Sleep Disorders: Principles and Practice of Sleep Medicine - Hardcoverby Slaton Channing (Editor) Sleep medicine is a branch of medicine that is concerned with the diagnosis and treatment of sleep disorders. Sleep disorders are a group of conditions that affect the normal sleep patterns. There are various factors that can contribute to the development of sleep disorders that include age, caffeine, alcohol, and an irregular schedule. Medications, genetics and ageing also play a key role in disturbing the sleep patterns.