Friday, July 24th at 1:00 pm
B35, Solomon Labs
Title: Predictors of Response to Medication and Cognitive Therapy in the
Treatment of Moderate to Severe Depression.
Despite abundant empirical evidence demonstrating that cognitive therapy
and antidepressant medications are effective treatments for depression,
neither treatment appears to work equally well for all patients. In the
three studies contained in this dissertation, I examined data from a
recent clinical trial comparing cognitive therapy and antidepressant
medications in order to identify variables associated with response to
these two treatments.
In the first study, I examined the differential effects of personality
pathology on short-term response and longer-term sustained response in
the two treatments. Patients without personality disorders responded
better to cognitive therapy then to medication treatment, whereas the
reverse was true for patients with a comorbid personality disorder. The
positive response to medications among patients with personality
disorders was sustained only when those patients were continued on
medications during the 12 month follow-up. Patients with personality
disorders who were withdrawn from medications evidenced an extremely low
sustained response rate.
In the second study, I investigated whether a comprehensive set of
baseline patient characteristics was associated with treatment response.
Findings indicated that chronic depression, older age, and lower
intelligence each predicted relatively poor response irrespective of the
treatment that was received. In addition, three prescriptive predictors
of treatment response were identified. Patients who were married,
unemployed, or experiencing a relatively large number of life events
evidenced superior response to cognitive therapy relative to medications.
In the third study, I examined four subsets of depressive symptoms and
found no evidence that the severity of these symptoms at intake
predicted differential response to the two treatments. In addition, I
examined change in the magnitude of these symptom sets over the course
of treatment and found that cognitive therapy produced greater change in
the atypical-vegetative symptoms of depression (hypersomnia and
hyperphagia) relative to medication treatment.
Several prognostic and prescriptive predictors of treatment outcome were
identified in this work. These findings, if replicated, would have clear
clinical utility for the appropriate matching of treatments to patients.
In addition, the pattern of findings should also help to refine theories
that seek to explain the mechanisms through which these two treatments
generate their therapeutic effects.