Efficacy of Ramelteon in Subjects With Chronic Insomnia

Inclusion Criteria * Participant has participated in an allowed Ramelteon study and has completed all final visit procedures for the previous study within 21 days of the Treatment Initiation Visit for this study. * 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. * Investigator believes that participant requires long-term treatment for insomnia. * Primary insomnia as defined by the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition Revised for at least 3 months and a history of daytime complaint(s) associated with disturbed sleep. * Subjective sleep latency greater than or equal to 45 minutes and a subjective total sleep time less than or equal to 6.5 hours per night for at least 3 nights during the week of the Baseline Lead-in Period. * Habitual bedtime is between 8:30PM and 12:00AM. * Body mass index between 18 and 34, inclusive. Exclusion Criteria * Known hypersensitivity to Ramelteon or related compounds, including melatonin. * Participated in any other investigational study, and/or taken any investigational drug within 30 days or five half-lives prior to Day 1 of study medication, whichever is longer. The only exception to this is prior participation in an allowed Ramelteon study. * Sleep schedule changes required by employment (eg, shift worker) within three months prior to Day 1 of study medication, or has flown across greater than three time zones within seven days prior to screening. * Participated in a weight loss program or has substantially altered their exercise routine within 30 days prior to Day 1 of study medication. * Ever had a history of seizures, sleep apnea, chronic obstructive pulmonary disease, restless leg syndrome, schizophrenia, bipolar disorder, mental retardation, or cognitive disorder. * History of psychiatric disorder (including anxiety or depression) within the past 12 months. * History of drug addiction or drug abuse with the past 12 months. * History of alcohol abuse within the past 12 months, as defined in the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition Revised and/or regularly consumes 4 or more alcoholic drinks per day. * Current significant neurological, hepatic, renal, endocrine, cardiovascular, gastrointestinal, pulmonary, hematologic, or metabolic disease, unless currently controlled and stable with protocol-allowed medication 30 days prior to Day 1 of study medication. * Uses tobacco products during nightly awakenings. * Any clinically important abnormal finding as determined by a medical history, physical examination, electrocardiogram, or clinical laboratory tests, as determined by the investigator. * Positive hepatitis panel. * Any additional condition(s) that in the Investigator's opinion would: * affect sleep/wake function * prohibit the subject from completing the study, or * not be in the best interest of the subject to participate in the study. * Morning serum cortisol at the Baseline visit of less than 7.0 micro-g per dl. * Is required to take or continues taking any disallowed medication, prescription medication, herbal treatment or over-the counter medication, including: * Anxiolytics * Hypnotics * Antidepressants * Anticonvulsants * Sedating H1 antihistamines * Systemic steroids * Respiratory stimulants (eg, theophylline) * Decongestants * Over-the-counter and prescription stimulants * Over-the-counter and prescription diet aids * Central nervous system active drugs * Narcotic analgesics * Beta blockers * St. John's Wort * Kava-kava * Gingko biloba * Melatonin