The link between circadian rhythms and mental health is increasingly recognised, with disruptions to the body’s internal clock being associated with mood disorders such as depression, anxiety, and bipolar disorder. The synchronisation of sleep-wake cycles, hormone secretion, and neurotransmitter activity with circadian rhythms is essential for emotional well-being.
A study published in The Lancet Psychiatry examined the relationship between circadian disruption and mental health disorders in a large UK population cohort. The findings suggested that individuals with irregular sleep patterns, late-night social activities, and inconsistent exposure to natural light exhibited higher rates of depression and anxiety. The study highlighted that modern lifestyles, particularly those involving excessive screen time and shift work, contribute significantly to circadian misalignment.
Neurotransmitters such as serotonin and dopamine, which regulate mood and emotional stability, are influenced by circadian rhythms. Disruptions in light exposure and sleep patterns can alter the production of these chemicals, leading to mood disturbances. The regulation of the hypothalamic-pituitary-adrenal (HPA) axis, which controls stress responses, is also affected by circadian misalignment, exacerbating anxiety and depressive symptoms.
Therapeutic interventions such as light therapy, melatonin supplementation, and cognitive behavioural therapy for insomnia (CBT-I) have shown promise in improving mental health by restoring circadian balance. Encouraging consistent sleep patterns and reducing exposure to artificial light before bedtime can significantly improve emotional well-being and reduce the risk of mood disorders.
Social and occupational changes, such as flexible working hours and reduced screen exposure before sleep, can further support circadian alignment. Establishing a fixed bedtime and wake-up schedule, even on weekends, has been shown to improve both sleep quality and mental health outcomes. Additionally, studies suggest that outdoor physical activity, particularly in the morning, can reinforce natural circadian cues and mitigate symptoms of depression.
Public awareness campaigns about the impact of light exposure and screen use on mental health could play a key role in reducing circadian-related mood disorders. Schools and workplaces could implement policies that promote natural light exposure and regulate the use of artificial lighting to support circadian health.
Reference: Lyall, L. M., Wyse, C. A., Celis-Morales, C., Ward, J., & Smith, D. J. (2018). Association of disrupted circadian rhythmicity with mood disorders. The Lancet Psychiatry, 5(6), 507-514. https://doi.org/10.1016/S2215-0366(18)30139-1
