Internalized anger and anxiety are the most common reasons for insomnia. Depression may also trigger some forms of insomnia, such as waking too early.
Behavioral factors can also lead to insomnia.
Chronic insomnia, by contrast, is usually caused by depression. Physical ailments, such as kidney disease, heart failure, asthma, arthritis, Parkinson's disease or hyperthyroidism, may work with emotional factors to produce chronic insomnia. Other sleep disorders may also lead to chronic insomnia, including sleep apnea, narcolepsy and restless legs syndrome. Individuals at risk for increased insomnia are the elderly, women and those with a history of depression. Women may be more likely to get insomnia because of their menstrual cycles.