Depot antipsychotic medication is a major component of the maintenance treatment of schizophrenia, but it is still not clear what constitutes an appropriate dose. A number of studies comparing low with standard doses of depot antipsychotic medication on a variety of outcome meas ures have been published in the last decade. A review of these studies indicates that, compared to standard-dose treatment, low- dose medication tends to improve psychosocial function and reduce the frequency of side effects but may result in an in crease in positive symptoms. In such cases, a temporary increase in dose appears to control symptoms and terminate relapse episodes. An explanation of the relative efficacy of low-dose treatment may be derived from recent work in radioreceptor ligand binding.