Advances in treating insomnia.

Too often, insomnia is treated as a symptom without investigation of the cause. Insomnia may be a condition unto itself (primary insomnia), or it may be associated with a medical or psychiatric condition (comorbid insomnia), and it may be acute or chronic. Inadequate treatment often leads to significant frustration and lost productivity. We review the classification, pathophysiology, and treatment of insomnia and discuss how we can minimize its adverse consequences.