Research is needed to underpin policy and services for patients with comorbidity

Evidence from the United States suggests that half of all patients with schizophrenia also have a substance misuse disorder.1 This comorbidity is associated with poor prognosis and heavy use of expensive inpatient care through recurrent “revolving door” admissions.2 The phenomenon has only recently been recognised in the United Kingdom, but one survey of psychotic patients in an inner London district found that 36% misused drugs or alcohol. The same survey observed inpatient admission rates among comorbid patients that were almost double those of patients with psychosis alone.3 This high prevalence, the problems of clinical management,4 and a continued rise in the general rate of drug misuse make comorbidity a major public health issue, and the Department of Health is currently inviting applications for research into the prevalence and pattern of comorbidity.

The term “dual diagnosis” is used increasingly in psychiatric practice to describe this combination of …