When people suffer from insomnia, the predominant complaint is difficulty initiating or maintaining sleep, or nonrestorative sleep, for at least 1 month.
The sleep disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning. Insomnia causes the person to feel tired and sleepy during the day. The disturbance does not occur exclusively during the course of another mental disorder (e.g., Major Depressive Disorder, Generalized Anxiety Disorder, a delirium). The disturbance is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition.