科学家如何改变了他们对失眠的看法

Insomnia may have been torturing humanity since ancient times, but over the last 20 years scientists have made progress in their understanding of chronic sleep deprivation.

Today, sleep deprivation is one of the most widespread reported psychological problems in Britain, with about a third of the adult population in England reporting frequent insomnia symptoms.

Insomnia rarely occurs on its own, which brings us to one of the biggest changes scientists have made in our understanding of chronic sleep deprivation. The vast majority of people with insomnia often have other mental and physical health conditions, like diabetes, hypertension, chronic pain, thyroid disease, gastrointestinal problems, anxiety or depression.

In its diagnostic history, insomnia coupled with another illness or disorder was called secondary insomnia. That meant that insomnia was considered a consequence of those other underlying conditions. As such, until fairly recently doctors did not generally attempt to treat secondary insomnia.

But in the early 2000s, both research and clinical practice evidence started to indicate that this approach was wrong. Scientists argued that insomnia could precede or long survive a primary condition. Abandoning this distinction between primary and secondary insomnia was a major advance in acknowledging that insomnia frequently was an independent disorder, requiring its own treatment.

What’s more, researchers have been accumulating strong evidence that helping people with their sleeping problems could actually lead to improvements in their other health conditions. Chronic pain, chronic heart failure, depression, psychosis, alcohol dependency, bipolar disorder, PTSD, can all improve for patients if they address their sleeping problems.

Who gets insomnia?

Over the past two decades, we have acquired more rigorous and international data illustrating how ubiquitous insomnia is. Insomnia affects almost everyone, though women, older people, and people of lower socio-economic status are more vulnerable to it.

These groups experience a combination of biological, psychological and social risk factors that expose them to long-term sleep-disruption. For example, women often experience acute hormone fluctuations, pregnancy and birth, breastfeeding, menopause, domestic violence, caregiving roles, higher prevalence of depression and anxiety – all of which can lead to more opportunities for prolonged sleep disruption.

Some current issues in insomnia research include the need to understand different types of insomnia symptoms, and their relationship to health and performance risks. For example, there is evidence that difficulty initiating sleep (as opposed to difficulty staying asleep, or waking up too early in the morning) is associated with an increased risk of depression. Similarly, scientists still have questions on changes in things like brain activity, heart rate, or stress hormones that accompany insomnia. In common with all other mental health disorders, we are still yet to find biomarkers of insomnia.

However, research has helped us understand some things people can do to prevent insonmia episodes progressing to chronic insomnia, which is harder to treat. When insomnia symptoms happen more nights than not, and last for more than three months, then a diagnosis of insomnia disorder, or chronic insomnia, can be made.

One of the most common and harmful habits that develop during periods of insomnia is lying in bed, trying to sleep. Scientists have learned that lying in bed awake leads to perpetual cognitive arousal and, in time, it teaches your brain to stop connecting bed and being asleep.

Thus, if you cannot sleep at night, get up and do something else absorbing, but calming – read, write a list for the following day, listen to calming music or do some breathing exercises. When you feel sleepy again, get back to bed. If you are tired the following day, a well-placed short nap is fine, in the afternoon, for a maximum of 20 minutes. However, one must be careful with daytime sleeping, as it may reduce sleepiness at nighttime, and going to sleep may become even more difficult.

For those who do struggle with insomnia, there are effective treatments recommended. The story of the profound changes from secondary insomnia to insomnia disorder speaks of the power of clinical diagnosis in providing a pathway to treatment.

Cognitive behavioural treatment for insomnia (CBTI) is a package of techniques designed to maximise sleepiness at bedtime. It involves structured steps which aim to modify behaviour and mental activity. There are some predictors of treatment success : shorter duration of insomnia symptoms (years, rather than decades), less depression or pain and more positive expectations towards CBTI. But CBTI is broadly effective across all groups of people with insomnia.

Even so, only a tiny proportion of people reporting insomnia symptoms seek medical help. People may consider insomnia symptoms trivial or manageable, or they may be unaware of the options. It may also be due to the unavailability of treatment options. CBTI remains largely unavailable in clinical practice, mainly due to doctors’ unfamiliarity with the treatment programme, and limited funding.

This pushes patients towards sleeping tablets, which are not an acceptable long-term solution. Sleeping tablets are associated with significant cognitive and motor impairment, increased risk of falls, dependence, tolerance and withdrawal symptoms, daytime lethargy, dizziness and headaches.

The main truly “new” class of sleeping pills are the dual orexin receptor antagonists (DORAs), which have shown a safety profile in many ways better than the traditional sedatives, especially around dependence concerns. But DORAs are not risk free or “mild” pills. They are relatively new to the market, first approved in the UK in 2022. So we lack long-term data to assess their safety for long-term use in people with insomnia.

A decent alternative is online self-delivered CBTI, on platforms such as Sleepful, which are free to access.

We have made great strides in sleep medicine over the past 20 years for people with insomnia, we just need to realise the potential of such profound changes by providing the right help for those suffering with it.

Iuliana Hartescu receives funding from the Medical Research Council; the Engineering and Physical Sciences Research Council.