This monograph arose from a cooperative endeavour between the Mental Health Branch and the Drug Strategy Branch whose concerns were centred on the epidemic comorbidity between psychosis and substance dependence. Data from epidemiological surveys both here and overseas suggests the main burden of concurrent disorders is elsewhere. WHO has argued that, as there are insufficient funds to provide health care to all, we might prioritise diseases of greatest burden and diseases in which there are cost effective treatments. On both grounds the anxiety and affective disorders rank higher than the other mental disorders. Earlier we noted the human tendency to respond to emergencies, to prefer flood mitigation to salinity control. At present our health system struggles to respond to the emergencies posed by substance use and psychosis. Responding to the quieter problem posed by anxiety and affective disorders will be a difficult task.