This study examined client perception of the therapeutic impact of two models of therapy delivered by mental health nurses and clinical psychologists respectively - psychodynamic interpersonal therapy (PIT) and cognitive behavioural therapy (CBT). A non-equivalent groups design was used in order to benchmark results against Llewelyn et al.: one group received PIT and the other received CBT. This design was utilized principally because the research was conducted across two practice settings where randomization was not feasible. We used two intact groups in practice research settings that received the therapies as reported in Llewelyn et al. Sixty-one clients receiving CBT or PIT in practice research settings completed a Helpful Aspects of Therapy form after each session in order to measure client perceptions of helpful and hindering events in therapy. Only two out of the 13 impacts were rated as significantly different. PIT clients reported higher levels of 'awareness' than CBT clients, whereas CBT clients reported higher levels of problem solution than PIT clients. The results replicate Llewelyn et al.'s findings in that clients experienced theoretically different models of therapy as broadly similar in their therapeutic impact. We argue that this provides some support for the influence of 'common' rather than 'specific' factors in psychotherapy effectiveness in mental health nursing.