Objective: Psychotherapy researchers have long questioned whether increased therapist experience is linked to improved outcomes. Despite numerous cross-sectional studies examining this question, no large-scale longitudinal study has assessed within-therapist changes in outcomes over time.
Method: The present study examined changes in psychotherapists' outcomes over time using a large, longitudinal, naturalistic psychotherapy data set. The sample included 6,591 patients seen in individual psychotherapy by 170 therapists who had on average 4.73 years of data in the data set (range = 0.44 to 17.93 years). Patient-level outcomes were examined using the Outcome Questionnaire-45 and a standardized metric of change (prepost d). Two-level multilevel models (patients nested within therapist) were used to examine the relationship between therapist experience and patient prepost d and early termination. Experience was examined both as chronological time and cumulative patients seen.
Results: Therapists achieved outcomes comparable with benchmarks from clinical trials. However, a very small but statistically significant change in outcome was detected indicating that on the whole, therapists' patient prepost d tended to diminish as experience (time or cases) increases. This small reduction remained when controlling for several patient-level, caseload-level, and therapist-level characteristics, as well as when excluding several types of outliers. Further, therapists were shown to vary significantly across time, with some therapists showing improvement despite the overall tendency for outcomes to decline. In contrast, therapists showed lower rates of early termination as experience increased.
Conclusions: Implications of these findings for the development of expertise in psychotherapy are explored. (PsycINFO Database Record
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