Long-Term Efficacy and Safety of Ramelteon in Adults With Chronic Insomnia.

Inclusion Criteria * Females of childbearing potential who are sexually active must agree to use adequate contraception, and can neither be pregnant nor lactating from Screening throughout the duration of the study. * Body mass index between 18 and 34, inclusive. * Based on sleep history, has had chronic insomnia for at least 3 months. * Based on sleep history, reports a subjective sleep latency greater than or equal to 45 min and a subjective total sleep time less than or equal to 6.5 hours. * Based on sleep history, habitual bedtime is between 10:00 PM and 1:00 AM. * Mean latency to persistent sleep of greater than 20 minutes on two consecutive screening nights with neither night less than 15 minutes. Also, a mean of 60 minutes of wake time during the 480 minutes in bed across two nights with no night less than 45 minutes. * Based on sleep history, normally uses pharmacological assistance to sleep 0 to 4 times per week in the last 3 months. Exclusion Criteria * Known hypersensitivity to ramelteon or related compounds, including melatonin, and melatonin related compounds. * Participated in any other investigational study and/or taken any investigational drug within 30 days or five half-lives prior to the first dose of single-blind study medication, whichever is longer. * Sleep schedule changes required by employment (eg, shift worker) within three months prior to the administration of single-blind study medication. * Flown across greater than three time zones within 7 days prior to or during screening. * Participated in a weight loss program or has substantially altered their exercise routine within 30 days prior to the administration of single-blind study medication. * Has ever had a history of seizures, sleep apnea, restless leg syndrome, periodic leg movement syndrome, chronic obstructive pulmonary disease or fibromyalgia. * History of psychiatric disorder within the past 6 months. * History of alcohol abuse within the past 12 months, as defined in Diagnostic \& Statistical Manual of Mental Disorders, 4th Edition Revised, or regularly consumes more than 14 alcoholic drinks per week, or consumed any alcoholic drinks within 24 hours of any polysomnogram visits. * History of drug abuse within the past 12 months, as defined in Diagnostic \& Statistical Manual of Mental Disorders, 4th Edition Revised. * Current significant hepatic, renal, endocrine, cardiovascular, gastrointestinal, pulmonary, hematologic, neurological, or metabolic disease, unless currently controlled and stable with protocol-allowed medication, within 30 days prior to the first night of single-blind study medication. * Apnea hypopnea index (per hour of sleep) greater than 10 as seen on the first polysomnogram screening night. * Periodic Leg Movement Syndrome with arousal index (per hour of sleep) greater than 10 as seen on the first polysomnogram screening night. * Positive urine drug screen at Screening Visit 1 or any of the polysomnogram assessment visits. * Positive breathalyzer test on any of the polysomnogram assessment visits. * Uses tobacco products (including nicotine gum and patch) or any other products that may interfere with the sleep wake cycle during nightly awakenings. * Used any central nervous system medication or other drugs or supplements known to affect sleep/wake function within 1 week (or 5 half lives of the drug, whichever is longer) prior to the administration of single-blind study medication. These medications must not have been used to treat psychiatric disorders. * Intends to continue taking any disallowed medication or any prescription medication or over the counter medication that is known to affect the sleep/wake function or otherwise interfere with evaluation of the study medication. The subject must report all prescription and over the counter medications taken in the three weeks prior to screening. * Is required to take or continues taking any disallowed medication, prescription medication, herbal treatment or over-the counter medication that may interfere with evaluation of the study medication, including: * Anxiolytics * Sedatives * Hypnotics * CNS active drugs (including herbal) * Antidepressants * Narcotic analgesics * Anticonvulsants * Beta blockers * Sedating H1 antihistamines * St. John's Wort * Systemic steroids * Kava-kava * Respiratory stimulants * Ginkgo-biloba * Decongestants * Over-the-counter and prescription stimulants * Antipsychotics * Over-the-counter and prescription diet aids * Muscle Relaxants * Melatonin and all other drugs or supplements known to affect sleep/wake function * Any additional condition(s) that in the Investigator's opinion would * affect sleep/wake function * prohibit the subject from completing the study * indicate that continuation in the study would not be in the best interests of the subject. * History of hepatitis B or hepatitis C.