The influence of hazardous drinking on psychological functioning, stress and sleep during and after treatment in patients with mental health problems: a secondary analysis of a randomised controlled intervention study.

Objectives Hazardous drinking could negatively affect health and lead to alcohol use disorders, but it is unclear how hazardous drinking affects treatment outcomes of depression and anxiety and stress related mental health problems. The aim of this study was to examine whether hazardous drinking, measured by Alcohol Use Disorders Identification Test-Consumption (AUDIT-C), influences the outcomes of repeated assessments of psychological functioning (Outcome Questionnaire-45), stress (Perceived Stress Scale) and sleep (Karolinska Sleep Questionnaire), during and after treatment in patients with mental ill health. Methods The study was conducted within REGASSA, a randomised controlled trial aimed at comparing Internet-based cognitive behaviour therapy and physical exercise with treatment as usual on primary care patients with mental ill health. The study involved 871 participants who completed the AUDIT at baseline and who were assessed repeatedly during and after treatment on psychological functioning, stress and sleep by interactive voice response, a computerised, automated telephone technology. Results At baseline, hazardous drinkers were more depressed and had lower scores on psychological functioning than non-hazardous drinkers, while there were no differences on stress and sleep. During the follow-ups, hazardous drinking negatively influenced perceived stress, that is, hazardous drinkers seemed to have less treatment effect on stress, and the results remained after controlling for depression. There were no differences during the follow-ups regarding psychological functioning and sleep. Conclusions Hazardous drinking negatively influenced perceived stress. The findings of the study emphasise the importance of screening for alcohol habits in mental ill-health patients, since risky drinking may affect the outcomes of treatment.