Exploring therapist effectiveness across multiple domains over time.

Despite the common assumption that increased therapist experience correlates with improved client outcomes, studies reveal inconsistent relationships between therapist experience and therapy effectiveness. Some studies have demonstrated a slight worsening of client outcomes as therapists gain more experience. Yet, there are few studies that have examined how therapists change in their client outcomes over time, especially across different outcomes (e.g., depression, life functioning, anxiety). The present study used the Behavioral Health Measure-17 to investigate therapist effectiveness over time on multiple treatment outcomes (e.g., general distress, life functioning, anxiety, alcohol/drug use) using a large naturalistic sample of 613 professional therapists and 42,690 clients over approximately 12 years of psychotherapy data. Our results show a significant decrease in client outcomes over time in three domains: general distress, life functioning, and anxiety, albeit small-sized effects. Our findings also indicate that therapist caseload and baseline severity were not associated with predicting client outcomes and that, unexpectedly, the severity of therapist caseloads decreased over time. These findings underscore the importance of a nuanced understanding of therapist effectiveness, challenging the assumption of universal improvement with experience. Furthermore, we believe that these findings may offer preliminary support for matching therapists with clients based on domain-specific strengths. (PsycInfo Database Record (c) 2024 APA, all rights reserved).