A fifth of Britons get less than five hours sleep a night and mental health disorders are suffered by a startling one in four people. Up to now, most doctors have assumed mood problems inevitably lead to sleep problems – if you’re depressed you can’t sleep. Now, a growing body of evidence suggests insomnia could actually cause psychological problems, most notably depression, which affects 10 per cent of Brits, most of them women.
Two thirds of people with mental health problems also sleep badly. But while the idea that prolonged periods of severe insomnia could lead to mood problems like depression was still in its infancy 20 years ago, studies since seem to confirm it.
‘Traditionally, sleep difficulty has been regarded as a secondary consequence of psychiatric disorders, but overlooked as a cause,’ says Dr David Freeman, clinical psychologist at the Institute of Psychiatry, King’s College London.
‘Now there is compelling evidence suggesting that having difficulty getting to sleep or staying asleep can be a contributing factor in the development of later problems, particularly depression. Insomnia can be both a consequence and a cause of mood disorders’.
As early as 1987, scientists at John Hopkins University in Baltimore followed 1053 medical students for 34 years after graduation and found that 101 of them developed clinical depression. The students that had trouble sleeping were twice as likely to go on and develop depression in later life. 20 years later in 2007, a study conducted in Staffordshire and published in the journal Sleep followed 4885 people for 12 months and found that 15 per cent of those who had insomnia for the entire year also reported anxiety or depression. In a concurrent study, research [also published in the journal Sleep] on 25,000 Norwegian adults carried out at Haukeland University Hospital first surveyed people in the mid-eighties and then again in the mid-nineties and found that 95 per cent of those who had chronic insomnia during the first survey also had anxiety disorders during the second.
According to Gaby Badre, sleep medicine consultant and professor of clinical neuroscience at the London Clinic, one third of people who experience serious insomnia for a prolonged period are at risk of going on to develop depression. ‘People suffering disturbed sleep may be suffering from an early warning that a subsequent depression may develop,’ he says.
That’s not to say that all people with sleeping problems will develop depression. ‘Insomnia is never enough on its own,’ says Dr Freeman. ‘Every night one in three people have difficulty getting to sleep but only a small proportion of those will experience a subsequent psychological consequence. What prolonged lack of sleep can do is make people more vulnerable to later problems in mood.’
Few people will dispute the fact that a few consecutive nights disturbed asleep can affect how we feel during the day. But exactly how prolonged insomnia may cause mood problems is not fully understood. One theory is that it relates to a complex nocturnal web of hormones and brain chemicals that our bodies maintain and balance while we sleep; a web that’s inextricably linked to our mental health.
Even moderate changes in sleep times can have an effect on mood. Last year, a study also in the journal Sleep at The Centre of The Treatment and Study of Circadian Rhythms at Douglas Mental Health University Institute in Montreal found that serotonin levels – a key substance for mood stability – were lower in shift workers than in day workers.
‘Repeatedly disturbed sleep can make people more vulnerable to developing mood disorders by disturbing circadian rhythms or the natural biological clock that governs sleep-wake cycles,’ says Professor Paul Keedwell, consultant psychiatrist and expert on depression at the Institute of Psychiatry, King’s College London.
Among one of the possible causes is disturbed levels of the hormone melatonin, thought to play a key part in controlling sleep-wake rhythms and how our bodies respond to day and night.
‘Sleep is an essential process,’ says Professor Badre. ‘If we don’t sleep we die, because sleep is the time that our bodies recover physically and emotionally from the day’s events.’ Studies in the 1970s showed that rats deprived of sleep completely were all dead within 20 days.
We go through three phases of sleep, explains Professor Badre. Light sleep, deep sleep and Rapid Eye Movement or REM sleep. Each type activates different neurotransmitters, which are brain chemicals central to mental functioning. Each phase lasts between 60 and 90 minutes and during a typical full nights sleep that cycle might repeat up to six times.
Meanwhile, there are two different types of insomnia – trouble getting to sleep and trouble staying asleep. People who suffer with or later go on to develop depression often fall into the second category, those who can’t stay asleep, as processes the body carries out during sleep – essential to neurological health – are repeatedly interrupted.
‘For example, when you enter phase two, deep sleep the body releases key hormones,’ explains Professor Badre. ‘Chief among these is growth hormone, which balances out stress hormones such as adrenaline and cortisol that accumulate during the day.’ If we have a shortage of deep sleep, our bodies don’t get the time to release and balance all these hormones so the result is waking up with an excess of stress hormones in the body – morning grumpiness.
‘If you are physically healthy, you can compensate by using up those excess hormones during the day. But if you have a tendency towards psychological problems, or other risk factors such as stress at work, the effects of this lack of sleep could – over time – act as a trigger towards mood problems.’
REM sleep on the other hand, is thought to be responsible for information, emotion and memory processes and typically waking up in this phase of sleep, could also lead to emotional difficulties.
In a study at the University of California, psychologists showed people pictures of faces expressing different emotions such as fear, anger, sadness and happiness and asked them to rate how emotional they thought each face was. They did this at midday and again at 6pm and in the second session, participants reacted more negatively to angry and fearful faces.
However, half of the volunteers were allowed to take a 90 minute nap at lunchtime in which they managed to achieve REM sleep (researchers did brain scans as they slept) and those not only didn’t react negatively to the angry or sad pictures, they were also more receptive to the happy ones.
A massive 60 per cent of people with a sleep disorder have never visited their doctor for advice or treatment (despite for some, having suffered for 12 years), and one third believe that nothing can be done about it. Some researchers now speculate that getting help for insomnia early may prevent some of us from developing depression.
Could sleeping pills help? ‘There is no doubt that benzodiazepines such as Diazepam or Temazepam, typically prescribed for sleep problems lead to dependency, so it’s never advisable to take them for longer than two weeks,’ says Professor Badre.
According to Dr Adrian Williams, Consultant Physician and Director, Lane-Fox Respiratory Unit & Sleep Disorders Centre, St Thomas’ Hospital, London and director of the London Sleep Centre, the idea that prolonged sleep problems could later lead to both depression and mood problems is now ‘an accepted one in sleep medicine’. The most effective early non-drug treatment he says, is Cognitive Behavioural Therapy or CBT specifically for insomnia.
CBT is a psychological therapy that teaches people to change their habitual behavioural and thought patterns and a large body of evidence has shown that it helps sleep problems long term.
‘Studies have shown that in six CBT sessions, insomnia can be improved,’ says Dr Freeman, who is currently piloting a study looking at the possibility that CBT treatment for insomnia could help patients with the symptoms of paranoia.
‘Up to now, all the studies on insomnia and CBT have treated the sleeplessness in isolation. What we need now are further studies to help determine whether treating early signs of insomnia with CBT could reduce the later risk of depression, anxiety and mood disorders. The next phase of research will focus on that.’
COULD YOU BE AT RISK?
Don’t panic. The chances that your insomnia will trigger depression are low. But certain signs may indicate an increased risk:
- If the insomnia has lasted most nights for 12 weeks or more
- If you have other risk factors such as prolonged stress at work, bereavement or other stressful event as well as sleep problems.
- If you experience repeated tiredness and grumpiness in the mornings, hyperactivity during the day, an inability to get to sleep, and a pattern of waking in the very early nocturnal hours.
If you are experiencing a prolonged period of insomnia speak to your GP about a referral to sleep clinic or CBT therapist.
HOW TO GET A GOOD NIGHT’S SLEEP
Keep regular hours Going to bed and getting up at the same time everyday, even at weekends will help program your sleep-wake cycle.
Create a restful sleeping environment Keep the bedroom for rest, sleep and sex. Make sure the temperature is not too warm or cold and as quiet and dark as possible.
Take more exercise during the day, preferably outside during daylight (natural light helps set your body clock) – but not too close to bedtime or it couyld kep you awak.
Cut down in caffeinated beverages after 2pm Try a hot milky drink or herbal tea in the evening.
Don’t smoke Nicotine, especially before bed os a stimulant and smokers take longer to fall asleep.
Don’t obsess about it If you can’t sleep, get up and do something relaxing such as reading, until you feel sleepy again.
If you use the alarm, turn it around to face the wall (or put it under the bed). Clock-watching can increase insomnia.
If you do wake up to go to the loo, try not to put on any lights The hormone that helps you sleep, melatonin, is produced when it’s dark. Going from bright light or a flickering TV straight to bed can make it hard to sleep so spend some time relaxing in dim lights before bed.
More information sleepcouncil.org.uk
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