A phase model of psychotherapy outcome: Causal mediation of change.

TLDR

The study proposes a 3‑phase model of psychotherapy outcome that sequentially improves well‑being, reduces symptoms, and enhances life functioning. The model predicts that progression to later phases depends on earlier gains, with well‑being improvement driving symptom reduction and symptom reduction driving life‑functioning improvement, and this was tested using self‑report data from 17‑session psychotherapy patients. Empirical analysis confirmed the 3‑phase sequence, showing that well‑being gains precede and are necessary for symptom reduction, which in turn precedes and is necessary for life‑functioning improvement.

Abstract

A 3-phase model of psychotherapy outcome is proposed that entails progressive improvement of subjectively experienced well-being, reduction in symptomatology, and enhancement of life functioning. The model also predicts that movement into a later phase of treatment depends on whether progress has been made in an earlier phase. Thus, clinical improvement in subjective well-being potentiates symptomatic improvement, and clinical reduction in symptomatic distress potentiates life-functioning improvement. A large sample of psychotherapy patients provided self-reports of subjective well-being, symptomatic distress, and life functioning before beginning individual psychotherapy and after Sessions 2, 4, and 17 when possible. Changes in well-being, symptomatic distress, and life functioning means over this period were consistent with the 3-phase model. Measures of patient status on these 3 variables were converted into dichotomous improvement-nonimprovement scores between intake and each of Sessions 2, 4, and 17. An analysis of 2 x 2 cross-classification tables generated from these dichotomous measures suggested that improvement in well-being precedes and is a probabilistically necessary condition for reduction in symptomatic distress and that symptomatic improvement precedes and is a probabilistically necessary condition for improvement in life functioning.