Abstract

Despite successful treatment for recurrent depression, patients often evidence fluctuations in residual symptoms over time during recovery. Prior research has shown such variability to be predictive of later recurrence for those with extensive histories of previous episodes. A life stress approach was used to examine: (1) the relationship between depression symptom variability and concurrent life stress, and (2) how the presence or absence of life stress informs the association between depression symptom variability and subsequent recurrence. Over a follow-up period of up to three years in a group of recurrent but recovered patients, the following were examined: (1) the association between indices of symptom variability and the rates of both independent and dependent stressful life events; (2) the difference in the frequency of event-related and non event-related increases in depression symptoms; and (3) the prediction of recurrence by the frequency of event-related and non event-related increases. Patients were part of a randomized treatment protocol designed to evaluate the effects of medication and psychotherapy on recurrence of depression. Independent events were associated with symptom increases for medicated but not for unmedicated participants. Interestingly, while the two groups did not differ in the frequency of event-related increases, unmedicated patients had more increases in symptoms that were not related to life events. The frequency of both event- and non event-related symptom increases independently and positively contributed to the prediction of recurrence, even after controlling for maintenance medication. These findings suggest that for individuals with a history of recurrent depression, medication may buffer individuals from variability that is unrelated to life events but not from event-related variability, though both types of variability predict recurrence regardless of medication status.

These results are discussed in relation to major different theoretical models depicting the role of life stress in the recurrence of depression. This study suggests that some types of variability in depression symptoms unrelated to life events may be linked to disordered psychobiological processes responsive to medication, while other types of variability reflect reactions to adversity unaffected by medication, which may or may not be disordered. Nonetheless, both types of variability are predictive of recurrence.