Intrinsic sleep disorders: Insomnia

Insomnia is the complaint of difficulty initiating or maintaining sleep, combined with daytime sleepiness or impairment of daytime performance. For most patients, an occasional night fraught with difficulty falling asleep or having trouble maintaining sleep is not unusual. These occasional nights might be closely linked to the surrounding events of the day or sudden changes in medical condition. For a smaller group of patients, insomnia persisting for less than 3 months (subacute) or longer than 3 months (chronic) is a greater disruption of life and may lead to more significant medical symptoms.

The approach to the patient with insomnia should consider that multiple problems cause the lack of ability to access sleep. To sleep well, one needs to be in the correct environment, be psychologically prepared for sleep, and have the ability to access the neurophysiologic mechanisms for sleep. Most patients with chronic insomnia have factors that predispose them for insomnia, factors that initiate the insomnia, and other factors that perpetuate the insomnia. For instance, gender, age, and coping mechanisms may predispose one to insomnia, whereas poor sleep hygiene, substance abuse, and performance anxiety may perpetuate it.

Psychiatric disorders may frequently be preceded by insomnia, and the complaint of insomnia may be the last symptom to resolve with affective disorders. Patients with medical disorders such as congestive heart failure, renal failure, arthritis, and pain syndromes may complain of insomnia that is related to the medical condition. Sleep disorders such as sleep apnea, periodic limb movements of sleep, and circadian rhythm disorders also may provoke patients to complain of insomnia.

Three primary insomnia disorders have been recognized:

• Psychophysiologic insomnia, with poor sleep in the usual sleep environment but better sleep in a new environment
• Idiopathic insomnia, chronic difficulty with sleep that does not improve with change in environment and has no definable etiology
• Sleep state misperception syndrome, in which some patients perceive themselves to be awake although the physiologic parameters show that they are asleep

Physicians should take a thorough history, including a review of the patient’s 24-hour schedule; meals; caffeine, tobacco, and medicine intake; feelings about going to bed and going to sleep; and the bed partner’s report of the patient’s sleep. The patient should be asked to keep a diary of daily events, which frequently yields clues to the cause of nighttime sleep difficulties.

The approach to the epilepsy patient with insomnia is discussed separately.

Adapted from: Malow, BA, and Vaughn BV. Sleep disorders and epilepsy. In: Ettinger AB and Devinsky O, eds. Managing epilepsy and co-existing disorders. Boston: Butterworth-Heinemann; 2002;255–267.
With permission from Elsevier (www.elsevier.com).
Reviewed and revised April 2004 by Steven C. Schachter, MD, epilepsy.com Editorial Board.