Rhythm of the night: sleep and mental health

This weekend it’s time to put the clocks forward. While we’ll all welcome the start of Spring and the promise of lighter evenings, some of us might not be so excited about our alarm going off an hour earlier that we’re used to. Within a few days most of us will adjust to the hour of lost sleep, but for some people with mental health conditions, problems with sleep can be a year-round issue.

The relationship between mental health and sleep is complex. Sleep disturbance is a well-known symptom of many mental health conditions such as anxiety, depression, bipolar disorder and schizophrenia. However, people with disrupted sleep due to insomnia or shift work are at increased risk of developing problems such as depression. This suggests that sleep disturbance could be both a cause and a result of mental health conditions.

So how exactly does sleep disruption influence our mental health? The answer may lie in its effect on our circadian rhythms. These are biological processes in the body that have approximately 24-hour cycles (hence the name, which comes from the Latin “circa diem”, meaning “about a day”).

Circadian rhythms are controlled by a “master clock”, located in an area of the brain impressively named the suprachiasmatic nucleus, which estimates the time of day based on the level of light detected by our eyes. We also have “peripheral” clocks located throughout various organs in our body (e.g. the liver), which are coordinated by the master clock.

Our body’s system of clocks works like an orchestra; the peripheral body clocks act like the different sections of the orchestra (i.e. brass, strings, woodwind, percussion), and are ‘conducted’ by the master body clock. Working together they produce the music that is our circadian rhythms, which influence our behaviours, affecting when we feel sleepy, hungry or alert.

Playing out of time

However, when our behaviour or environment is at odds with our circadian rhythms, for example when we are awake or exposed to light when our body thinks we should be asleep, this disrupts both the master and peripheral clocks, and the orchestra begins to play out of sync with the conductor.

This can affect numerous physiological processes in the body that have circadian rhythms, but can also affect processes in the brain involved in mental health, leading to symptoms of mental illness. In turn, these symptoms can make it more difficult for us to sleep, leading to a vicious cycle in which poor sleep act as both a trigger and a symptom.

Understanding the relationship between sleep and mental health has important implications for treatment and management of mental health conditions.

For example, some evidence suggests that maintaining regular sleep patterns reduces the chance of relapsing in bipolar disorder, and treating sleep problems such as insomnia can help with the symptoms of other conditions.

The latest research, although still in its infancy, also suggests that differences in the genetics that regulate our body clocks may make some people more susceptible to the negative effects of sleep loss. This information may eventually help us to prevent the development of mental health conditions by ensuring that these individuals maintain healthy sleep habits.

Surprisingly, even though we spend up to a third of our lives asleep, there’s still a great deal for researchers to learn about how it affects our bodies and minds. However, acknowledging its importance could be essential to improving our mental health.


Help with our bipolar and sleep research

We are exploring the relationship between sleep and mood in people with bipolar disorder. Visit our noticeboard to find out more and volunteer to help.

Katie Lewis

Katie Lewis is researching bipolar disorder and sleep at the MRC Centre for Neuropsychiatric Genetics and Genomics at Cardiff University.

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