Problems with sleep and internal body clock can trigger or exacerbate a range of psychiatric disorders, a new study shows.
Sleep disturbances such as insomnia have long been linked to psychiatric disorders, but in a recent research review, an international team of scientists found that disturbances in the circadian rhythm are common in every category of psychiatric disorder.
The research is published on 23 February in the Proceedings of the National Academy (PNAS) and suggests that a greater understanding of sleep and its connection to mental health could uncover new holistic ways to treat psychiatric disorders.
Researchers from the Universities of Southampton, Bristol, King’s College London, Stanford University, and other institutions undertook a review of research focusing on how sleep and circadian factors affect people with psychiatric disorders.
Focusing on adolescents and young adults, the researchers examined the possible mechanisms behind sleep-circadian disturbances in psychiatric disorders. Adolescence is a time when people are most at risk of developing mental health disorders. In addition, physiological changes in sleep combine with behavioural changes, such as staying up later, getting less sleep and sleeping in at the weekends, which disrupt sleep and circadian rhythms.
The review showed that insomnia is more common in people with mental health disorders than in the general population. Around a third of people with mood disorders were found to experience both insomnia and hypersomnia, a condition where patients find it hard to sleep at night but feel drowsy in the daytime. Over half of patients with psychosis were found to suffer from insomnia, especially in the early stages of the illness.
Fewer studies examined circadian rhythm sleep-wake disorders (CRSWD), but of the ones that did, the researchers found that 32 per cent of patients with bipolar disorder go to sleep and wake later than usual. Body clock processes in people with bipolar disorder have been reported to run seven hours ahead during manic episodes and four to five hours behind during the depressive phase.
Professor Matt Jones from the University of Bristol said: ‘Many current treatments for psychiatric disorders are based on one-size-fits-all, trial-and-error approaches. Understanding the sleep and circadian patterns of individuals living with these disorders offers exciting opportunities for early intervention and the precisely tailored therapies people deserve.’
He added: ‘New, wearable devices able to accurately measure these sleep and circadian patterns across long timescales should really help bring this precision to psychiatry.’
The researchers examined several other factors which could impact sleep and subsequent mental health issues, including the role of genes, exposure to light and neuroplasticity. Time outdoors was associated with a lower probability of mood disorder, and people who are genetically predisposed to lower activity levels are at a higher risk of experiencing depression, mood instability, and neuroticism.
From the review findings, the researchers suggest that the timing of medication, meals and exercise could impact circadian phases.
Dr Renske Lok, from Stanford University, who co-led the review, explained: ‘Targeting sleep and circadian risk factors presents the opportunity to develop new preventative measures and therapies. Some of these are population-level considerations, such as the timing of school and work days or changes in the built environment to optimise light exposure. Others are personalised interventions tailored to individual circadian parameters.’
As research into mental health takes advantage of the advances in sleep and circadian science, the researchers hope the findings translate improved understanding and treatment of psychiatric disorders.
‘The sleep-circadian interface: a window into mental disorders’ by Nicholas Meyer, Sarah L. Chellappa et al. published in Proceedings of the National Academy (PNAS)
