regarding negative symptoms, overall response rate and stability of response. Again, the difference in negative symptom improvement is not meaningful clinically. The incidence of EPS, hyperprolactinemia and sexual dysfunction were less and weight gain was greater in the olanzapine group. Improvement in mood symptoms in this trial implied that olanzapine may be useful for depressive symptoms; however, further work is needed in this area before using olanzapine for this indication.