Insomnia Disorder

How insomnia develops

Sleep depends on two systems: sleep pressure, which builds the longer you are awake, and the body clock (circadian rhythm), which times sleepiness for night. Insomnia happens when an arousal system (stress hormones, an active mind, a raised heart rate) overrides them.

Experts describe a "3P" model:

• Predisposing factors: a tendency to worry, anxiety, family history, older age and female sex.
• Precipitating factors: a trigger such as stress, illness, bereavement, a new baby or shift work.
• Perpetuating factors: the habits that keep it going after the trigger has passed, such as going to bed early to "catch up", lying in bed awake, napping, clock-watching, caffeine to get through the day and growing anxiety about not sleeping.

The perpetuating factors are what CBT-I targets.

Symptoms

Night-time

• Taking more than 30 minutes to fall asleep
• Waking during the night and staying awake more than 30 minutes
• Waking earlier than desired and being unable to return to sleep
• Feeling that sleep is light or unrefreshing

Daytime

• Fatigue and low energy
• Poor concentration, attention and memory
• Irritability and low mood
• Errors at work and an increased risk of accidents
• Tension headaches and stomach upset
• Worry and preoccupation about sleep

People with insomnia are often tired but not sleepy; they rarely nap easily. Strong daytime sleepiness suggests another sleep disorder such as sleep apnea.

Types of insomnia

The older term primary insomnia described insomnia with no other cause. Doctors now recognize that insomnia needs its own treatment even when another condition is present.

Causes and risk factors

• Stress, anxiety and depression
• Chronic pain and medical illness
• Menopause and pregnancy
• Shift work and jet lag
• Caffeine, alcohol, nicotine and some medicines
• Older age, with lighter, more fragmented sleep
• Coexisting sleep disorders: sleep apnea, restless legs syndrome and circadian rhythm disorders such as delayed sleep phase disorder

For a symptom-led look at reasons for sleeplessness, see trouble sleeping.

Diagnosis

Insomnia is diagnosed from your history. A doctor will ask about:

• your sleep schedule, bedtime routine and sleep environment
• how long it takes to fall asleep, how often you wake and when you wake for good
• daytime effects and naps
• mood, anxiety and stress
• medical conditions, medicines, caffeine, alcohol and substances
• snoring, breathing pauses and leg symptoms

A 2-week sleep diary is very useful. Questionnaires such as the Insomnia Severity Index measure severity. Polysomnography (an overnight sleep study) is not needed for insomnia itself, but is used when sleep apnea, periodic limb movements or other disorders are suspected. Blood tests may check thyroid function or iron stores where relevant.

Treatment

Cognitive behavioral therapy for insomnia (CBT-I)

The American College of Physicians and the American Academy of Sleep Medicine recommend CBT-I as the first-line treatment for chronic insomnia. It usually takes 4 to 8 sessions, in person, in groups, by video or through validated digital programs. Its components are:

• Sleep restriction: limiting time in bed to the actual time you sleep, then gradually extending it. This builds sleep pressure and consolidates sleep. It feels hard for the first 1 to 2 weeks.
• Stimulus control: using the bed only for sleep and sex, getting up if awake for about 20 minutes, and a fixed wake time.
• Cognitive therapy: challenging unhelpful beliefs such as "If I don't get 8 hours, tomorrow will be a disaster".
• Relaxation techniques: breathing exercises, progressive muscle relaxation and mindfulness.
• Sleep hygiene education: caffeine, alcohol, light and bedroom environment.

Around 70% to 80% of people improve with CBT-I, and the benefits last after treatment ends, unlike medicines.

Medicines

Medicines may be used short term, or when CBT-I is not available or not enough. Options a doctor might consider include:

• Z-drugs such as zolpidem: effective short term, but with risks of dependence, next-day impairment, falls and complex sleep behaviors such as sleepwalking.
• Orexin receptor antagonists such as suvorexant, lemborexant and daridorexant.
• Low-dose doxepin for sleep-maintenance insomnia.
• Melatonin receptor agonists such as ramelteon for sleep-onset insomnia.
• Benzodiazepines, now generally avoided because of dependence and falls.

Over-the-counter antihistamine sleep aids are not recommended for chronic insomnia, particularly in older adults. Melatonin has a small effect on insomnia and is most useful for body-clock problems. Alcohol worsens sleep quality.

Treating coexisting conditions

Treating depression, anxiety, pain, reflux, sleep apnea, restless legs or menopausal symptoms improves sleep, but insomnia often persists and still needs CBT-I.

Complications

• Higher risk of depression and anxiety
• Accidents at work and on the road
• Reduced work performance and quality of life
• Links with high blood pressure, heart disease and type 2 diabetes in people who sleep very little
• Dependence on sleeping medicines

Outlook

Short-term insomnia usually resolves once the trigger passes. Chronic insomnia can last for years if untreated, but CBT-I produces lasting improvement for most people. Relapses can happen in stressful periods; the techniques learned can be reused.

Frequently asked questions

What is the difference between insomnia and insomnia disorder?

Insomnia describes the symptom of trouble sleeping. Insomnia disorder is a diagnosis: sleep difficulty at least 3 nights a week, causing daytime problems, despite adequate opportunity to sleep. When it lasts 3 months or more, it is chronic insomnia disorder.

What is the best treatment for chronic insomnia?

Cognitive behavioral therapy for insomnia (CBT-I) is the recommended first treatment. It changes the habits and thoughts that keep insomnia going and works for most people, with benefits that last. Medicines can help short term but tend to lose effect and carry side effects.

Can insomnia be cured?

Many people with chronic insomnia recover fully or improve greatly with CBT-I. Insomnia can return during stressful times, but people who have learned CBT-I techniques can usually get back on track quickly without medication.

Does insomnia need a sleep study?

Usually not. Insomnia is diagnosed from your history and a sleep diary. A sleep study is recommended if your doctor suspects another sleep disorder, such as sleep apnea or periodic limb movements, or if treatment is not working as expected.

Is melatonin good for insomnia?

Melatonin has only a small effect on chronic insomnia in adults. It works best for shifting the body clock, such as jet lag or delayed sleep phase disorder. Supplements vary in strength. Talk to a doctor before giving melatonin to children or using it long term.