Since the early 1950s the mainstay of treatment for schizophrenia has been the typical antipsychotics such as chlorpromazine and haloperidol. Although they are effective in controlling voices and delusions for many people with schizophrenia, they have a smaller effect on symptoms such as apathy and social withdrawal. They also have disabling adverse effects such as tremor, stiffness and slowing of movement. The newer drugs, such as olanzapine, are reputed to have fewer adverse motor effects and are as effective, if not more so, than the older drugs. This review examines the randomised controlled trials of olanzapine compared with placebo, typical and atypical antipsychotic drugs.
Most of the studies in this review were either sponsored by or run by the pharmaceutical companies responsible for the marketing of these drugs. Olanzapine seems to be an effective antipsychotic that produces less adverse effects for movement. It does however tend to cause more weight gain than the older drugs. Its effectiveness appears similar to other atypical drugs and it is not markedly beneficial for apathy, demotivation and social withdrawal.