What is Insomnia?
It is perfectly normal for people to feel dissatisfied by their sleep from time-to-time and the word ‘insomnia’ is thrown around a lot but – how is insomnia defined?
Diagnostic Criteria
The diagnostic criteria for insomnia are listed in the Diagnostic and Statistical Manual (DSM), the manual used by clinicians and researchers to diagnose and classify mental disorders. In the fifth edition, published in May 2013 (DSM-5), insomnia disorder is defined as a combination of both dissatisfaction with sleep and a significant negative impact on daytime functioning.
Dissatisfaction with sleep is further defined as difficulty initiating and/or maintaining sleep or non-restorative sleep, on at least three nights per week for at least 3 months, despite adequate opportunity to sleep. Negative daytime impacts can include significant fatigue, sleepiness, poor concentration, low mood, or impaired ability to perform social, occupational or caregiving responsibilities.
Insomnia as a target for intervention, not just a symptom
The traditional view, which was reflected in earlier editions of the DSM, was to define insomnia as either primary (i.e. no other conditions deemed to be responsible for the poor sleep) or secondary (i.e. another disorder causally responsible for the poor sleep). In practice determining cause and effect is very difficult, if not impossible. Bidirectional or interactive effects between insomnia and certain co-existing conditions, such as depression, are now widely accepted. Importantly, DSM-5 removed the primary and secondary causal attribution labels. ‘Insomnia disorder’ is now recognized as a condition requiring independent clinical attention, regardless of other medical problems that may be present.
Causes of insomnia – “why can’t I sleep?”
It would be great to think that insomnia had a single cause! It usually does not – The ‘3 Ps’ model, designed to help people understand the development and persistence of health problems, was brought into research on poor sleep by Dr Art Spielman in the 1980s. The three Ps stand for ‘predisposing’, ‘precipitating’ and ‘perpetuating’ factors:
Predisposing factors
A predisposition does not ‘cause’ a problem but may increase the likelihood of it occurring. When thinking about insomnia these could include having a family history of poor sleep, generally being a ‘worrier’ or never having been a ‘good sleeper’, for example.
Precipitating factors
Another word for these could be ‘triggers’ and may include such things as lifestyle changes, a house move or promotion at work, the development of an illness or birth of a baby for example. Indeed a study published in 2004 found that 60% of patients with insomnia could identify a trigger for their sleep disturbance, and these tended to be around family, work/school and health (Bastien et al. 2004).
Perpetuating factors
These would cover any factors which might be seen to maintain or even exacerbate the problem e.g. heightened anxiety/arousal levels for or the development of depression which may represent barriers to recovery. It may also be the case that behaviors or coping strategies (e.g. napping during the day spending excessive amounts of time in bed), developed and implemented over time are involved in the maintenance of insomnia. Thus, insomnia could become learned over months and years, even though the initial stressor that may have been involved in its development has disappeared.
Treatments for insomnia
Following the 3 Ps model, it is clear that perpetuating factors, due to their presumed role in maintaining insomnia, are good candidates for intervention. Indeed this is exactly what Cognitive Behavioral Therapy (CBT-I) attempts to do; targeting maladaptive sleep behaviors and cognitions that are characteristic of insomnia. Other treatments like sleeping pills, may similarly target core features of insomnia, like the racing mind, but at a different level (usually in terms of alterations to neurochemicals involved in the regulation of sleep and arousal, like GABA).
Poor sleepers' impact on their bed partners
Although poor sleep is very common, it's not at all uncommon to find that someone with persistent sleep problems has a partner that sleeps well. This often creates an extra challenge for poor sleepers with partners – feeling isolated as a result of their sleep problem, being reminded that others are asleep whilst they are awake…by someone being soundly asleep right next to them! Perhaps when both partners have sleep problems they are able to provide mutual support and work through solutions together?
One of the areas that poor sleep often has a negative effect on is relationships, and it's easy to see how disrupted sleep can put a strain on the person you share a bed with. In the short term the techniques in the course can also be disruptive – especially those focussed on reconnecting your bed with sleep and restricting your sleep window. It might be that your partner finds it hard to understand the techniques included in the course, and how they are intended to make improvements to your sleep. In this case communication is often the best solution. Try sharing the program with them, explain that this is a temporary period of disruption that should lead to a long-term ongoing improvement. In fact, why not let them know how they can help you – reminding you to practice the relaxation techniques for example, or just taking a more light-hearted approach to the problem!
Beyond this it could be worth considering practical solutions to disrupting your partner's sleep – sleeping in separate rooms for the duration of the course, or buying a soundless, vibrating alarm clock that you can place under your pillow to wake you at your rising time. However, long term poor sleepers have often exhausted many of these 'coping strategies', and the better solution is to bite the bullet and put the course into action for a limited time with their (perhaps reluctant!) blessing.
Sleepiness, fatigue and impaired concentration
“Why am I tired all the time?”
We all experience poor (or restricted) sleep from time-to-time and therefore are familiar with its consequences on our daytime functioning. Among the most common are fatigue and sleepiness. Although we might use these terms synonymously, they technically refer to different (though clearly related) things. Sleepiness reflects one's propensity to fall asleep (or inability to stay awake), while fatigue refers to lethargy, or an inability to maintain levels of performance on a given task. In studies where healthy subjects have been sleep deprived (totally or partially), both objective and subjective measures of fatigue and sleepiness tend to increase, and for those whose sleep has been restricted in duration (e.g. from 8 to 4 hours) over several days (e.g. 5 days), sleepiness and fatigue have been shown to increase with each day of accumulated sleep loss (Banks et al., 2010). Indeed fatigue may not be fully overcome after a full night of (recovery) sleep.
Often we may experience both fatigue and sleepiness after sleeping poorly, and sometimes we may experience just one of these in isolation. For those with insomnia, fatigue (sometimes also referred to as reduced energy) is the most characteristic daytime complaint. Problems with sleepiness, on the other hand, may not be as common. A recent study assessed daytime sleepiness in patients diagnosed with insomnia disorder (Roehrs et al, 2011). They used what's called the multiple sleep latency test (MSLT). The MSLT involves providing patients with 4 nap opportunities throughout the course of a day. Sleepiness is measured as the time taken to fall asleep during the nap. Interestingly, despite sleeping more than an hour less than healthy control subjects, the night before, patients with insomnia disorder took longer to fall asleep (by about 2 minutes, on average) during the day. This suggests that patients with insomnia have difficulty falling asleep and reducing arousal both during the day and night. On the other hand, sleep apnoea patients, who often report excessive daytime sleepiness, take less time to fall asleep during the MSLT daytime nap, providing objective evidence of increased daytime sleep propensity. This difference can be very important in day-to-day clinical practice; helping medical professionals tease out what sleep disorder an individual may be suffering from.
Both increased sleepiness and fatigue are associated with the inability to concentrate or 'think clearly'. Indeed, along with impaired energy/fatigue and mood, concentration is one of the most common daytime issues reported by patients with insomnia disorder – this is what was found in the recent Great British Sleep Survey. This inability to concentrate might reflect an issue with sustained attention or shifting attention. In studies where sleep-deprived subjects have been tested after sleep loss, it is commonly the case that they will take longer to respond to a stimulus that appears on the screen (and experience more attentional lapses; failing to respond within a certain time interval). A study in insomnia patients found that a complex attention task – where subjects had to respond on a computer screen to the letter 'p' but not the letter 'd' – revealed impairments in reaction time to making this judgment. Intriguingly, patients were treated with a non-pharmacological treatment (which included cognitive behavioral therapy) and found to improve in performance post-treatment.
Indeed, there is emerging evidence that CBT-I improves a wide array of daytime impairments in those with chronic sleep disturbance (Kyle et al., 2010). For example, studies that have investigated health-related quality of life, have found that improvements in night-time sleep, through treatment, have also been accompanied by improvements in daytime functioning, particularly areas that are fatigue-related.
Irritability, anxiety and flattened mood
A common research finding is that next-day emotional functioning is compromised if one has not obtained adequate sleep the night before. You may well have found yourself 'snapping' at a friend or colleague, or becoming easily irritated after a poor night of sleep. This change in emotional stability is consistently found in those who have been experimentally sleep-deprived, and in those with chronic sleep disorders. The recent Great British Sleep Survey (GBSS), found that flattened mood was the second most frequently reported daytime consequence of chronic poor sleep. Healthy participants who have been sleep-deprived also show reductions in next-day positive mood. Following healthy older adults, over several days, it was found that greater wake time during the night and poorer ratings of sleep quality were associated with reductions in next-day positive mood and increases in next-day negative mood (McCrae et al., 2008).
It is also the case that poor sleep is more frequently found in disorders that are characterized by problems with regulating emotion (e.g. depression, anxiety). This led to the traditional view that insomnia was simply a consequence of the so-called 'primary' (usually psychiatric) problem. However, research has shown that sleep-restricted healthy subjects, as well as patients free from psychiatric illness, but with chronic sleep disturbance, also show impairments in emotional well-being. This suggests a possible primary role for sleep in regulating next-day emotional responses.
An elegant example of this can be found in a recent study by a research group at the University of California, Berkeley. Here, healthy participants were split into two groups: one group viewed emotionally-arousing images in the morning and again later in the evening, each time whilst simultaneously having their brain scanned. A second group similarly viewed the images, firstly in the evening before sleep and then in the morning after sleep. Thus the main factor that differentiated the groups was that one group slept in-between testing sessions, while the other did not. It was found that in the group that slept between the two presentations of images, there was a reduction in brain activity in regions of the brain responsible for emotional processing towards emotionally arousing images, relative to the group that were awake between sessions. Moreover, the magnitude of the decrease in brain (re)activity between testing sessions, in the group that slept, was related to the amount of REM sleep-related brain activity. Changes were also found in the subjective intensity of images, indicating that those who had slept rated the images as less intense after sleep. The authors therefore concluded that sleep, in particular REM sleep, may be important in restoring next-day emotional balance (Van der helm et al., 2011).
Related to this work, researchers have questioned whether improving sleep may therefore improve aspects of mood and emotional well-being. A study published in 2008 found that improving sleep in those with depression, using CBT-I, was associated with greater depression remission rates, relative to a control group. Face-to-face CBT-I studies in those with so-called primary insomnia (free from additional medical or psychiatric problems) have similarly documented improvements in aspects of mental health and well-being. Indeed, scientific evaluation of the Sleepio course found, at two months post-treatment, that mood improved relative to a placebo group and waitlist control group.