The effectiveness of short- and long-term psychotherapy on personality functioning during a 5-year follow-up

Only few randomized trials comparing sustained effects of short- and long-term psychotherapies in personality functioning are available. In this study we compared the effects of two short-term therapies and long-term psychodynamic psychotherapy on patients' personality functioning during a 5-year follow-up.

Altogether 326 patients of the Helsinki Psychotherapy Study, with anxiety or mood disorder, were randomly assigned to either short-term psychotherapy of about six months (solution-focused therapy (SFT, n=97) or short-term psychodynamic psychotherapy (SPP, n=101)), or to long-term psychodynamic psychotherapy (LPP, n=128), lasting on average three years. Outcomes in personality functioning (i.e., self-concept, defense style, interpersonal problems, and level of personality organization) were assessed five to seven times using, respectively, questionnaires (SASB, DSQ, IIP) and interview (LPO) during the 5-year follow-up from randomization.

Personality functioning improved in all therapy groups. Both short-term therapies fared better than LPP during the first year of follow-up, by faster improvement in self-concept and decrease in immature defense style. SFT also showed more early reduction of interpersonal problems. However, LPP thereafter showed larger and more sustained benefits than SFT and SPP, through greater changes in self-concept. Additionally, LPP outperformed SFT at the end of the follow-up in IIP and LPO, after adjustment for auxiliary treatment. No differences were noted between the short-term therapies at any measurement point.

Auxiliary treatment was used relatively widely which limits generalization to exclusive use of short- or long-term therapy.

LPP seems to be somewhat more effective than short-term therapies in facilitating longterm changes in personality functioning.