Randomized trial on the effectiveness of long-and short-term psychodynamic psychotherapy and solution-focused therapy on psychiatric symptoms during a 3-year follow-up.
Knekt P, Lindfors O, Härkänen T, Välikoski M, Virtala E, Laaksonen MA, Marttunen M, Kaipainen M, Renlund C, Helsinki Psychotherapy Study Group. Psychol Med. 2008 May; 38(5):689-703. Epub 2007 Nov 16.