Researchers have found out why common antidepressants fail to help a significant share of patients with severe depression, the website infohub.kz reports.
Specialists from the University of Sydney analyzed clinical and genetic data from more than 10,000 participants in a large-scale Australian study. They found that nearly a quarter of patients have a condition linked to disruptions in the circadian system — the body's internal 24-hour biological clock that governs the sleep-wake cycle. The new subtype of the disorder has been named circadian depression.
Patients with this form of the disorder often report seasonal flare-ups, a habit of going to bed late, long sleep during episodes and a persistent feeling of exhaustion in the mornings. In addition, the illness begins at a younger age in these patients, runs a more severe course and is accompanied by an increased genetic predisposition to inflammatory processes, cardiovascular disease and attention deficit hyperactivity disorder.
Standard first-line antidepressants that affect serotonin and noradrenaline levels are largely ineffective in circadian depression and more often cause side effects. The authors stress that such people need different treatment approaches. Doctors propose using bright light therapy, melatonin and drugs that regulate biological rhythms from the outset to relieve patients' symptoms faster.