ODS is a Naturalistic, Open Label, Non-randomized Follow-up Study on Depression and Related Substance Use Disorders (SUD). Study Targets: Efficacy of Psychosocial Treatment, Pharmacogenetics, Inflammation Related Biomarkers

Participants The participants were recruited in five outpatient clinics and in one psychiatric hospital ward in the South Ostrobothnia hospital district (population 200,000) during 1.10.2009 - 31.10.2013. Patients referred to psychiatric secondary services because of depressive symptoms, anxiety, self destructiveness, insomnia and alcohol or other substance related problems were screened with Beck depression inventory (BDI, version 1A). Patients with BDI score ≥ 17 at the screening phase were recruited in the study. The patients with a likely or verified psychotic disorders (ICD-10, F2*.** diagnosis) or organic brain disease were excluded.

A total of 242 patients were included in the study. Fifty-three (21.9%) patients were hospitalised at baseline. The participants were aged 17-64 years (mean 38.8 years, SD 12.2). Among the recruited were 148 females (61.2%) and 94 males (38.8%). The Mini International Neuropsychiatric Interview 5.0 (MINI) was made at the baseline to 219 patients.

At baseline 203 (84%) patients were prescribed antidepressive medication, 81% of cases either SSRI or SNRI as primary antidepressant). Antipsychotic medication was prescribed to 66 (28%) patients.

At the time of recruitment the participants were divided in two groups based on the AUDIT -score. The patients with baseline AUDIT-score ≥ 11 were categorized as patients with comorbid AUD and therefore dual diagnosis (DD+). The patients with AUDIT ≤ 10 were categorized as (DD-).

The clinical psychiatric evaluation was performed by a psychiatrist or other trained professional using the Mini International Neuropsychiatric Interview 5.0 (MINI). The symptoms of MDD were assessed by the Montgomery-Åsberg Depression Rating Scale (MADRS).