Seven Mechanistically Different Classes of Medications Can Be Used to Treat Insomnia and Related Sleep Disorders.

This column reviews the neurobiology of the sleep-wake cycle as it is currently known, the 7 classes of currently available sleep-enhancing medications, and how their mechanisms of action relate to the neurobiology of sleep. Clinicians can use this information to select medications for their patients, which is particularly important because some patients respond to some of these medications but not others, or tolerate some but not others. This knowledge can also help the clinician switch among classes when a medication that was initially efficacious begins to fail a patient. It can also prevent the clinician from cycling through all of the members of a single medication class. Such a strategy is unlikely to be helpful for a patient except in the situation in which pharmacokinetic differences among members of the medication class result in some agents in that class being helpful for a patient who has either a delayed onset of action or undesirable carry-over effects with other agents in that class. An understanding of the classes of sleep-enhancing medications highlights the importance of knowing the neurobiology that underlies a psychiatric illness. The activity of a number of neurobiological circuits, such as the one reviewed in this column, has now been well established, while work to understand others is still at a much earlier stage. Psychiatrists who gain an understanding of such circuits will be better able to provide effective care for their patients.