Psychoactive substance use diagnoses among psychiatric in-patients

Objective: To estimate the prevalence and possible under-diagnosing of substance use disorders and to consider factors that might influence diagnosing of substance use disorders. Method: Data collected from case records and PSE interviews of psychiatric in-patients from 12 psychiatric departments in Denmark admitted during October 1996 were compared with data from the Danish Psychiatric Register. Results: A substantially lower prevalence of substance use diagnoses were found in the register (26.1%) than in the research data (50.0%). A high prevalence of co-occurrence between substance use disorders and mental disorders other than substance use disorders was found (37.3%). In the majority of cases knowledge of the substance use disorders was present in the case records, although they had not resulted in a diagnosis. Conclusion: The under-diagnosis of substance use disorders is due not only to concealed diagnostic signs and symptoms but also to an underdiagnosis by the psychiatrists, in spite of the fact that information on the substance use was accessible.