Australian Study Identifies Circadian Depression in 23% of 11,380 Patients

3 articles · Updated · The Guardian · Oct 20

Nearly 1 in 4 participants in an Australian study met criteria for a newly defined “circadian depression” subtype tied to disrupted body-clock rhythms and distinct from other forms of depression.
11,380 Australians with mostly severe, recurrent depression were analyzed using clinical and genetic data; the subtype was linked to younger onset, more episodes, greater suicidality, and more hypomanic and psychotic-like symptoms.
SSRIs and SNRIs were less effective and caused more side effects in this group, researchers said, pointing instead to chronobiological approaches such as melatonin, morning light exposure, regular sleep-wake cycles and meal timing.
Genetic risk for ADHD and mood disorders, along with metabolic and inflammatory markers, suggested an underlying biology rather than simply poor sleep.
The study, published in the British Journal of Psychiatry, was limited to participants of genetically inferred European ancestry, and outside experts said the findings are promising but still need replication and clearer subtype criteria.