This study investigated the 5-year prevalence, duration and predictors of (1) maintenance pharmacological treatment of major depressive disorder (MDD), (2) temporal patterns of pharmacological and psychosocial treatment attitudes and adherence, (3) predictors of a granted disability pension, and (4) long-term associations and covariation of smoking behavior and MDD with comorbid alcohol use disorder as a potential confounding factor.

The investigated cohort consisted of psychiatric out- and inpatients (N=269) of the Vantaa Depression Study (VDS), a regionally representative, prospective and naturalistic follow-up study. Good adherence to pharmacotherapy in the acute phase independently predicted maintenance treatment. Cluster B personality disorder symptoms predicted a negative attitude and poor adherence, while cluster C symptoms predicted a positive attitude and living alone good adherence to psychosocial treatment. Of psychiatric patients with depression, one-fifth were granted a disability pension within 5 years.

Higher age, personality factors, functional disability, lack of vocational education and comorbid somatic disorder predicted the granting of a disability pension. Smoking patients differed from non-smoking patients with regard to several clinical characteristics (particularly substance use disorders) and personality factors (personality disorders and neuroticism), which may markedly confound research on the impact of smoking.