Daily smoking, low mastery associated with repeat episodes of depression in people with a history of depression

Depression is a common disorder that negatively affects quality of life for people with the condition. About 65% of people with depression have repeat episodes. Depression can be associated with weight and dietary control, pain and inattention to other health issues.

To identify risk factors associated with a long-term prognosis of depression, researchers looked at 585 adults from Statistics Canada's National Population Health Survey who had suffered depression in 2000/01. Of the patients, 65% were women, the average age was 38.5 years, and 82% were in the middle- to high-income bracket. More than half the patients had one or more episodes of depression in the following six years. Being an immigrant appeared to have protective status against relapse in people with severe depression.

The researchers found that age, sex and income were not associated with future depressive episodes but that daily smoking and low mastery were associated with long-term depression. Mastery is the sense that people have control over their lives and their circumstances. In this study, high levels of mastery appeared to be protective against further depression.

"History of depression is a well-known clinical indicator of future depressive episodes; however, smoking and mastery are more novel prognostic factors that are not well accounted for in current clinical practice," states Dr. Ian Colman, Department of Epidemiology and Community Medicine, University of Ottawa, with coauthors.

"Future research should evaluate the benefits of including smoking cessation and mastery in existing clinical guidelines for the treatment of depression," they conclude.