NEW YORK (Reuters Health) - For people who have recovered from a bout of clinical depression, mild emotional stress or sadness can reactivate depressive thinking and this may increase the risk of relapse, researchers report.
Remission from depression can be "a period of marked sensitivity to emotional stress as well as an increased risk of relapse," Dr. Zindel V. Segal, of the University of Toronto, Ontario, Canada, and colleagues write in the Archives of General Psychiatry.
The researchers examined if mood-linked changes in thinking predicted relapse in 301 adults recovering from a major depressive disorder.
In the first phase of the study, the patients were treated with antidepressant medication or cognitive behavior therapy. In phase 2, regular clinical assessments were conducted for 18 months in the 99 patients who achieved clinical remission.
During the second phase, the subjects underwent sad mood provocation. They were asked to recall a time in their lives when they felt sad, and at the same time the researchers had them listen to the orchestral introduction to "Russia Under the Mongolian Yoke" by Prokofiev, played at slow speed. Previous studies have found this to bring on an unhappy mood.
Compared with patients who underwent cognitive behavior therapy, those who received antidepressant medication showed a greater tendency to have depressive thoughts after mood provocation. The magnitude of the mood-linked response predicted relapse during the 18 months, regardless of the type of previous treatment.
These findings suggest that "even a mild negative mood, when experienced by someone with a history of depression, can re-instate some of the cognitive features observed in depression itself," Segal's team concludes.