Abstract
When comparing the relative effectiveness of different psychological treatment approaches using clinical trials, it is essential to establish fidelity to each manualized therapy, and differentiation between the treatment arms. Yet few psychological therapy trials include details about the assessment of treatment integrity and little is known about the specific techniques used by therapists, or to what degree these techniques are shared or distinct across different therapeutic approaches. The aims of this study were: to establish the fidelity of two established psychological therapies - cognitive-behaviour therapy (CBT) and short-term psychoanalytic psychotherapy (STPP) - in the treatment of adolescent depression; and to examine whether they were delivered with adherence to their respective treatment modalities, and if they could be differentiated from each other and from a reference treatment (a brief psychosocial intervention; BPI). The study also aimed to identify shared and distinct techniques used within and across the three treatments. Audio-tapes (N=230) of therapy sessions, collected as part of a trial, were blind double-rated using the Comparative Psychotherapy Process Scale (CPPS), which includes subscales for cognitive-behavioural and psychodynamic-interpersonal techniques. The treatments were delivered with reasonable fidelity and there was clear differentiation in the use of cognitive-behavioural and psychodynamic-interpersonal techniques between CBT and STPP, and between these two established psychological therapies and BPI. An item-level analysis identified techniques used across all three treatments, techniques that were shared between BPI and CBT, and techniques that were unique to CBT and STPP.