Classification

Physical

The physical examination can provide clues to comorbid insomnia.

• A large neck size of 18 inches or greater in males, elevated BMI of 30 kg/m², enlarged tonsils, Mallampati airway score of 3 or 4 (see Media file 2), low lying soft palate particularly in patients with hypertension or cardiac disease, and obstructive sleep apnea/hypopnea syndrome should be considered. Other features include enlarged tongue, retrognathia, micrognathia, or a steep mandibular angle.
• If patients have evidence of peripheral neuropathy (ie, stocking distribution loss of temperature sensation) with or without trophic changes, they should be asked about painful symptoms (ie, burning sensation) in their feet, and history of diabetes, alcohol abuse, and neurologic consultation should be requested.
• If patients complain of symptoms of restless legs syndrome or symptoms suggestive of a neurologic disorder, such as nocturnal seizures, Parkinson disease, or a neuromuscular disorder, a neurologic consultation should be requested.
• In patients with chronic pain syndromes or rheumatologic syndromes, referral to a pain management specialist and/or rheumatologist should be considered.
• If chest examination shows reduced breath sounds; clubbing or wheezing in the setting of clinical signs; and symptoms suggestive of chronic obstructive pulmonary disease, asthma, or obesity hypoventilation syndrome, pulmonary consultation should be requested.

Causes

Many clinicians often assume that insomnia is secondary to a psychiatric disorder, However, a large epidemiologic survey showed that half of insomnia diagnoses were not related to a primary psychiatric disorder. As mentioned earlier, an insomnia diagnosis does increase the future risk for depression or anxiety (see Morbidity).

Frequency of insomnia causes.

Classification of Insomnia

The International Classification of Sleep Disorders classifies insomnia into 11 categories, listed below.

Adjustment insomnia (acute insomnia)

This occurs in the context of an identifiable stressor (eg, personal loss, change in interpersonal relationship, bereavement, occupational stress, job loss) that acts as a precipitating factor. It typically last 3 months or less and resolves as the stressor is no longer present or as the individual adapts to the stressor .

Chronic insomnia

The following are diagnoses of chronic insomnia and meet the criteria for chronic insomnia:

1. Repeated difficulty with the initiation, duration, maintenance, or quality of sleep that occurs despite adequate time and opportunity for sleep that results in some form of daytime impairment.
2. Number 1 must be present for at least 1 month.

Psychophysiologic insomnia (primary insomnia)

• The patient has evidence of conditioned sleep difficulty and or/heightened arousal in bed as indicated by one or more of the following:
  • Excessive focus on and heightened anxiety about sleep
  • Difficulty falling asleep at the desired bedtime or during planned naps, but no difficulty falling asleep during other monotonous activities when not intending to sleep
  • Ability to sleep better away from home than at home
  • Mental arousal in bed characterized either by intrusive thoughts or a perceived inability to volitionally cease sleep-preventing mental activity
  • Heightened somatic tension in bed reflected by a perceived inability to relax the body sufficiently to allow the onset of sleep
• The sleep disturbance is not better explained by another sleep disorder, medical or neurologic disorder, medication use, or substance abuse disorder.

Paradoxical insomnia

• One or more of the following criteria apply:
  • The patient reports a chronic pattern of little or no sleep most nights, with rare nights during which relatively normal amounts of sleep are obtained.
  • Sleep log data from one or more weeks of monitoring show an average sleep time often with no sleep at all indicated for several nights each week; typically daytime naps are absent following such nights.
  • The patients typically show a mismatch between objective findings from polysomnography or actigraphy and subjective sleep estimates from self-reported sleep diary.
• At least one of the following is observed:
  • The patient reports constant or near constant awareness of environmental stimuli throughout most nights.
  • The patient reports a pattern of conscious thoughts or rumination throughout most nights while maintaining a recumbent posture.
• The daytime impairment reported is consistent with that reported by other insomnia subtypes but is much less severe than expected given the extreme level of sleep deprivation reported.
• The sleep disturbance is not better explained by another sleep disorder, medical or neurologic disorder, medication use, or substance abuse disorder.

Insomnia due to medical condition

• The patient has a coexisting medical condition known to disrupt sleep.
• The insomnia is clearly associated with the medical condition. The insomnia began near the time of onset or with significant progression of the medical condition and waxes and wanes with the severity of this condition.
• The sleep disturbance is not better explained by another sleep disorder, medical or neurologic disorder, medication use, or substance abuse disorder.

Insomnia due to mental disorder

• A mental disorder has been diagnosed according to the criteria of DSM-IV-TR.
• The insomnia is temporally associated with the mental disorder; however, in some cases, insomnia may appear a few days or weeks before the emergence of the underlying mental disorder.
• The insomnia is more prominent than that typically associated with the mental disorders, as indicated by causing marked distress or constituting an independent focus of treatment.
• The sleep disturbance is not better explained by another sleep disorder, medical or neurologic disorder, medication use, or substance abuse disorder.

Insomnia due to drug or substance abuse

• One of the following applies:
  • The patient has current ongoing dependence on or abuse of a drug or substance known to have sleep disruptive properties either during periods of use or intoxication or during periods of withdrawal.
  • The patient has current ongoing use of or exposure to a medication, food, or toxin known to have sleep-disruptive properties in susceptible individuals.
• The insomnia is temporally associated with the substance exposure, use, or abuse, or acute withdrawal.
• The sleep disturbance is not better explained by another sleep disorder, medical or neurologic disorder, medication use, or substance abuse disorder.

Insomnia not due to substance or known physiological condition, unspecified

This diagnosis is used for forms of insomnia that cannot be classified elsewhere in ICSD-2, but are suspected to be due to an underlying mental disorder, psychological factors, or sleep disruptive processes. This diagnosis can be used on a temporary basis until further information is obtained to determine the specific mental condition or psychological or behavioral factors responsible for the sleep difficulty.

Inadequate sleep hygiene

• Inadequate sleep hygiene practices are evident by the presence of at least 1 of the following:
  • Improper sleep scheduling consisting of frequent daytime napping, selecting highly variable bed or rising times or spending excessive amounts of time in bed.
  • Routine use of products containing alcohol, nicotine, or caffeine, especially in the period preceding bedtime.
  • Engagement in mentally stimulating, physically activating, or emotionally upsetting activities too close to bedtime.
  • Frequent use of the bed for activities other than sleep (eg, television watching, reading, studying, snacking, thinking, planning).
  • Failure to maintain a comfortable sleeping environment.
• The sleep disturbance is not better explained by another sleep disorder, medical or neurologic disorder, medication use, or substance abuse disorder.

Idiopathic insomnia

A longstanding complaint of insomnia with insidious onset in infancy or childhood. No precipitant or cause is identifiable. There is a persistent course with no sustained periods of remission. This condition is present in 0.7% of adolescents and 1% of very young adults.

Behavioral insomnia of childhood

• A child's symptoms meet the criteria for insomnia based on parents or other adult caregivers observations.
• The child shows a pattern consistent with either sleep-onset association or limit-setting type of insomnia:
  • Sleep onset association type
    • Falling asleep is an extended process that requires special conditions.
    • Sleep onset associations are highly problematic or demanding.
    • In the absence of associated conditions, sleep onset is significantly delayed or sleep is otherwise disrupted.
    • Nightime awakenings require caregiver intervention for the child to return to sleep.
  • Limit-setting type
    • The individual has difficulty initiating or maintaining sleep.
    • The individual stalls or refuses to go to bed at an appropriate time or refuses to return to bed following a nighttime awakening.
    • The caregiver demonstrates insufficient or inappropriate limit setting to establish appropriate sleeping behavior in the child.

Primary sleep disorders causing insomnia

• Restless legs syndrome (RLS) is a sleep disorder characterized by the following:
  • An urge to move the legs, usually accompanied by uncomfortable and unpleasant physical sensations in the legs.
  • The urge to move or the unpleasant sensations begin or worsen during periods of rest or inactivity such as lying or sitting.
  • The urge to move or the unpleasant sensations are partially or totally relieved by moving, such as walking or stretching, at least as long as the activity continues.
  • The urge to move or the unpleasant sensations are worse or only occur in the evening or the night.
• Obstructive sleep apnea/hypopnea syndrome:A minority of patients complain of insomnia rather than hypersomnolence. They frequently complain of multiple awakenings or sleep-maintenance difficulties. They may also have nocturia causing frequent nocturnal awakenings.
• Circadian rhythm disorders
  • Advanced sleep phase syndrome: The patient feels sleepy earlier than their desired bedtime (ie, 8 pm) and they wake up earlier than they would like to (ie, 4-5 am). This condition is more common in the elderly. These patients typically complain of sleep maintenance insomnia.
  • Delayed sleep phase syndrome: The patient does not feel sleepy until much later than the desired bedtime, and he or she wakes up later than desired or socially acceptable. On sleep diaries or actigraphy, these patients show a consistent sleep time with earlier wake times that correspond to school or work days, and delayed wake times on weekends, time off, and vacations. This condition often begins in adolescence and may be associated with a family history in up to 40% of patients. These patients report difficulty falling asleep at usually socially desired bedtimes, and complain of excessive daytime sleepiness during the school or work week.
  • Shift work sleep disorder: A complaint of insomnia or excessive sleepiness is typically temporally related to a recurring work schedule that overlaps the usual sleep time. This can occur with early morning shifts (4-6 am), where the patient is anxious about waking up in time for their early shift particularly when they have a rotating shift schedule. Evening shifts that end at 11 pm can result in insomnia in that the patient may need some time to wind down from work before retiring to bed. Night shift can be associated with both sleep onset and maintenance insomnia due to exposure to sunlight on their drive home from work, daylight exposure in their bedroom, and social and environmental cues (picking up children at school, paying bills, household chores, etc).
  • Irregular sleep-wake rhythm: This is typically seen in patients with poor sleep hygiene, patients who live or work alone with minimal exposure to light, activity, and social cues. These patients randomly nap throughout the day making it difficult, if not impossible, to fall asleep at a habitual bedtime with a consolidated sleep period.

History

History

The history is the most important part of evaluating insomnia. It must include a complete sleep history, medical history, psychiatric history, social history, and careful medication review.

Sleep history

Determining the timing of insomnia, the patient's sleep habits (commonly referred to as sleep hygiene), and symptoms of sleep disorders associated with insomnia is important.

• Timing of insomnia: Patients should be asked about any difficulty falling asleep, frequent or early morning awakening, problems in sleep onset, and whether they feel sleepy when getting into bed.
• Sleep schedule: Patients must be asked what time they go to bed and rise from bed in the morning. Determine whether the sleep schedule is consistent and if the schedule has changed recently.
• Sleep environment: Patients should be asked about temperature, bed comfort, noise, and light levels. Ask whether the patient sleeps better in his or her own bed or in a chair or a foreign environment (like a hotel).
• Sleep habits: Patients with insomnia often have poor sleep hygiene. They should be asked about activities prior to bedtime (ie, relaxation or work), whether they read or watch TV in bed, and whether the TV or light is kept on during the night. Also, ask patients what they do if unable to fall asleep and whether they fall asleep after waking up in the middle of the night. Ask patients about daytime naps and whether they exercise and the time of exercise.
• Patients should be asked about symptoms of other sleep disorders such as obstructive sleep apnea (eg, snoring, witnessed apneas, gasping) and restless legs syndrome/periodic limb movement disorder (ie, restless feeling in legs on lying down, which improves with movement; rhythmic kicking during the night; sheets in disarray in the morning).
• Daytime effects: Patients should experience daytime effects if they truly are not sleeping at night. In fact, if a patient is having no daytime effects, he or she is probably getting adequate sleep and the complaint of insomnia is truly subjective. Common complaints are fatigue, tiredness, lack of energy, irritability, reduced work performance, and difficulty concentrating. These complaints should be distinguished from the complaint of excessive sleepiness, which is uncommon in insomnia. For example, if a patient complains of excessive daytime sleepiness (ie Epworth Sleepiness Scale Score >10), another sleep disorder should also be considered. (See Media file 12 for the Epworth Sleepiness Scale.)

Medical history

A thorough medical history and review of systems should be performed, with particular emphasis on those disorders mentioned in Causes.

Psychiatric history

A review of signs and symptoms of anxiety or depression should be sought. A 2-question case-finding instrument can help screen for depression.

Diagnostic algorithm for major depression.

Diagnostic criteria for generalized anxiety disorder.

Social history

For transient or short-term insomnia, inquire about new situational stresses such as a new job, new school, relationship change, or bereavement. For chronic insomnia, attempt to relate the onset of insomnia to past stresses or medical illnesses. Inquire about tobacco, caffeinated products, alcohol, and illegal drug use.

Medication history

Medications that commonly cause insomnia include beta-blockers, clonidine, theophylline (acutely), certain antidepressants (protriptyline or fluoxetine), decongestants, and stimulants. Also inquire about over-the-counter and herbal remedies that the patient may be taking.