A team at the University of Sydney has discovered a distinct form of depression, termed “circadian depression,” which is closely tied to the body’s natural 24-hour cycle. This variant accounts for nearly a quarter of diagnoses in their study looking at people with severe, recurrent or persistent depression.
By analyzing clinical and genetic information from over 10,000 Australians, researchers pinpointed this new category. Circadian depression is marked by reduced effectiveness of standard serotonin-based antidepressants but shows improved response to therapies, both behavioral and medical, that address the brain’s circadian rhythm circuits.
Symptoms and Associated Risks
Those with circadian depression often exhibit patterns such as seasonal mood fluctuations, prolonged sleep during depressive episodes, persistent fatigue upon waking, and a tendency toward night-time activity. This subtype also tends to manifest earlier in life, accompanied by more intense symptoms, including manic episodes and heightened suicidal ideation.
Furthermore, individuals with this condition face raised genetic risks for inflammatory and cardiovascular issues, as well as significant neurodevelopmental disorders like ADHD. The findings, published in the British Journal of Psychiatry, deepen the understanding of the genetic factors driving circadian depression.
Read Also: Whey Protein Before Meals May Lower Blood Sugar Spikes
Conventional antidepressants, such as SSRIs and SNRIs, are typically the initial treatment choice for depression but are less effective and more likely to cause side effects in those with circadian depression. Alternatively, treatments that target the circadian rhythm, including light therapy and melatonin, may offer better outcomes for this group.
Dr. Jacob Crouse, a lead researcher, suggests that circadian rhythm-focused treatments like light therapy and melatonin should be prioritized earlier in the treatment process for those with this condition. Dr. Emiliana Tonini, the study’s primary author, highlights that depression is not a one-size-fits-all condition, and recognizing the unique traits of subtypes like circadian depression can lead to more timely and effective treatment options.
Professor Ian Hickie, Co-Director of the Brain and Mind Centre, stresses the importance of identifying circadian depression in younger individuals to prevent early treatment setbacks and minimize side effects. He notes that while SSRIs are often the first prescribed treatment for young people, a significant portion may benefit more from circadian-focused medical and behavioral interventions.