Careful investigation can often reveal insomnia’s cause1—whether a psychiatric or medical condition or poor sleep habits. Understanding why patients can’t sleep is key to effective therapy.
Acute and chronic sleep deprivation is associated with measurable declines in daytime performance (Box). Some data even suggest that long-term sleeplessness increases the risk of new psychiatric disorders—most notably major depression.3
PSYCHIATRIC DISORDERS AND INSOMNIA
Depression. Many depressed persons—up to 80%—experience insomnia, although no one sleep pattern seems typical.2 Depression may be associated with:
- difficulties in falling asleep
- interrupted nocturnal sleep
- and early morning awakening.
Anxiety disorders. Generalized anxiety disorder (GAD), social phobia, panic attacks, and posttraumatic stress disorder (PTSD) are all associated with disrupted sleep. Patients with GAD experience prolonged sleep latency (time needed to fall asleep after lights out) and fragmented sleep, similar to those with primary insomnia.
One-half of adult Americans experience insomnia during their lives, and 10% report persistent sleep difficulties (longer than 2 weeks). Individuals who complain of insomnia report:
- daytime drowsiness
- diminished memory and concentration
- strained relationships
- increased risk of accidents
- impaired job performance.
Despite these complaints, a surprising 70% of those with insomnia never seek medical help. Only 6% visit their physicians specifically for insomnia, and 24% address sleep difficulty as a secondary complaint. Many (40%) self-medicate with over-the-counter sleep aids or alcohol.2
Insomnia becomes more frequent with aging, associated with increased rates of medical and psychiatric illness and an age-related deterioration in the brain’s sleep-generating processes.3
Subjective sleep quality may be impaired in patients with social phobia. Some patients experience panic symptoms while sleeping, possibly in association with mild hypercapnia. Patients with sleep panic attacks tend to have earlier onset of panic disorder and a higher likelihood of comorbid mood and other anxiety disorders.4
In patients with PTSD, disturbed sleep continuity and increased REM phasic activity—such as eye movements—are directly correlated with severity of PTSD symptoms. Nightmares and disturbed REM sleep are hypothesized hallmarks of PTSD.5
Schizophrenia. Patients with schizophrenia often have disrupted sleep patterns. These include prolonged sleep latency, fragmented sleep with frequent arousals, decreased slow-wave sleep, variable REM latency, and decreased REM rebound after sleep deprivation. Despite investigations going back to the 1950s, no specific link between REM sleep and psychosis has been found.6 Interestingly, increases in REM sleep time and REM activity have been associated with an increased risk of suicide in patients with schizophrenia.7
Adjustment sleep disorder. Acute emotional stressors—such as bereavement, job loss, or hospitalization—often cause adjustment sleep disorder. Symptoms typically remit soon after the stressors abate, so this transient insomnia usually lasts a few days to a few weeks. Treatment with behavioral therapies and hypnotics8 is warranted if:
- sleepiness and fatigue interfere with daytime functioning
- a pattern of recurring episodes develops.9
Psychophysiologic insomnia. Once initiated—regardless of cause—insomnia may persist well after its precipitating factors resolve. Thus, short-term insomnia may develop into long-term, chronic difficulty with recurring episodes or a constant, daily pattern of insomnia. Sufferers often spend hours in bed awake focused upon—and brooding over—their sleeplessness. which in turn further aggravates their insomnia.
Adjustment sleep disorder and psychophysiologic insomnia are included within DSM-IV’s term “primary insomnia.”
OTHER CAUSES OF INSOMNIA
Medications that may affect sleep quality include antidepressants (Table 1),10,11 antihypertensives, antineoplastic agents, bronchodilators, stimulants, corticosteroids, decongestants, diuretics, histamine-2 receptor blockers, and smoking cessation aids.
Recreational drugs, such as cocaine, often cause insomnia. Hypnotics and anxiolytics can cause insomnia following long-term use and during withdrawal.
Other disorders known to disturb sleep include periodic limb movement disorder (PLMD), restless legs syndrome (RLS), sleep apnea syndrome, disrupted circadian rhythms (as with travel or shift work), cardiopulmonary disorders, chronic pain, diabetes, hyperthyroidism, hot flashes associated with menopause, seizures, dementia, and Parkinson’s disease, to name a few.
WORKUP OF SLEEP COMPLAINTS
Acute. Most short-term insomnias—lasting a few weeks or less—are caused by situational stressors, circadian rhythm alterations, and sleep hygiene violations. A logical initial approach, therefore, is to combine sleep hygiene measures with supportive psychotherapy. Hypnotic agents may be considered for apparent daytime consequences—such as sleepiness and occupational impairment—or if the insomnia seems to be escalating.
Chronic. For longer-term insomnias—lasting more than a few weeks—consider a more thorough evaluation, including medical and psychiatric history, physical examination, and mental status examination. Inquire 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 (PLMS/RLS).
Question the bed partner, who may be more aware of such symptoms than the patient. Carefully review sleep patterns on weekdays and weekends, bedtime habits, sleep hygiene habits, and substance and medication use.