Careful investigation can often reveal insomnia’s cause1—whether a medical or psychiatric condition or poor sleep habits. Understanding why patients can’t sleep is key to effective therapy.
Insomnia is associated with increased risk of accidents, work-related difficulties, and relationship problems.2 Long-term sleeplessness may even increase risk of new psychiatric disorders—most notably major depression.3
Primary Insomnia
DSM-IV-TR criteria for primary insomnia include:4
- For at least 1 month, the patient’s main complaint has been trouble going to sleep, staying asleep, or feeling unrested.
- The insomnia or resulting daytime fatigue causes clinically important distress or impairs work, social, or personal functioning.
- The insomnia does not occur solely in the course of a breathing-related or circadian rhythm sleep disorder, a parasomnia, or as part of another mental disorder such as delirium, generalized anxiety disorder, or major depressive disorder.
Adjustment sleep disorder. Acute emotional stressors—such as bereavement, job loss, or hospitalization—can cause insomnia or daytime sleepiness. Symptoms typically remit soon after the stressors abate, so this insomnia usually lasts a few days (acute) to a few months (short-term). It can also become chronic, lasting3 months or longer.
Psychophysiologic insomnia. Once insomnia begins—regardless of its cause—sleep problems may persist well after precipitating factors resolve. The mechanism may be related to somatized tension and learned sleep-preventing associations (trying too hard to sleep and conditioned arousal to the bedroom). Thus, short-term insomnia may develop into long-term, chronic difficulty with recurring episodes or a constant, daily pattern of insomnia.
Treatment for both adjustment sleep disorder and psychophysiologic insomnia with behavioral therapies and hypnotics6 is warranted if:
- sleepiness and fatigue interfere with daytime function
- the patient is significantly distressed
- a pattern of recurring episodes develops.5
Psychiatric Disorders and Insomnia
Depression. Up to 80% of depressed persons experience insomnia, although no one sleep pattern seems typical.7 Depression may be associated with:
- difficulties in falling asleep
- interrupted nocturnal sleep
- early morning awakening.
Some patients experience panic symptoms while sleeping, possibly in association with mild hypercapnia. Those patients tend to have earlier onset of panic disorder and a higher likelihood of comorbid mood and other anxiety disorders.8
In patients with PTSD, disturbed sleep continuity and increased REM phasic activity—such as eye movements—are directly correlated with PTSD symptom severity. Nightmares and disturbed REM sleep are hallmarks of PTSD.9
Workup of Sleep Complaints
The patient history is an important part of the evaluation and treatment of insomnia and other sleep disturbances (Algorithm).12
Acute. Many short-term insomnias—lasting a few weeks or less—are caused by situational stressors, circadian rhythm changes, or poor sleep hygiene (Table 1).1 A logical approach is to begin sleep hygiene measures and explore the patient’s life situation to uncover what might be causing the insomnia. Hypnotic agents may be considered if insomnia is associated with daytime sleepiness or occupational impairment or if it seems to be escalating and your assessment indicates that it is a primary condition.
Chronic. For longer-term insomnias—lasting more than a few months—consider a more thorough evaluation, including medical and psychiatric history, physical examination, and mental status examination. A differential assessment can be made on the basis of whether a patient has difficulty falling or staying asleep (Table 1). Ask about cardinal symptoms of disorders associated with insomnia, including:
- snoring or breathing pauses during sleep (sleep apnea syndrome)
- restlessness or twitching in the lower extremities (PLMD/RLS).
Carefully review the patient’s weekday and weekend sleep patterns, bedtime habits, sleep hygiene habits, and substance and medication use.
Sleep clinic referrals. Consider an evaluation by a sleep disorders center when the diagnosis remains unclear or treatment of the presumed condition fails after a reasonable time.
Table 1
Possible causes of sleep complaints
| Acute, transient | Recent or recurring stress | |
| Change in sleeping environment | ||
| Acute illness or injury | ||
| New medications | ||
| Jet lag or shift change | ||
| Chronic | Difficulty staying asleep | Difficulty falling asleep |
| Medications | Poor sleep hygiene | |
| Drug or alcohol use | Conditioned insomnia | |
| Psychiatric disorder | Restless legs syndrome | |
| Medical disorder | Circadian rhythm disorder | |
| Sleep-disordered breathing | Advanced sleep-phase syndrome | |
| Periodic limb movement disorder | ||
| Restless legs syndrome | ||
| Source: Adapted and reprinted with permission from reference 13 | ||
Behavioral Treatments
Behavioral treatments—with or without hypnotics—are appropriate for many insomnia complaints, including adjustment sleep disorder and psychophysiologic insomnia. Behavioral measures may work more slowly than drug therapy, but their effects have been shown to last longer in patients with primary insomnia. It may be useful to start with both hypnotic and behavioral treatments and withdraw the hypnotic after behavioral measures take effect.