Comorbid alcohol misuse in schizophrenia and severe mental illness is associated with significant clinical, social and legal problems. An epidemiologically informed approach to planning service delivery requires an understanding of which clinical populations are at particularly high risk for alcohol misuse. Most evidence about the prevalence of this comorbidity comes from the USA, Canada and Australia, and, though at a different pace, also from Europe.

A cross-sectional survey design has been used to determine the prevalence In Italy of comorbid drug and alcohol and any - even minor - mental disorders. Staff ratings was used to assess comorbid substance use.

Though overall dual diagnosis prevalence is around 2%, significantly higher rates were found in inner cities. Furthermore significant differences were found between different geographical areas (Northern vs. Centre vs. Southern Italy). Peculiar diagnostic subgroups showed higher risk to develop such comorbid condition, whilst a number of clinical and sociodemographic variables, including area of residence, were associated with the risk to develop a dependence syndrome.

Sampling and assessment procedures are major limitations which might explain the lower rates as compared with the current Anglo-Saxon literature. However, such variability emphasizes also that high comorbid alcohol misuse rates are not necessarily the direct result of biological features inherent in schizophrenia, but that social factors play an important role. Finally, a number of risk factors associated with dual diagnosis could build up an evidence base about the nature of their substance use, providing targeted service planning and policy making.