Therapist Effects in Addiction Treatment
A persistent finding in addiction treatment research is that clients’ substance use outcomes are significantly affected by who provides the treatment (Project MATCH Research Group, 1998). When therapist effects (differences in client outcomes from one therapist to another) are evaluated in studies delivering standardized treatment, they are usually present, and sometimes are larger than those between the different treatment methods being tested. Addiction counselors vary widely on many variables, including their therapeutic orientation, which in turn influences the treatment methods they choose to use (Moyers & Miller, 1993).
Our research about therapists began with studies comparing counselor-delivered behavioral treatment with “bibliotherapy,” namely giving clients a self-help guidebook and instructing them to go home, follow its advice, and pursue change on their own. In every one of our studies of this kind, we found no significant differences between therapists’ average outcomes and those for clients randomly assigned to bibliotherapy (Harris & Miller, 1990; Miller & Baca, 1983; Miller, Gribskov & Mortell, 1981, Miller & Taylor, 1980; Miller, Taylor & West, 1980; Schmidt & Miller, 1983). This could lead to the conclusion that therapists are no different from self-help, but that is not quite right. In one study (Miller, Taylor & West, 1980) we examined the specific success rates of nine individual therapists whom we had previously rated for the extent to which they showed accurate empathy (e.g., good reflective listening to clients) during their behavior therapy sessions. While the average success rate for therapists with randomly assigned cases was no different from the 60% positive outcome rate in the bibliotherapy group, there was wide variation among therapists’ caseloads, from 25% to 100% successful outcomes. Five of the nine therapists had success rates higher than bibliotherapy, one the same, and in three cases it looked as though the clients would have been better off going home with a good book than working with counselors. Furthermore, we found that we could accurately predict which therapists would have high or low success rates, based on their skillfulness in empathic listening to their clients (Miller, Taylor & West, 1980), a predictive relationship that still held up for two-year drinking outcomes (Miller & Baca, 1983). The better therapists were are listening to their clients, the more their clients changed.
Therapists also make a difference in how clients respond during treatment sessions, which in turn is related to client outcomes. In one study we were able to predict drinking outcomes over one year post-treatment from a single therapist response during treatment: the more the therapist confronted, the more the client drank (Miller, Benefield & Tonigan, 1993).
Project MATCH was a highly controlled multisite trial in which therapists closely followed treatment manuals to deliver standardized cognitive-behavior therapy, motivational enhancement therapy, or twelve-step facilitation therapy. Treatments were randomly monitored and closely supervised, with quality control measures that produced high adherence. Nevertheless in all three treatments, significant therapist effects remained after controlling for site and client characteristics (Project MATCH Research Group, 1998). Sometimes these effects went away by eliminating one or two outlier therapists with outstandingly poor outcomes, but in motivational enhancement therapy, the distribution of therapist effects was wider (DiClemente et al., 2003).
Publications on Therapist Effects in Addiction Treatment (in chronological order)
Miller, W. R., & Taylor, C. A. (1980). Relative effectiveness of bibliotherapy, individual and group self-control training in the treatment of problem drinkers. Addictive Behaviors, 5, 13-24.
Miller, W. R., Taylor, C. A., & West, J. C. (1980). Focused versus broad spectrum behavior therapy for problem drinkers. Journal of Consulting and Clinical Psychology, 48, 590-601.
Miller, W. R., Gribskov, C. J., & Mortell, R. L. (1981). Effectiveness of a self-control manual for problem drinkers with and without therapist contact. InternationalJournal of the Addictions, 16, 1247-1254.
Miller, W. R., & Baca, L. M. (1983). Two-year follow-up of bibliotherapy and therapist-directed controlled drinking training for problem drinkers. Behavior Therapy, 14, 441-448.
Schmidt, M. M., & Miller, W. R. (1983). Amount of therapist contact and outcome in a multidimensional depression treatment program. Acta Psychiatrica Scandinavica, 67, 319-332.
Harris, K. B., & Miller, W. R. (1990). Behavioral self-control training for problem drinkers: Components of efficacy. Psychology of Addictive Behaviors, 4, 82-90.
Miller, W. R., Benefield, R. G., & Tonigan, J. S. (1993). Enhancing motivation for change in problem drinking: A controlled comparison of two therapist styles. Journal of Consulting and Clinical Psychology, 61, 455-461.
Moyers, T. B., & Miller, W. R. (1993). Therapists’ conceptualizations of alcoholism: Measurement and implications for treatment. Psychology of Addictive Behaviors, 7, 238-245.
Project MATCH Research Group (1998). Therapist effects in three treatments for alcohol problems. Psychotherapy Research, 8, 455-474.
DiClemente, C. C., Carroll, K. M., Miller, W. R., Connors, G. J., & Donovan, D. M.(2003). The effects of therapist characteristics and the process of psychotherapy. In T. F. Babor & F. K. Del Boca (Eds.), Treatment matching in alcoholism (pp. 166-183). Cambridge, UK: Cambridge University Press.