A PHASE MODEL OF PSYCHOTHERAPY OUTCOME - CAUSAL MEDIATION OF CHANGE

A 3-phase model of psychotherapy outcome is proposed that entails prog ressive 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 whe ther progress has been made in an earlier phase. Thus, clinical improv ement in subjective well-being potentiates symptomatic improvement, an d clinical reduction in symptomatic distress potentiates life-function ing improvement. A large sample of psychotherapy patients provided sel f-reports of subjective well-being, symptomatic distress, and life fun ctioning before beginning individual psychotherapy and after Sessions 2, 4, and 17 when possible. Changes in well-being, symptomatic distres s, and life functioning means over this period were consistent with th e 3-phase model. Measures of patient status on these 3 variables were converted into dichotomous improvement-nonimprovement scores between i ntake and each of Sessions 2, 4, and 17. An analysis of 2 x 2 cross-cl assification tables generated from these dichotomous measures suggeste d that improvement in well-being precedes and is a probabilistically n ecessary condition for reduction in symptomatic distress and that symp tomatic improvement precedes and is a probabilistically necessary cond ition for improvement in life functioning.