Study describes circadian depression subtype in about one-quarter of participants

Classification through six sleep and seasonal features

Researchers led by Jacob Crouse and Ian Hickie analyzed data from 11,380 participants and defined a proposed circadian subtype using six features, including seasonal symptom changes, delayed sleep timing, social jet lag, an evening chronotype, longer sleep when possible, and morning tiredness. The report says about one in four participants fit the subtype.

The reported analysis does not provide a directly comparable before-and-after measure of this proposed subtype's prevalence or treatment outcomes.

The researchers proposed a six-criterion circadian subtype of depression and reported that about one-quarter of the study participants met those criteria.

The report links the proposed subtype with earlier onset of depression, more severe reported clinical features, and lower reported effectiveness and more side effects from common antidepressants. The researchers suggested that treatments aimed at circadian rhythm, such as light therapy and melatonin, may be more relevant for some people, while stressing that treatment decisions should be individualized with a clinician.