Mick Hartley

Some cheery news about depression. It's been regularly linked to all kinds of health downsides in the past, but according to this latest study it's not so much the biochemical changes associated with depression that do the damage, it's rather the depressives' behaviour, like smoking, not taking exercise, and slitting their wrists:

Whooley studied more than 1,000 patients with heart disease at the VA for nearly five years. The patients filled out regular questionnaires to determine their mood state, and were asked yearly to report on any heart-related events. Researchers took blood and urine samples to measure their levels of omega-3 fatty acids, cortisol and the inflammatory marker C-reactive protein, as well as the neurotransmitters serotonin and norepinephrine — all agents that may be involved in both depression and heart disease. In all, about 20% of the participants reported depressive symptoms; over five years, those patients had a 50% higher rate of additional heart problems, compared with their non-depressed peers.

Whooley's team studied the depressed group further. Researchers systematically adjusted for each potential risk factor to figure out whether it was mediating the link between depression and heart disease. Physiological factors, such as serotonin levels or CRP, for example, appeared not to have much impact. But when researchers adjusted for physical activity — that is, when they analyzed the data by assuming identical levels of exercise in both depressed and non-depressed patients — the difference in heart disease risk between the groups disappeared. Indeed, inactivity among the depressed patients gave them a 44% greater risk of having a heart event than people who were not depressed, accounting for nearly all of the depressed patients' 50% higher risk. Picking up the remainder of the increased risk was cigarette smoking.

The findings suggest that the effect of depression on heart health may have less to do with changes in hormones or other biochemical pathways, and more to do with behavior. Compared with other people, notes Whooley, the depressed are less healthy overall — they're less likely to exercise or take their heart medications, and are more likely to smoke. The relationship also feeds back on itself; previous studies show that exercise not only improves cardiovascular health, but also elevates mood and can ease depression.

It always seemed so unfair that sufferers from depression were burdened with these research findings about how, just by being depressed, they were slowly but surely killing themselves. As if life wasn't bad enough anyway, being depressed and all. Depressives can now take heart, as it were, from these findings. What goes around comes around: medical research takes away control of our lives, but then, occasionally, gives it back again. We should celebrate such moments.

Feeling down? Get on yer bike.