Substance use among Danish psychiatric patients: a cross-sectional study

Patients with psychiatric disorders have a greater risk of mortality than the general population. Use or abuse of substances, including alcohol, play a crucial part in this context. Moreover, it is well known that drug use can worsen psychopathology and reduce treatment compliance. However, the magnitude of these problems among Danish psychiatric patients has not been studied previously.

The aim of this study is to investigate substance use among psychiatric patients in the Capital Region of Denmark.

Outpatients from five psychiatric units were asked to complete a questionnaire regarding their use of alcohol and other drugs of abuse. The questionnaire was based on the Alcohol Use Disorder Identification Test (AUDIT), supplemented by questions regarding use of tobacco and illicit drugs. The results were compared with those uses in the general population.

In total, 412 psychiatric patients participated in the study, and 33% had an AUDIT-score ≥8, indicating problematic alcohol use according to the AUDIT guidelines. The mean weekly alcohol intake was 9.7 ± 28.3 standard drinks, and 47% were current smokers with a mean daily use of 19.9 ± 13.8 cigarette equivalents. Compared to the general population, the psychiatric patients had higher odds of being current smokers and having used illicit drugs within the past month. Women with psychiatric disorders were twice as likely to binge drink on a monthly basis. No significant difference was found in the patients' AUDIT scores compared to the general population.

Our findings demonstrate a substantial and problematic use of tobacco and illicit drugs among Danish psychiatric patients, greater than in the general population.