Co-morbid substance misuse in psychiatric patients: prevalence and association with length of inpatient stay.

Improved management of mental illness with co-morbid substance misuse is an important clinical objective. This study aimed to assess the prevalence of substance misuse in psychiatric inpatients, and to examine the relationship between alcohol misuse and length of hospital admission. A prevalence study conducted over four months, examined rates of co-morbid substance misuse in patients admitted for psychiatric inpatient care. Demographic details and length of hospital stay were collected for all patients and those who gave informed consent were screened for levels of alcohol and substance misuse. Two hundred and thirty-eight patients were admitted during the study period in which 178 (74.8%) consented to take part in the study. A group of 44 (50.6%) men and 26 (29.2%) women were screened positive for alcohol misuse (chi(2) = 8.7, P = 0.003). Cannabis use was acknowledged by 31 (35.2%) men and 10 (11.2%) women (chi(2) = 13.5, P < 0.0001). Presence of co-morbid alcohol misuse was associated with a significantly shorter hospital admission (z = 3.34, P = 0.0008). Co-morbid substance misuse (including alcohol) was reported significantly more frequently by men than women. Overall, patients with co-morbid alcohol misuse had shorter hospital admissions, suggesting different patterns of presentation and progress in hospital. Hospital admission presents an opportunity to identify substance misuse and evaluate treatments for co-morbid conditions within a safe environment.