Mental disorders are a primary cause of occupational impairments. This study investigated long-term changes in occupational functioning for patients referred to psychotherapeutic treatment at a Danish mental healthcare centre in 2004 and 2005.

We recruited 761 consecutive patients and 15,220 matched-control subjects. Data on number of days per year on sick leave, unemployment, and disability pension were collected from central registries over a 5-year observation period from 2002–2007. Differences in number of days with occupational impairments between and within groups were analyzed with t-test and with ANCOVA one and two year pre-post treatment.

Of the 761 patients, 216 patients did not show up for treatment, while 545 patients completed treatment; 228 responded and 201 did not respond to treatment. Data on treatment response was missing for the remaining 116 patients. Completer patients’ days on sick leave increased significantly from 15.7 days two years before treatment to 23.1 days two years after treatment (p < 0.000) and significant more than the control group (5.4days : 7.5 days). Similar results were found for days on disability pension (p = 0.013). Unemployment did not show any significant change for completer patients compared to the control group (p = 0.569). Variations in results were seen, depending on treatment status as no-show, responder or non-responder.

Patients that received psychotherapeutic intervention showed long-term increases in days on sick leave and disability pension.