Dose–effect relationship data suggest that short-term psychotherapy is insufficient for many patients with chronic distress or personality disorders (complex mental disorders).
To examine the comparative efficacy of long-term psychodynamic psychotherapy (LTPP) in complex mental disorders.
We conducted a meta-analysis of controlled trials of LTPP fulfilling the following inclusion criteria: therapy lasting for at least a year or 50 sessions; active comparison conditions; prospective design; reliable and valid outcome measures; treatments terminated. Ten studies with 971 patients were included.
Between-group effect sizes in favour of LTPP compared with less intensive (lower dose) forms of psychotherapy ranged between 0.44 and 0.68.
Results suggest that LTPP is superior to less intensive forms of psychotherapy in complex mental disorders. Further research on long-term psychotherapy is needed, not only for psychodynamic psychotherapy, but also for other therapies.
(Reprinted with permission from the British Journal of Psychiatry 2011;199:15–22)