Sleep disturbances encompass disorders of initiating and maintaining sleep (DIMS, insomnias), disorders of excessive somnolence (DOES), disorders of sleep–wake schedule, and dysfunctions associated with sleep, sleep stages, or partial arousals (parasomnias).Common causes of chronic insomnia include: Stress. Concerns about work, school, health, finances or family can keep your mind active at night, making it difficult to sleep. Stressful life events or trauma — such as the death or illness of a loved one, divorce, or a job loss — also may lead to insomnia.