In 2008, Falk Leichsenring, DSc, and Sven Rabung, PhD, published a meta-analysis on the « Effectiveness of Long-term Psychodynamic Psychotherapy » in the Journal of the American Medical Association (JAMA, 2008; 300(13): 1551-1565, doi:10.1001/jama.300.13.1551).
The authors start their enquiry by questioning the controversial status of psychoanalysis and psychodynamic treatment in mainstream psychiatry. Although proof for efficiency of short-term psychodynamic therapy has already been acquired for specific disorders, long-term therapy seemed unable to provide anything better than disputed proof.
Leichsenring and Rabung claim to provide this lacking evidence for outcome effectiveness of long term psychodynamic psychotherapy. Their meta-anlaysis of outcome studies published between January 1960 and May 2008 shows that « comparative analyses of controlled trials, LTPP showed significantly higher outcomes in overall effectiveness, target problems, and personality functioning than shorter forms of psychotherapy. With regard to overall effectiveness, a between-group effect size of 1.8 […] indicated that after treatment with LTPP patients with complex mental disorders on average were better off than 96% of the patients in the comparison groups (P=.002). According to subgroup analyses, LTPP yielded significant, large, and stable within-group effect sizes across various and particularly complex mental disorders (range, 0.78-1.98). »
Free access to the paper can be found here: http://jama.ama-assn.org/content/300/13/1551.full