AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Background

Primary insomnia is sleeplessness that is not attributable to a medical, psychiatric, or environmental cause. The diagnostic criteria for primary insomnia (307.42) from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) are as follows:

• The predominant symptom is difficulty initiating or maintaining sleep, or nonrestorative sleep, for at least 1 month.
• The sleep disturbance (or associated daytime fatigue) causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.
• The sleep disturbance does not occur exclusively during the course of narcolepsy, breathing-related sleep disorder, circadian rhythm sleep disorder, or a parasomnia.
• The disturbance does not occur exclusively during the course of another mental disorder (eg, major depressive disorder, generalized anxiety disorder, a delirium).
• The disturbance is not due to the direct physiological effects of a substance (eg, drug abuse, medication) or a general medical condition.

The International Classification of Sleep Disorders does not recognize a category of primary insomnia but discusses the following 3 free-standing insomnia subgroups:

• Psychophysiological insomnia
• Idiopathic insomnia
• Sleep state misperception

The disorder is chronic by definition (ie, lasting at least 1 mo).

Pathophysiology

Psychophysiological insomnia

The synonyms are learned insomnia or behavioral insomnia, when persistent.

The primary components involved are intermittent periods of stress, which result in poor sleep and generate 2 maladaptive behaviors, including (1) a vicious cycle of trying harder to sleep and becoming tenser, expressed by patients as "trying too hard to sleep," and (2) bedroom habits and routines and other sleep-related activities (eg, brushing teeth), conditioning the patient to frustration and arousal.

Bad sleep habits such as those naturally acquired during periods of stress are occasionally reinforced and, therefore, are not resolved and become persistent. Thus, the insomnia continues for years after the stress has abated and is labeled persistent psychophysiological insomnia.

Idiopathic insomnia

Lifelong sleeplessness is attributed to an abnormality in the neurologic control of the sleep-wake cycle involving many areas of the reticular activating system (promoting wakefulness) as well as in areas such as solitary nuclei, raphe nuclei, and medial forebrain area (promoting sleep).

Possibly, a so-called neuroanatomic, neurophysiologic, or neurochemical lesion exists in the sleep system in which patients tend to be on the extreme end of the spectrum toward arousal.

Sleep state misperception

The patient reports experiencing insomnia without objective evidence of any sleep disturbance.

Frequency

United States

Primary insomnia is diagnosed in approximately 15% of patients with insomnia who are referred to sleep disorder centers following exclusion of other predisposing conditions. However, true incidence is not known. Primary insomnia is estimated to occur in 25% of all patients with chronic insomnia.

Mortality/Morbidity

Whether the consequences associated with chronic insomnia outweigh the costs of treatment remains debatable. Despite that, the following associations have been noted:

• Increased risk of mortality is associated with short sleep lengths.
• Insomnia is the best predictor of the future development of depression.
• Catastrophic worry about the consequences of not sleeping is common among patients with chronic insomnia and serves to maintain the sleep disturbance.
• Increased risk exists of developing anxiety, alcohol and drug use disorders, and nicotine dependence.
• Poor health and decreased activity occur.
• Onset of insomnia in older patients is related to decreased survival.

Sex

Primary insomnia is more common in women than in men.

Age

Persons of any age may be affected, although primary insomnia is more common in the older population.

CLINICAL

Section 3 of 11  

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• Clinical
• Differentials
• Workup
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• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

History

A thorough clinical interview with the patient and his or her sleep partner is critical in making the correct diagnosis of primary insomnia.

• Psychophysiological insomnia
• • Sleep disturbance varies from mild to severe.
  • Insomnia may manifest as difficulty falling asleep or as frequent nocturnal awakenings.
  • Patients often find that they can sleep well anywhere else but in their own bedroom (see Pathophysiology).
  • Patients with this type of insomnia tend to be more tense and dissatisfied compared to people who sleep well. Emotionally, they typically are repressors, denying problems.
• Idiopathic insomnia
• • Insomnia is long-standing, typically beginning in early childhood.
  • Patients often present with other hard-to-localize neurologic signs and symptoms such as difficulties with attention or concentration, hyperactivity, and mild nonfocal electroencephalographic abnormalities.
  • Emotionally, persons with childhood-onset insomnia are often repressors, denying and minimizing emotional problems.
  • These individuals often show atypical reactions, such as hypersensitivity or insensitivity, to medications.
  • Insomnia tends to persist over the entire life span and can be aggravated by stress or tension.
• Sleep state misperception: Patients report insomnia subjectively, while sleep duration and quality are completely normal.

Physical

No obvious physical findings are present other than possible signs of sleep deprivation and fatigue such as eye redness.

• Mental status; drowsiness; and mood changes such as irritability, anxiety, and sad feelings from underlying depression may be noted. The clinician should also note the patient's orientation, memory, judgment, insight, and the presence of any hallucinations or delusions.
• As with any mental status (but especially with the concern about depression), assess the patient's suicide potential. For completeness, assess the patient's homicidal potential as well.

Causes

Exclusion of other common causes is required to make the diagnosis of primary insomnia.

• Medical causes
• • Chronic pain, especially neuropathic pain
  • Primary sleep disorders (eg, sleep apnea, periodic limb movements, restless legs syndrome)
  • Dyspnea from any cause
  • Pregnancy
  • Drug use or withdrawal (eg, selective serotonin reuptake inhibitors, stimulants, antihistamines, caffeine, diet pills, herbal preparations containing ma huang, anticonvulsants, steroids)
• Psychiatric and/or psychological causes
• • Mood disorders (eg, depression, mania): Recent findings have strengthened the evidence that primary insomnia may be linked with mood disorders and is associated with hypothalamic-pituitary-adrenal (HPA) axis overactivity and excess secretion of corticotropin-releasing factor (CRF), adrenocorticotropin-releasing hormone, and cortisol.
  • Anxiety disorders (eg, generalized anxiety, panic attacks, obsessive–compulsive disorder)
  • Substance abuse (eg, alcohol or sedative/hypnotic withdrawal)
  • Major life stressors and/or events
• Environmental causes
• • Noise
  • Jet lag or shift work
  • Bedroom too hot or cold

DIFFERENTIALS

Section 4 of 11  

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• Clinical
• Differentials
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• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Other Problems to be Considered

A number of occult medical, psychiatric, and substance abuse disorders can cause sleep disturbance. Also consider other sleep-related disorders, such as circadian rhythm sleep disorder and parasomnias, in the differential diagnosis. Substance abuse can cause insomnia during the intoxication phase, during the sustained use phase, and during withdrawal.

WORKUP

Section 5 of 11  

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• Medication
• Follow-up
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• Multimedia
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Lab Studies

• Laboratory studies essentially are not required for the diagnosis of primary insomnia.
• Tests required to exclude other causes of insomnia include the following:
• • Thyroid function tests (hyperthyroidism)
  • Blood alcohol levels (alcohol-related psychosis)

Imaging Studies

• Neuroimaging studies may be helpful if a structural lesion is suspected to cause insomnia.

Other Tests

• Sleep diary (see Media file 1)
• • This is a questionnaire completed by the patient each morning to describe the previous night's sleep.
  • Data from the sleep diary may help minimize distortions in sleep information recalled in the physician's office.
• Actigraphy: This is a recently developed technique that makes use of an activity monitor to record activities during sleep and waking. It is useful in the diagnosis of circadian rhythm sleep disorders, sleep state misperception, and other types of primary insomnia. In older adults treated for chronic primary insomnia, the clinical use of actigraphy is still suboptimal in detecting wakefulness.

Procedures

• Polysomnography: This is not recommended for routine evaluation of insomnia but may be used in special circumstances (eg, exclusion of primary sleep disorders).
• Multiple sleep latency test
• • Psychophysiological insomnia and idiopathic insomnia manifest as increased sleep latency, reduced sleep efficiency, and increased number and duration of awakenings.
  • Sleep state misperception manifests as normal sleep latency (15-20 min), normal number of arousals and awakenings, and normal sleep duration (6.5 h). The multiple sleep latency test shows normal daytime vigilance. Sleep state misperception can be diagnosed only in the laboratory because of the need to document that sleep duration and quality are normal when a person claims to have poor sleep.

TREATMENT

Section 6 of 11  

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• Introduction
• Clinical
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• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Medical Care

Pharmacologic treatment usually provides rapid symptom relief, but controlled studies of long-term treatment have not been conducted.

• Nonprescription drugs
• • The active agent in many of these over-the-counter medications is one of the sedating antihistamines. They are generally safe but have anticholinergic adverse effects such as dry mouth, blurred vision, urinary retention, and confusion in older patients, which can be potentially more serious in patients with dental caries, glaucoma, prostatic enlargement, and dementia (or delirium), respectively.
  • They are also minimally effective in inducing sleep and may reduce sleep quality. Consequently, discourage patients from using them on a routine basis.
  • Discourage the use of various herbal preparations (eg, herbal tea) and so-called nutritional substances because of the lack of evidence in their support.
  • Studies have shown that melatonin may be useful for short-term adaptation to jet lag or other circadian rhythm sleep disorders. A recent study showed that ramelteon, a highly selective agonist for melatonin subtypes 1 and 2 receptors, is a good option for the treatment of insomnia characterized by difficulty falling asleep. In patients with insomnia, treatment with ramelteon was generally well tolerated and resulted in modest but statistically significant decreases in the latent period for sleep.¹ Ramelteon is the first FDA-approved melatonin receptor agonist drug.
• Prescription drugs
• • Hypnotics and benzodiazepines (BZDs) are the mainstays of short-term treatment of primary insomnia.
  • Basic principles for rational treatment of insomnia are to use the lowest effective dose, to use intermittent dosing (2-3 nights per wk), to use for short term (2-3 wk at a time), to discontinue after slow taper if the patient has been taking it regularly, and to use agents with short and/or intermediate half-life to minimize daytime sedation.
  • Pharmacokinetic properties and risk-benefit ratio are the key factors in selecting the most appropriate medication.

    Table. Commonly Used Hypnotics

    Duration	Agent	Dose	Half-Life	Peak Action
    Long acting	Flurazepam	15-30 mg	48-120 h	0.5-1 h
    	Quazepam	7.5-15 mg	41 h	2 h
    Intermediate acting	Estazolam	1-2 mg	10-24 h	2 h
    	Temazepam	7.5-30 mg	3.5-18 h	1.2-1.6 h
    	Lorazepam	0.5-2 g	10-20 h	2-4 h
    	Oxazepam	10-15 mg	5-20 h	3 h
    Short acting	Triazolam	0.125-0.5 mg	1.5-5.5 h	1-2 h
    	Zolpidem*	5-10 mg	2.5 h	1.6 h
    	Zaleplon†	5-10 mg	0.9-1 h	0.9-1.5 h

    *Zolpidem (Ambien) is in the class of imidazopyridines, structurally unrelated to BZDs.
    †Zaleplon (Sonata) is in the class of pyrazolopyrimidines, also structurally unrelated to BZD.
  • Common adverse effects of hypnotics are as follows:
  • • Anterograde amnesia and withdrawal effects may occur, especially with short-acting BZD (not with zolpidem and zaleplon).
    • Residual daytime sedation with intermediate-acting and long-acting drugs may occur, depending on dosage and half-life.
    • Rebound insomnia may occur with short-acting and intermediate-acting BZD after discontinuation.
    • Dosage, pharmacokinetic properties, and risk-benefit ratio are the key factors in selecting the most appropriate medication.
    • Short-acting agents are recommended for patients with difficulty falling asleep, while intermediate-acting drugs are indicated for problems with sleep maintenance.
    • Avoid long-acting agents, especially in older people, because they cause daytime sedation, impair cognition, and thereby increase the risk of falls.
  • Contraindications of these agents are as follows:
  • • Pregnancy is a contraindication.
    • Untreated obstructive sleep apnea is a contraindication.
    • History of substance abuse is a contraindication.
    • Caution and close monitoring is needed in older people and in patients with hepatic, renal, or pulmonary disease.
  • Antidepressants are indicated for use in patients with insomnia associated with psychiatric disorders or patients who have a previous history of substance abuse. Sedating antidepressants, such as trazodone and nefazodone, are sometimes used at bedtime in small doses (50 mg). They are not associated with tolerance or withdrawal and do not have anticholinergic adverse effects. SSRIs like paroxetine are found to be ineffective for treating primary insomnia in old age. Like other antidepressants, little scientific evidence supports their efficacy in the treatment of insomnia without associated depression.
• Nonpharmacologic treatment: Psychological treatment for insomnia consists primarily of patient education and short-term cognitive-behavioral therapies. The focus is primarily on sleep hygiene or factors presumed to perpetuate insomnia; as such, these therapies seek to modify maladaptive sleep habits and to educate patients about healthier sleep practices.
• • Stimulus control therapy: The purpose is to reestablish the connection between the bed and sleep by prohibiting the patient from engaging in nonsleep activities while in bed. The instructions given to the patient are (1) to go to bed only when sleepy, (2) to use the bed and bedroom only for sleep and intimacy, (3) to avoid trying to force sleep (go into another room whenever unable to fall asleep within 20-30 min and return to bed only when sleepy again), (4) to get up at the same time each morning regardless of how much the patient slept the previous night, and (5) to avoid daytime napping.
  • Sleep restriction therapy: This involves limiting the amount of time the patient spends in bed to the actual amount of time the patient usually spends sleeping. This results in sleep deprivation, which accumulates and causes more rapid sleep onset on subsequent nights. As sleep improves, the patient is allowed to gradually increase time in bed by 15-30 minutes.
  • Relaxation therapies: Relaxation-based interventions are indicated based on the observation that patients with insomnia often display high levels of arousal (physiologic and cognitive) both at night and during the daytime. The various techniques available to deactivate the arousal system are (1) progressive muscle relaxation, (2) biofeedback, and (3) imagery training and thought stopping.
  • Cognitive behavior therapy: This consists of identifying patient-specific dysfunctional sleep cognitions, challenging their validity, and replacing them with more adaptive substitutes such as reattribution training, reappraisal, and attention shifting. A recent randomized clinical trial determined that 4 individual, biweekly sessions represent the optimal dosing for cognitive behavioral intervention.²
• • Paradoxical intention: This method consists of persuading a patient to engage in his or her most feared behavior (ie, staying awake). This serves to eliminate performance anxiety so that sleep may come more easily.

Consultations

Consultation with a sleep disorders specialist may be necessary if the standard pharmacologic and behavioral treatments are not effective.

MEDICATION

Section 7 of 11  

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• Follow-up
• Miscellaneous
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• References

The goals of pharmacotherapy are to reduce morbidity and to prevent complications. In addition to the FDA-approved drugs listed below, new experimental drugs are being developed. Among them is indiplon, which is a unique nonbenzodiazepine experimental drug that acts on a specific site of the gamma-aminobutyric acid (GABA)-A receptor. Initial studies have shown significantly improved subjective measures of sleep induction and maintenance in elderly women with chronic insomnia at a dose of 5-10 mg.³ Gaboxadol is another experimental drug that is a direct-acting GABA-A agonist. It has now entered phase III development for the treatment of insomnia following promising results from phase II trials. An initial trial showed improvement in sleep maintenance and total sleep time.⁴

Drug Category: Benzodiazepine hypnotics

The primary indication is for short-term management of insomnia, either as the sole treatment modality or as adjunctive therapy until the underlying problem is controlled. Hypnotics can be useful in psychophysiological insomnia for particularly poor nights or when the subjects know ahead of time that they will encounter difficulty sleeping (eg, before an examination or a presentation). An occasional hypnotic can be used for sleep state misperception when the patient becomes extremely worried about perceived lack of sleep for several nights.

Drug Category: Nonbenzodiazepine hypnotics

These agents are gaining popularity because they do not have significant effect on sleep architecture and are not associated with the rebound phenomenon seen with the benzodiazepines.

Drug Category: Antidepressants

Indicated for use when insomnia is associated with psychiatric disorders or if the patient has a history of substance abuse. As with other antidepressants, little scientific evidence supports efficacy in the treatment of insomnia without associated depression.

Drug Category: Melatonin agonists

Indicated for insomnia characterized by difficulty with sleep onset.

FOLLOW-UP

Section 8 of 11  

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• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Further Inpatient Care

Inpatient care is not usually required unless significant medical or psychiatric comorbidity exists.

Further Outpatient Care

Effective treatment for insomnia consists of a dual approach using nonpharmacologic techniques and appropriate use of hypnotic agents.

Deterrence/Prevention

Proper attention to sleep hygiene may prevent the development of psychophysiological insomnia.

Complications

Sleep disturbance is a reliable indicator of psychological ill health, physical ill health, or both. A report of disturbed sleep from the patient signals the need for further evaluation and close monitoring.

Prognosis

In some patients, improvement in sleep leads to an improved quality of life.

Patient Education

• The following sleep hygiene recommendations that include environmental and lifestyle modifications should be used as an adjunct to other forms of therapy.
• • Eliminate the use of caffeine, especially after noon.
  • Do not use tobacco or alcohol near bedtime.
  • Avoid heavy meals close to bedtime (may eat a light snack at bedtime).
  • Exercise early in the day before dinner to alleviate stress, but do not exercise before bedtime.
  • Avoid daytime naps, and establish a regular schedule for going to bed and getting up.
  • Keep the bedroom at a comfortable temperature, and minimize light and noise.

• Family education and patient self-help information are also important. Resources on sleep disorders can be found at the National Sleep Foundation Web site. For education on various disorders, patients can be directed to the Web sites of the Patient Education Institute, NIH Senior Health, and the United States Department of Health and Human Services.
• For excellent patient education resources, visit eMedicine's Mental Health and Behavior Center and Sleep Disorders Center. Also, see eMedicine's patient education articles Primary Insomnia, Insomnia, Disorders That Disrupt Sleep (Parasomnias), Understanding Insomnia Medications, Sleep Disorders in Women, Sleep Disorders and Aging, Sleeplessness and Circadian Rhythm Disorder.

MISCELLANEOUS

Section 9 of 11  

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• Follow-up
• Miscellaneous
• Multimedia
• References

Medical/Legal Pitfalls

• Failure to diagnose

MULTIMEDIA

Section 10 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Media file 1:  Primary insomnia. Evaluation of insomnia. Format of sleep diary.
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Media type:  Image

REFERENCES

Section 11 of 11

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• References

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Article Last Updated: Feb 4, 2008