Circadian Rhythm Key to Atypical Depression Mystery, Study Finds

About 21% of patients with depression have an atypical form that is less likely to respond to common antidepressants, an Australian study suggests. New research, published in Biological Psychiatry, suggests a genetic link between circadian rhythm and atypical depression, which the researchers said was related to traits such as weight gain and hypersomnia, and mainly affected women. “What Australian doctors have been taught mostly is the notion of one exogenous, environmental type of depression versus one biological type of depression,” said co-author Professor Ian Hickie, the co-director of the University of Sydney’s Brain and Mind Centre. “But here there’s a different biology completely.