There are various forms of insomnia. Some people may experience difficulty initiating sleep while others may experience difficulty maintaining sleep. Some may report difficulty both with initiating and maintaining sleep. Insomnia is defined as difficulty in sleeping that may be acute (lasting 7 days or less), subacute (> 7 days, < one month), or chronic (one month or longer).
Insomnia is characterized by difficulty falling asleep, difficulty staying asleep, or poor quality sleep. People who suffer from insomnia often take 30 minutes or longer to fall asleep, awaken frequently throughout the night, awaken for long periods during the night, or experience “non-restorative” sleep that is not refreshing. The nighttime symptoms of insomnia may result in significant distress for the sufferer who may spend hours tossing and turning in bed.
Insomnia is associated with impairments in daytime functioning. People with insomnia commonly report daytime fatigue or daytime sleepiness that interferes with their lives. Symptoms can be so severe that the insomnia sufferer cannot engage in productive activity, or finds that temporary relief comes only after retreating to a quiet place to nap.
Sleepless nights commonly take their toll in family, social, and work settings. People with insomnia say that they have more difficulties dealing with minor stress, and more problems relating to others in social and work settings, than those without insomnia. One study has shown that the “quality of life” of people with insomnia is markedly poorer than people who do not have sleep difficulties.
The problems associated with insomnia have a real impact on daytime performance. People with insomnia report greater impairment in mental functioning than healthy sleepers, including problems with attention, concentration, and memory. They also are at greater risk for accidents or injuries due to fatigue. Research data have shown that people with insomnia are 2.5 times more likely to be involved in a fatigue-related motor vehicle accident than healthy sleepers, and 4.5 times more likely to be involved in an accident in the workplace than healthy sleepers.
One of the most concerning findings about insomnia is that it may be a risk factor for the development of depression. Several studies have now shown that an episode of insomnia that occurs early in life may precede the development of depressive symptoms later in life. There also may be other health consequences of insomnia, such as altered glucose metabolism or increased risk for heart disease, although studies to further examine these relationships are ongoing.
Insomnia may be a transient problem that occurs only occasionally, or it may be a more chronic condition that occurs nightly or almost every night. Approximately 36% – 56% of the adult population of the United States reports problems with occasional insomnia, while 9% – 17% report longstanding or chronic problems with their sleep. Whatever is the case, insomnia sufferers can tell when the problem is causing distress at night or interfering with daytime functioning. Even an occasional bad night can be serious when they happen at the wrong times.
What causes insomnia? There are multiple factors that contribute to the occurrence or maintenance of insomnia. These factors include stress, medical conditions (e.g., pain, arthritis), psychiatric conditions (e.g., depression), medications (e.g., stimulants, beta-blockers, and some antidepressants), the use of alcohol and drugs, or environmental conditions. Insomnia also may be due to underlying sleep disorders such as sleep apnea, restless legs, or periodic limb movement disorder. Identifying the underlying cause of one’s insomnia can be important to finding relief, and can genuinely help to guide medical treatments. However, not all people with insomnia can easily identify an underlying cause.