# The link between circadian rhythm and mental health - URL: https://alisanburak.com/en/sirkadiyen-ritim-ve-ruh-sagligi-bagi - Language: en - Last updated: 2026-08-15 - Page title: The link between circadian rhythm and mental health | Assoc. Prof. Dr. Alişan Burak Yaşar > You think you’re getting the same 7 hours of sleep. Your brain pays attention to WHICH 7 hours — and so does your mood. In a UK Biobank analysis of 91,105 This page was translated automatically from Turkish. [Read the original](https://alisanburak.com/sirkadiyen-ritim-ve-ruh-sagligi-bagi) [← Back to blog](https://alisanburak.com/en/blog) # The link between circadian rhythm and mental health May 11, 2026Recent Articles You think you’re getting the same 7 hours of sleep. Your brain pays attention to WHICH 7 hours — and so does your mood. In a UK Biobank analysis of 91,105 people, those with lower circadian rhythm amplitude had a 6% higher lifetime risk of major depression and an 11% higher risk of bipolar disorder. Mood instability, loneliness, and neuroticism accompany this pattern (Lyall et al., Lancet Psychiatry, 2018). The mechanism depends on darkness. Melatonin is synthesized in the pineal gland; light suppresses it, and darkness increases it. The duration of production equals the LENGTH OF THE NIGHT (Cipolla-Neto, Endocrine Reviews, 2018). Cortisol, meanwhile, peaks in the morning and reaches its lowest level at night — in depression, this curve flattens and nighttime levels rise (Knezevic, Cells, 2023). The glymphatic system, which clears waste from the brain, works only during sleep; amyloid-β clearance increases approximately twofold compared with wakefulness (Rasmussen, Lancet Neurology, 2018; Hauglund, Cell, 2024). Memory consolidation is actually “carried out” during slow-wave sleep (Tononi & Cirelli, Neuron, 2014). The key point: in >40,000 days of wearable device data, circadian phase disruption precedes mood symptoms. This occurs in 66.7% of cases of MDD and 85.7% of cases of bipolar I disorder (Song et al., eBioMedicine, 2024). Response to SSRIs is also lower in people with an evening chronotype (Crouse, Biol Psychiatry, 2024). It’s not about the clock, but ALIGNMENT WITH DARKNESS. In adults, the biological night averages 9–11 hours; melatonin onset occurs around 21:00–23:00. “23:00–05:00” is not a rigid rule, but the core period of the biological night for most adults. It shifts to 22:00–04:00 in early chronotypes and 00:00–06:00 in late chronotypes. 5 steps: (1) Get 15–30 minutes of bright light in the morning. (2) Use dim, warm light starting 2 hours before bed. (3) Keep a consistent wake-up time (weekday/weekend difference ≤30 minutes). (4) Exercise early in the day, finishing at least 3 hours before bed. (5) Keep the bedroom completely dark, at 18–20°C, quiet, and screen-free. Chronotherapy does not replace treatment; specialist assessment takes priority in clinical depression, bipolar disorder, OSA, or chronic insomnia. [Click here for scientific sources](https://alisanburak.com/wp-content/uploads/2026/05/Sirkadiyen_Ritim_Ruh_Sagligi.pdf) [← Previous Does your mind become more active at night?](https://alisanburak.com/en/geceleri-zihniniz-aciliyor-mu)[Next → How Many Hours Should You Sleep, and When?](https://alisanburak.com/en/kac-saat-uyumali-ne-zaman-uyumali) --- Kaynak / Source: https://alisanburak.com/en/sirkadiyen-ritim-ve-ruh-sagligi-bagi İletişim / Contact: Bağdat Caddesi, Veli Güneysu Apt. No:453 K:4 D:9, Suadiye / Kadıköy, İstanbul · +90 532 642 95 25 · info@alisanburak.com · https://alisanburak.com/bagdat-caddesi-psikoterapi-iletisim