ABSTRACT
Medications affecting the neuromodulators norepinephrine, serotonin, acetylcholine, orexin, muscarine, and dopamine, often induce insomnia and/or sleepiness. Diagnoses that lead to alterations in sleep and alertness are quite common. Melatonin is a neural hormone that is effective at resetting circadian rhythms of sleep and body core temperature through its actions on the suprachiasmatic nucleus. Individuals with chronic insomnia are hyperaroused with increased corticotropin secretion throughout the sleep–wake cycle and have associated greater whole-brain metabolism. Almost all over-the-counter sleeping pills contain sedating antihistamines, usually diphenhydramine. A significant percentage of individuals with chronic insomnia and/or daytime sleepiness also have depressive symptoms. Parasomnias are sleep disorders occurring during arousal, partial arousal, or sleep state transition. Medication-induced changes in sleep and electroencephalogram activity can lead to an increase in symptoms occurring during specific sleep/dream states. A number of sleep disorders are linked to abnormally timed sleep–wake cycles.
