insomnia

insomnia, the inability to sleep adequately. Causes may include poor sleeping conditions, circulatory or brain disorders, a respiratory disorder known as apnea, stress, or other physical or mental disorders. Insomnia is not harmful if it is only occasional; the body is readily restored by a few hours of extra sleep. If, however, it is regular or frequent, insomnia may have harmful effects on other systems and functions of the body. Treatment of mild insomnia may...