Predicting a rapid response during psychotherapy for depression

Rationale. According to ‘sudden gains’ and ‘rapid response’ methods, considerable numbers of patients experience large robust reductions in depression in early sessions across a range of psychotherapeutic modalities. Yet, surprisingly few researchers have investigated the processes that might help explain this phenomenon. Aims. Accordingly, the aims of this thesis were threefold: 1) To replicate previous findings of a rapid response to psychotherapy, 2) To investigate the role of empirically supported pre-existing interpersonal patient factors, 3) To examine systematically the therapeutic processes that characterise both rapid and gradual response profiles. Methods. Sixty-two adults received 16 weekly sessions of supportive-expressive dynamic psychotherapy (Luborsky et al., 1995). A rapid response was defined as a reduction of at least 50% of patients’ intake Beck Depression Inventory score by Week 6. Following a comparison between rapid and gradually responding patients’ attachment and interpersonal patterns, 20 (10 rapid-, 10 gradual-responders’) early therapy sessions (session 3) were rated with the Psychotherapy Process Q-Set (PQS; Jones, 2000). The PQS is a pan-theoretical method of systematically characterising therapist-patient interactions that provides a meaningful index of process that can be used in comparative analyses. Results. Over one third of patients (23/62) experienced a rapid response, by Session 6. This accounted for an average 96% of their entire symptom reductions. Rapid responders were more than twice as likely to recover by Session 16, and were significantly less depressed at 52 week follow-up, after adjusting for intake symptom levels. Rapid responders also presented with fewer interpersonal problems. On the other hand, pre-therapy characteristics of gradually responding patients included having lower interpersonal mastery, a more domineering interpersonal style, and greater social isolation and attachment fears concerning intimacy. The interpersonal differences between rapid and gradually responding patients were reflected in differences in psychotherapy processes. Despite equivalent ratings of observer-rated working alliance, results from the PQS suggested that as early as Session 3, rapid responders were at a more advanced stage of therapy, characterized by a willingness to work on strong emotions such as guilt. In contrast, gradual responders’ sessions were dominated by externalising, hostility, and defensiveness. Conclusion. Pre-existing interpersonal patient factors determine the speed of recovery in psychotherapy through their differential effects on therapeutic process.