Intermittent or middle-of-the-night (MOTN) insomnia afflicts 10-40% of adults in the US population. It is characterized by nocturnal awakenings with difficulty in returning to sleep afterwards. Patients report a variety of causes for these awakenings, but objectively, 90% of clinically significant awakenings are preceded by an episode of altered breathing which fits the criteria for obstructive sleep apnea, or upper airway resistance syndrome. It is thought that the primary pathophysiology is not so much the momentary awakening as the constant state of hyperarousal which prevents the rapid resumption of sleep by racing or worrying thoughts that prolong the waking interval beyond a few moments.
Evaluation of this type of insomnia includes a careful study of sleep history to identify the problems in detail, as well as a history of any medical conditions, medication use, and looking for psychological or psychiatric conditions. It is important to offer customized treatment to each patient. If sleep hygiene is defective, the patient and family, or those who share the home or bedroom, should be educated in providing a proper sleep-promoting environment. This includes setting a regular bedtime, evolving a going-to-bed unwinding ritual, keeping the noise level low, turning off television and radio, and avoiding stimulation through excessive exercise or caffeine intake shortly before bedtime. Evaluation also includes sleep lab testing such as polysomnography and multiple sleep latency tests.
There are many modes of management of MOTN insomnia, and treatment should be tailored to meet specific needs. The effectiveness of each treatment is measured by whether it reduces the time to sleep onset, or increases sleep time by at least 30 minutes.
The non-pharmacologic treatment of MOTN insomnia includes a wide range of measures.
- Cognitive behavioral therapy
This is based on helping the patient to recognize and modify the pressuring and unpleasant thoughts associated with inability to go to sleep at once, and guidance in effecting appropriate behavioral changes. Individual or group sessions are conducted by follow-up. The aim is to reduce the arousal level of the patient, rather than just helping to increase the duration and the depth of sleep at night. It is highly effective, surpasses the effects of drugs, and has the additional advantage of having minimal adverse effects. Even if the sleep time remains the same, the patient is satisfied and unworried which has the same or better effect on health.
The following components are involved:
- Cognitive recognition of the type of thinking which made it harder to go to sleep, challenging these thoughts, and altering them, thus bringing about a calmer condition.
- Behavioral changes, such as sleep restriction and temporal control, stimulus control, and relaxation therapy. Sleep restriction is an intervention which limits time in bed to approximately the actual sleep time, thus limiting the time spent in bed thinking about going to sleep. This is linked with setting and keeping a regular and constant waking time in the morning to help adjust the circadian rhythm and so help bring about readiness for sleep within the body and the brain. It increases sleep efficiency and improves its restfulness.
- Stimulus control is a means of establishing a conditioned reflex in response to a time and a place, which helps the patients to form an association between sleep and the bed, as well as between bedtime and sleep. This involves keeping the bed apart for sleep only, other than physical intimacy; staying out of bed unless ready to fall asleep; leaving bed after 20 minutes if not already asleep, to do any quiet activity till drowsiness supervenes; and to do the same if waking in the middle of the night. This helps to mentally and emotionally sever the link between the bed and sleeplessness.
- Relaxation training helps the patient get ready for sleep by ensuring relaxed muscles, deep quiet breathing, and focusing the mind instead of letting it race or wander, leading to further arousal.
- Paradoxical intention where the patient focuses the mind on staying awake rather than going to sleep, helping ease the mental and emotional burden of sleeplessness and making sleep onset faster, has shown itself to be quite effective. The individual stops associating fears and worries with the awakening, which reduces the anxiety associated with the fear of failing to fall asleep at once.
- Imagery training is a means of stopping futile thoughts or focusing on peaceful or neutral images to help reduce the arousal level.
Sleep restriction, stimulus control, and cognitive recognition help more patients than other types of CBT techniques, though each may have its own role to play.
Other modes of treatment include:
- Stress-relieving measures
- Insight-oriented psychotherapy
- Bright light therapy which tries to reset the circadian rhythms by exposure to timed light
- Chronotherapy which corrects the sleep phase delay
Medications are used as the first-line approach in many cases because of the limited availability of CBT-trained personnel and the need for personal interactive sessions. The sedation they cause reduces the arousal state, thus improving night sleep. They have adverse effects, however, which limits their long-term use in many cases. Ideally, they should be used to bring about a rapid improvement in sleep over the short term while the patient is learning to use CBT techniques.
Benzodiazepines are hypnotic drugs which have been used traditionally to induce sleep, but their long duration of action and significant residual sedation have been cause for concern. They may cause amnesia and respiratory depression in some cases, as well as have addiction potential.
Nonbenzodiazepines include the sedative GABA-ergic agents such as zolpidem and the newer zaleplon which has a very short half-life (1.5 to 4 hours), as well as the melatonin receptor agonist trazodone.
Certain antidepressants which reduce the activity of the HPA axis have been used. These offer a better effect without rapid induction of tolerance, and have a better safety profile over the long term.
- Over-the counter medications
Patients with sleep-onset insomnia have traditionally taken sedating antihistamines (diphenhydramine and doxylamine) to hasten sleep onset, but they quickly induce tolerance, and often leave the patient sleepy or less alert the next morning as well. This is also a serious potential drawback of the benzodiazepines. The lingering effects of impaired muscular reflexes and coordination, with slowing of memory and a sense of fatigue, have dogged the use of most of these drugs.
Herbal preparations such as melatonin and valerian have been promoted for use in this condition primarily due to this concern. Melatonin is a hormone intimately concerned with the light-dark cycle and circadian rhythms, including sleep cycles. It is reduced by tobacco, alcohol, and many drugs. Its levels also go down with age. Valerian root, valeriana officinalis, is used for the central sedative action of its oil, which causes inhibition of GABA metabolism and induces sleep.
Alcohol is used as an aid to sleep but in excess it may cause the nocturnal awakenings, besides its propensity to fill the bladder and cause the need to void. Moreover, it is very likely to cause addiction.
Research is going on to find cytokine antagonists to reduce the stress-induced increases in these chemicals. Anti-inflammatory drugs may help improve sleep in the elderly MOTN insomniac, by relieving pain, and reducing fatigue. Coupled with these, sex steroid supplementation to reduce subclinical inflammation, and controlling weight gain by dietary and exercise-based intervention, may help correct insomnia as well as reduce the health risks of sleep deprivation.