ABSTRACT
INTRODUCTION Insomnia is commonly defined as repeated difficulty with either initially falling asleep (sleep onset insomnia) or remaining asleep (sleep maintenance insomnia). This occurs despite adequate opportunity, condition, and time for sleep to occur and is associated with impairment of daytime function. Patients with insomnia may describe frequent extended periods of wakefulness during the sleep period or persistent morning awakenings that are earlier than desired (terminal insomnia). Insomnia can be divided on the basis of its duration into transient or short-term (lasting only a few days to three to four weeks) or chronic (persisting for more than one to three months). This chapter on pharmacologic therapy of sleep disturbance will be limited to the treatment of chronic insomnia.
