Acceleration of changes in session impact during contrasting time-limited psychotherapies

Following the suggestion that therapeutic change is accelerated in time-limited psychotherapy, this study investigated the across-session patterns of session impact in the treatments of 117 depressed clients who were randomly allocated to 8 or 16 sessions of cognitive-behavioral (CB) or psychodynamic-interpersonal (PI) therapy. After each session, all clients completed the Session Evaluation Questionnaire and 75 of the clients completed the Session Impacts Scale. Session ratings indicated that sessions were perceived increasingly positively on most impact dimensions (e.g., session depth and smoothness, relationship with the therapist, feelings of understanding and problem solving, postsession positive mood) as treatment progressed. Early in treatment, PI therapy sessions were less smooth (i.e., more tense and uncomfortable) and less focused on problem solving, but PI sessions changed more rapidly than CB sessions on these dimensions, so that later in treatment, sessions of both treatments were equivalently positive. In both treatments, the trend toward more positive sessions was more rapid (i.e., the across-session slope was steeper) in 8-session treatments than in 16-session treatments. Such accelerated changes in session impact may reflect the suggested acceleration of therapeutic change associated with shorter time limits.