The shape of change in psychotherapy: longitudinal assessment of personal problems.

We propose 4 parameters that describe the course of change in the subjective intensity of personal problems during psychotherapy: (a) the problem's initial severity; (b) its rate of change (deterioration or improvement); (c) its instability (day-to-day variability in intensity); and (d) its curve (change in the rate of change during treatment). We constructed indexes of these parameters for 10 individualized personal problems rated 3 times per week by each of 40 clients (most were diagnosed as depressed) over the course of their 16-session treatment and associated assessment periods. Initial severity predicted problems' reported salience to clients. The rate of change parameter was correlated (across clients) with traditional pretreatment to posttreatment outcome measures. Instability was high, and problems dealing with tension symptoms and mood were more unstable than were problems dealing with relationships or self-esteem. Cutting across problem content were large individual differences among clients in the patterns of change.