What do we know? Process analysis and the search for a better understanding of Project MATCH's anger-by-treatment matching effect

OBJECTIVE: A consistent matching result from Project MATCH was the impact of patient trait anger on the effectiveness of alcohol treatments. Despite that finding, subsequent work failed to identify mechanisms underlying the effect. The present study examined a potential mediator, therapist directiveness, to determine its relationship with patient anger, treatment modality and drinking outcomes. Method: Observers rated therapist directiveness for 140 patients (70% men) at one MATCH aftercare site. ANOVA was used to test for the interaction between directiveness and patient anger, treatment differences in level of directiveness, the interaction between treatment modality and anger, and directiveness as a mediator of treatment modality effects. RESULTS: A disordinal interaction was found between patient anger and therapist directiveness. Directiveness was associated with worse drinking outcomes among high anger patients and associated with less frequent drinking among low anger patients. Patient anger also interacted with treatment modality. Motivational enhancement therapy (MET) was more effective than cognitive behavioral therapy (CBT) for patients high in anger, whereas the reverse was true for patients low in anger. A lower level of therapist directiveness in MET mediated its superiority over CBT for high anger patients. Twelve-step facilitation therapy (TSF) was comparably effective to MET for high anger patients; it is interesting to note that TSF and MET did not differ in directiveness. CONCLUSIONS: Therapist directiveness is important to consider when working with patients at varying levels of trait anger. Analysis of the therapy process and tests for mediation are critical to further understand active ingredients of psychosocial treatment.