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Thursday, December 31, 2009

Antidepressants and Risk of Stroke

The December issue of the Archives of Internal Medicine contains a paper based on the Women's Health Initiative dataset (a large cohort of community dwelling women aged 50-79 in the US) that describes a possible association between antidepressant use and stroke (link to abstract). Hemmorhagic stroke (strokes caused by bleeding in the brain) seemed to account for most of the association. The authors also looked for an association between antidepressant use and coronary heart disease - finding no association. This report may cause some alarm for people taking antidepressant medications, but it is important (in my view) to consider three factors when interpreting these results. First, depression itself is associated with cardiovascular disease, so studies such as this one are vulnerable to "confounding by indication" - a situation where the reason for use of a medication causes a problem that subsequently seems to be due to the medication itself. The study used sophisticated means to control for confounding by indication, but even the most sophisticated approaches are not always effective for controlling this type of bias. Second, this is not the first study to look at this possibility, and the literature as a whole has been inconsistent. On the other hand, some antidepressants are known to increase the risk of bleeding related complications, so what is being reported is biologically plausible. The risk-benefit trade-offs for antidepressant use need to be better delineated so that people can make informed decisions about depression treatment - this study is an example of one that is pursuing this goal. The risks and benefits may play out differently in people with severe depression and/or other risk factors for stroke - hopefully, research in this area will remain active until these issues are decisively resolved.

Friday, December 25, 2009

Depression and Employment Status

We've recently been looking at the impact of depression on employment status in Canadians using longitudinal data from the National Population Health Survey. We felt that this was important since, although it is well known that unemployment and depression are associated, it is possible both that unemployment could cause depression and that depression could cause unemployment. We were particularly interested in looking at the latter question. We selected people who were all working at baseline, divided these into groups that experienced (or did not) an episode of major depression. The effect of depression was greatest in young people - perhaps reflecting the greater difficulties faced by younger people in coping with depression, or their greater vulnerability to its effects (for example, because they may be less well-established in their career). However, it is also possible that older people who were working at baseline represented a subset of those who were more effective at coping with the symptoms - ie. those whose careers had been interrupted by depression prior to the baseline interview (1994) would not have been eligible, a selective effect that may have occurred less often in the younger respondents.

The results are published in the Canadian Journal of Psychiatry, here.