Antipsychotic drug treatment is usually started during an acute episode or exacerbation of a pre-existing psychosis. Although the medication has marked therapeutic benefit for most patients, ther is considerable heterogeneity in drug response. A variety of factors may influence this response, but at present we have no well-established predictors which would help targeting specific pharmacological treatments. The continuation of antipsychotic drug treatment to control persistent symptoms and to prevent further exacerbations or relapse has become a mainstay in the long-term treatment of schizophrenia. There are various considerations which come into play in deciding which patients should receive such treatment, at what dose, and for how long. Research in recent years has attempted to identify strategies to minimize the risks associated with long-term treatment (particularly tardive dyskinesia). In addition, other factors influencing long-term outcome have been better studied in combination with controlled drug treatment.