Biological clock rhythm affects response to depression drugs

A biological clock out of sync with daily life may help explain why standard antidepressants work less well for some people, ERR reports, citing a new study.

Researchers in Australia analysed genetic and health data from more than 11,000 people. They found that nearly one in four people with depression had a form directly linked to disruptions in their circadian rhythm.

People with this form of depression tended to develop the condition at a younger age and experience more severe illness. They were also more likely, due to genetic predisposition, to have attention-deficit/hyperactivity disorder, a high body mass index and insulin resistance.

Standard antidepressants were less effective for these patients, who also reported more side effects, including weight gain, nausea and drowsiness. The researchers said a shift in biological rhythms may trigger the illness, while standard antidepressants do not regulate the body clock or sleep cycles.

Because their biological clocks and social schedules are out of sync, these patients may benefit from approaches that directly regulate sleep and wake cycles, such as timed light therapy or melatonin. The findings were published in The British Journal of Psychiatry.