To review the effects of zotepine compared with placebo for people with schizophrenia or related psychoses.

As secondary objectives, we propose to investigate whether people:

1. with schizophrenia described as 'treatment resistant' differed in their response from those whose illness was not designated as such;
2. having predominantly positive or negative symptoms of schizophrenia were more responsive to zotepine than those without this designation; and
3. experiencing their first episode of schizophrenia differed in their response from those at a later stage of their illness.