Key facts
- Circadian depression affects 23% of participants in a study of 11,380 Australians.
- Symptoms include seasonal illness patterns, delayed sleep timing, longer sleep duration when depressed, being a night owl, waking feeling tired, and social jetlag.
- This subtype is associated with younger age of onset, more depressive episodes, higher suicidality, and hypomanic/psychotic-like symptoms.
- Genetic links to ADHD and mood disorders, as well as metabolic and inflammatory markers, were found in individuals with circadian depression.
- Standard antidepressant drugs like SSRIs and SNRIs were less effective for this subtype.
Australian researchers have identified a new subtype of depression, named "circadian depression," which is linked to disruptions in the body's internal clock and affects nearly a quarter of individuals with severe and recurrent depression. The study, published in the British Journal of Psychiatry, analyzed data from 11,380 Australians. Individuals with this subtype exhibit more severe symptoms, including a younger age of onset, increased episodes, higher suicidality, and a poorer response to traditional antidepressant treatments like SSRIs and SNRIs. Researchers suggest that treatments targeting circadian rhythms, such as melatonin and light therapy, may be more beneficial.