There are no randomised clinical trials comparing the outcomes of short- with long-term psychodynamic group psychotherapy.

To compare differences in outcome during and after short-and long-term group psychotherapy.

In total, 167 out-patients with mood, anxiety and personality disorders were randomised to short- or long-term group therapy (20 or 80 weekly, 90 min sessions). Outcome measures were: symptoms (Symptom Checklist 90 – Revised), interpersonal problems (Inventory of Interpersonal Problems – Circumplex) and psychosocial functioning (Global Assessment of Functioning (GAF) split version: GAF-Symptom and GAF-Function). Change over the 3-year study period was assessed using linear mixed models. The study was registered in clinicalTrials.gov as NCT00521417.

Patients in both groups made significant gains. A significantly larger symptomatic change over time was found for long-term compared with short-term therapy, but no significant differences were detected for the three remaining outcome variables. There was a higher number of premature terminations in the long-term (33.3%) compared with the short-term group (8.6%).

Short- and long-term therapy seem equally effective for typical out-patients seeking group psychotherapy, except for symptomatic distress.