Ki. Howard et al., A PHASE MODEL OF PSYCHOTHERAPY OUTCOME - CAUSAL MEDIATION OF CHANGE, Journal of consulting and clinical psychology, 61(4), 1993, pp. 678-685
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.