When you're lying awake, with a dismal headache, and repose is tabooed by anxiety; I conceive you may use any language you choose to indulge in, without impropriety.
Thus begins the Lord Chancellor's patter song in the Gilbert and Sullivan operetta Iolanthe. The Lord Chancellor is suffering insomnia because of "love unrequited," but the condition he describes in the song, including bizarre dreams, unrestful sleep, sore eyes, and fitful wakings, is a litany of signs and symptoms encountered by many patients who suffer from either transient or chronic insomnia.
Incidence, characteristics, and potential harm
Most studies indicate that approximately one-third of the population suffers from occasional difficulty in sleeping, with estimates approaching 50%, according to some epidemiologic reports. Chronic sleep difficulties affect approximately 20% of the population. While insomnia tends to be worse in women, sleep difficulties increase with age in both genders. However, these generalizations must be qualified, since patient perception of sleep is often skewed. Typically, patients overestimate the time required for onset of sleep and underestimate the number of nighttime awakenings, as compared with polysomnographic assessment of sleep behavior. Since insomnia is often classified as (1) trouble falling asleep, (2) frequent awakenings after falling asleep, or (3) early awakenings with an inability to resume sleep, these subjective perceptions are important in choosing appropriate therapy
Insomnia can be classified as either acute or chronic and as either primary or secondary Either acute or chronic insomnia may be secondary to some other causative situation. Acute or transient insomnia often results from sudden changes in daily routine or a sudden stress in the life of the patient. Examples of these may include sudden shifts in time zone (i.e., jet lag), personal conflicts (such as spousal/marital difficulties, financial worries, a death in the family), and abnormal eating, drinking, or exercise behaviors. Chronic insomnia may be secondary to a diagnosable psychiatric disease, such as depression or psychosis, or to substance abuse and addiction (including both alcohol and nicotine). Additionally, continued lifestyles such as large evening meals (especially within two to four hours of bedtime), evening exercise within the same time frame, or excessive television watching or reading in bed immediately prior to sleep may cause sleep difficulties. Either transient or chronic insomnia may also be secondary to a preexisting medical condition, including arthritis, peptic ulcer disease, cardiovascular disease, any of the chronic obstructive pulmonary diseases, numerous psychiatric conditions (OCD, depression, anxiety, and panic disorders), and sleep apnea. Additionally, there are very strong correlations between insomnia and Norrie disease, Prader-Willi syndrome, and Moebius syndrome-three rare hereditary diseases that specifically affect distinct chromosomes and cause localized CNS lesions.
Drug therapy may also be a major cause of secondary insomnia, with many drug classes possessing the ability to interfere with sleep. This list includes, but is certainly not limited to, any CNS stimulant (including over-the-counter decongestants and caffeine), diuretics (by increased need to void during the night), corticosteroids, antihypertensives, and antidepressants. Both SSRI and tricyclic antidepressants may disturb normal sleep patterns. Many of the drugs that alter sleep may do so while possessing sedation as a major side effect (i.e., antihistaminics and anticholinergics). This is often attributed to their ability to interfere with the sleep cycle, reducing stage 3 and 4 sleep and therefore causing a loss of "restful" or restorative sleep.
Primary insomnia is reportedly less common than secondary cases of sleep disorders. The Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) classifies primary insomnia as difficulty falling asleep or maintaining sleep, or unrestful sleep that persists for at least one month and is not attributable to any exogenous factors, as described above. …