Moreover, olanzapine was found to have an antidepressant effect and would be expected (because of its reduced tendency to cause extrapyramidal symptoms) to be less likely than haloperidol to exacerbate negative symptoms. Thus, it is especially important to conduct analyses that look at schizophrenic patients alone (i.e., excluding patients with schizoaffective disorder) and to look individually at specific positive symptoms (e.g., hallucinations, delusions, paranoia) to document the effect of olanzapine and haloperidol on typical positive symptoms. I have previously reviewed why neuroleptic-responsive patients, typical of those used for prior studies of standard neuroleptics, are not commonly available for current studies (primarily because of shorter hospitalizations) (1). Studies with neuroleptic-responsive schizophrenic subjects would be expensive and complex because of the need to extend hospitalization. However, I think it is important to conduct such studies.