The therapeutic alliance in psychotherapy for adolescent depression: Differences between treatment types and change over time.

Although the alliance is usually considered a generic factor common to all therapies, there are theoretical reasons to suspect that the alliance may develop differently in different types of therapies. Yet, in youth psychotherapy little is known about this issue to date. This study investigated whether the mean strength of the alliance, as well as its trajectory over time, differed between three equally effective psychological treatments for adolescent depression. Data were drawn from the *anonymised* study, a randomized controlled trial comparing cognitive-behavioural therapy (CBT) and short-term psychoanalytic psychotherapy (STPP) versus a brief psychosocial intervention (BPI) in the treatment of adolescent depression. Adolescents’ (N=338) and therapists’ (n=159) ratings of the alliance were collected using the Working Alliance Inventory short form (WAI-S) at 6, 12 and 36 weeks after randomization. Data were analysed using multilevel linear models. Results showed that adolescents’ and therapists’ mean alliance ratings differed between treatment types, being highest in CBT, and lowest in the STPP at all time points. Mean therapists’ alliance ratings increased slightly over time in all arms, while mean adolescents’ ratings were stable over time in CBT and BPI, but slightly increased in the STPP group. These findings suggest that the mean strength of the alliance differs between treatment type and future research is required to help pinpoint what factors contribute to these differences and their relationship with treatment outcomes.