Objectives To examine the associations between socio-economic position (SEP) and the onset of psychiatric work disability, return to work and recurrence of disability.

Methods Prospective observational cohort study (1997–2005) including register data on 141 917 public-sector employees in Finland. Information on International Classification of Diseases, 10th Revision diagnosis-specific psychiatric work disability (≥90 days) was obtained from national registers.

Results During a mean follow-up of 6.3 years, 3938 (2.8%) participants experienced long-term psychiatric work disability. Of these, 2418 (61%) returned to work, and a further 743 (31%) experienced a recurrent episode. SEP was inversely associated with onset of disability owing to depressive disorders, anxiety disorders, personality disorders, schizophrenia and substance-use disorders. No association was found between SEP and disability owing to bipolar disorders or reaction to severe stress and adjustment disorders. High SEP was associated with a greater likelihood of a return to work following depressive disorders, personality disorders, schizophrenia and substance-use disorders, but not bipolar disorders, anxiety disorders or reaction to severe stress and adjustment disorders. Low SEP predicted recurrent episodes of work disability.

Conclusions High SEP is associated with lower onset of work disability owing to mental disorders, as well as return to work and lower rates of recurrence. However, the socio-economic advantage is diagnosis-specific. SEP predicted neither the onset and recovery from disability owing to bipolar disorders and reaction to severe stress and adjustment disorders, nor recovery from disability owing to anxiety disorders. SEP should be taken into account in the attempts to reduce long-term work disability owing to mental disorders.