Personality disorder moderates outcome in short- and long-term group analytic psychotherapy: A randomized clinical trial.

Abstract

In a randomized clinical trial, short- and long-term psychodynamic group psychotherapy (STG and LTG, respectively) schedules were equally effective for the 'typical' patient during a 3-year study period. Although several studies have reported good effects for patients with personality disorders (PD) in diverse forms of psychotherapy, the significance of treatment duration is unclear. Therefore, we tested the hypothesis that PD patients would improve more during and after LTG than STG. A randomized, longitudinal, prospective study contrasting the outcomes during and after short- and long-term dynamic group psychotherapies. One hundred and sixty-seven outpatients with mood disorders, anxiety disorders, or PD were randomized to STG or LTG (respectively, 20 or 80 weekly sessions of 90 min each). Outcome measures are as follows: symptoms (SCL-90-R), interpersonal problems (IIP-C), and psychosocial functioning (GAF split version: GAF-Symptom and GAF-Function). PD pathology (number of PD criteria items) was selected a priori as a putative moderator of treatment effects. Change during the 3-year study period was assessed using linear mixed models. The study was registered at ClinicalTrials.gov as NCT 00021417. Our hypothesis was supported, as patients with PD improved significantly more regarding all outcome variables in LTG than STG. For patients without PD, the rate of change was similar across 3 years; however, the rate of change in symptoms and interpersonal problems was higher in STG during the first 6 months. The effectiveness of LTG is higher for patients with co-morbid PD. Patients without PD do not appear to experience additional gain from LTG. Clinical implications: LTG demonstrates better effectiveness than STG for patients with personality disorder co-morbidity (PD). Patients without PD do not appear to experience additional gain from attending LTG. Correct initial allocation to treatment duration may prevent disruptive breaks in relationships and lead to both human and economic cost savings. Limitations: Trials on mixed diagnostic samples may limit the ability to fully assess change for specific diagnostic groups. Therapists were unable to select patients and compose their own groups. Although this condition might increase the generalizability of the results, it may also have restricted the therapists and the clinical situation inadvertently.