How sleep can be a powerful medicine for the mind

We all know lack of sleep is bad for us physically. But in the final part of this compelling series, we reveal the profound effects it can have on mental wellbeing, too...

Most of us would recognise that a lack of sleep on one day can affect our mood the next, making us grumpy, irritable, quick to lose our tempers and impulsive.

But a chronic lack of sleep can have a less well-acknowledged — and perhaps even more significant — impact on our mental health.

sleep is when problems are solved and our memories are consolidated (‘imprinted’ on our brains). A lack of sleep will influence what we remember, and tired brains tend to remember our negative experiences, forgetting the positive ones. As I’ve explained before, this selective memory can lead to depression.

Indeed, insomnia is recognised as one of the most common features of mental illness, across depressive illnesses and psychosis, such as bipolar disorder and schizophrenia.

A deterioration in sleep can even be used as a predictor of mental health problems.

Until recently this link between a lack of sleep and mental illness was thought to arise largely as a sideeffect of medication. this does not seem to be the whole story, as several studies have shown that people with mental illness can experience insomnia even when not taking medication such as anti-depressants or anti-psychotics.

so what is happening? It looks like there is an overlap between brain networks that govern our mental health and the brain circuits that generate sleep. As a result, any change in a brain circuit that causes mental illness will also affect sleep.

Poor sleep will destabilise brain function further and act to make the mental illness worse. And, of course, the symptoms of the mental illness will affect sleep. But if a lack of sleep is harmful to mental health, can improving sleep reduce the severity of mental illness?

this is an idea my team and I at oxford decided to test, using cognitive behavioural therapy for insomnia (or CBti), which, as I described in Wednesday’s Mail, is designed to change bad sleep habits and to encourage people to adopt behaviours that are proven to promote sleep — to treat insomnia without sleeping pills.

CBti is available through a sleep clinic, or you can also do it yourself by using app-based digital CBti, such as sleepstation or sleepio.

our CBti trial involved 3,755 people with insomnia as well as hallucinations and paranoia (a condition characterised by delusions of persecution, unwarranted jealousy or exaggerated self-importance).

A control group received no treatment for their insomnia; the rest received digital CBti through an app on their smartphones.

Compared with the control group, those on digital CBti experienced a significant reduction in insomnia — and a highly significant reduction in paranoia and hallucinations.

these exciting findings show that treatments for insomnia represent a new and powerful approach to reducing symptoms of mental illness.

IMPROVING OLDER PEOPLE’S MOOD

CBti approaches have been shown to help improve sleep and, as a result, help people lead healthier and happier lives. this is particularly true for older people, for whom CBti, and light therapy, have improved sleep and health.

In many nursing homes, light can be low, less than 200 lux in day areas and as little at 30 lux in tV rooms — this compares with between 10,000 to more than 60,000 lux outside, depending on the weather. Residents often see very little natural light.

sleep problems are notoriously common among care home residents. A Dutch study published in 2008 increased light in communal areas to about 2,000 lux and made bedrooms as dark as possible. the residents’ sleep and wake patterns became more normal. they were waking less in the night, and had fewer daytime naps.

significantly, improved sleep led to an increase in memory recall, problem solving, and feelings of wellbeing.

Using light intensity to help nursing home residents could be a cheap but effective alternative to drug treatments to calm night wanderers — and improve quality of life for patients.

EMPLOYERS MUST PRIORITISE SLEEP

oUR understanding of sleep has grown greatly over the past ten years, and so has our awareness of the consequences of insomnia.

All this week I’ve looked at how,

as individuals, we can take action to improve our sleep. But employers can — and should — also take simple measures in the workplace to address problems arising from insomnia and nightshift work — for their benefit and that of their staff.

Employers and employees have to accept that there will always be significant health consequences associated with sleep loss, and

that currently the best we can achieve is a reduction in the severity of symptoms associated with insomnia.

These are some of the changes that employers can make:

‘DROWSY DRIVER’ ALERTS: Nightshift work and long working hours can reduce your ability to concentrate and lead to micro- sleeps (uncontrollably falling asleep). This can be dangerous both in the workplace and on the drive home, and it is worth emphasising that the tired brain is so impaired that it cannot detect how tired it is.

Driver insomnia has long been recognised as a major cause of road accidents. A recent UK study, for example, showed that 57 per cent of junior doctors had either had a vehicle crash or near-miss after working the night shift.

For many years, the rail industry has used some form of ‘dead man’s handle’, or driver safety device, built into locomotives to alert train drivers if they have lost vigilance or fallen asleep.

Such preventative measures have not been widely adopted in private cars or commercial vehicles — until recently.

A range of devices is now available, including steeringpattern monitoring, vehicleposition-in-lane monitoring, and driver eye/ face monitoring to detect drowsiness.

Some motor manufacturers have recently incorporated this technology into newer models.

My own car is 14 years old and ready to be replaced, and the

availability of such technology will influence the type of car that I will choose to buy next. It would be sensible and appropriate for employers to provide, or subsidise, such devices for staff.

BRIGHTER LIGHTS: Increased tiredness and loss of vigilance during the night shift have been linked to an increased toll of accidents at work.

Keeping the office or factory sufficiently bright can improve alertness. To achieve peak alertness, a room should be lit with 1,000 lux or more.

BETTER FOOD: Vending machines and canteens invariably supply sugary, fatty foods — just the kind of treats we seek when we’re tired, but which produce a sugar rush, followed by a crash and increased tiredness.

So don’t have a blow-out before you start work. Ideally your canteen should help you by providing snacks and easy-todigest foods, with lots of protein (to avoid sugar spikes).

Soups, nuts and seeds, boiled eggs, chicken and tuna are ideal. (I would love to see The Great British Bake Off have an episode dedicated to delicious recipes for night-shift workers!).

THE RIGHT SLEEP TYPE FOR THE

JOB: Our individual sleep needs are partly determined by our genes. Some people are ‘larks’ (get up and go to bed early, 14 per cent of the population), others are ‘owls’ (late-risers, late to bed, 21 per cent of the population) — and the rest of us are ‘intermediates’, or neutral types, meaning we broadly conform with the social norm in terms of sleep and wake times.

Studies have shown that the greater the mismatch between an individual’s chronotype — the propensity to sleep or be active at particular times — and the time they are required to work, the greater their risk of developing health problems such as type 2 diabetes.

Employers could chronotype their workforce with a simple questionnaire and then attempt to match chronotypes to specific work schedules.

In simple terms, the larks would be better suited to the morning shifts and the owls to the night shifts.

Clearly, this is not the complete solution, but it could go a long way towards reducing some of the problems of shift work.