Therapist attitudes and patient outcomes. III. A latent class analysis of therapists

Previous research has reported large differences in treatment results between individual therapists practising the same type of psychotherapy, but little is as yet known about the factors explaining this variation. In previous studies the authors have found associations with therapeutic attitudes as measured by the TASC 2 scales.

A sample of 160 therapists were clustered in a non-parametric latent class (LC) regression modelling of their patients' repeated self-ratings on the SCL-90 across stages in psychotherapeutic treatment. This classification was then explored in relation to the therapists' TASC 2 scores.

Five classes were identified differing widely in terms of the patients' outcome trajectories. Membership in these classes was significantly influenced by the therapists' scores on the TASC 2 scales. The adjustment, neutrality and artistry scales of the TASC 2 were found specifically discriminative. A discriminant analysis confirmed the findings in general. Collectively, the TASC 2 scales were able to assign 56% of the therapists to their correct latent class, in comparison with 20% by chance.

Therapists with a psychoanalytic or eclectic orientation are systematically different in terms of the outcomes they tend to contribute to with their patients. This variation is partly accounted for by differences in their therapeutic attitudes.