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.
• Has had primary chronic insomnia as defined by Diagnostic and Statistical Manual of Mental Disorders, 4th Edition Revised for at least 3 months.
• Reports a history of subjective sleep latency greater than or equal to 60 min and a subjective total sleep time less than 6.5 hours.
• Habitual bedtime is between 10:00 PM and 1:00 AM.
• Willing to have a fixed bedtime and agrees to go to bed within plus or minus 30 minutes of the habitual bedtime during the entire study.
• Consistent access to a touch tone phone and are willing to complete telephone questionnaires twice daily during participation in the study.
• Willing to remain in bed for at least 6.5 hours each night during the entire study.
• Used pharmacological assistance to sleep 0-4 times per week in the last 3 months.
• Must complete the morning questionnaire on at least 4 of the first 7 mornings after Screening Visit 1.
• On at least 3 of the first 5 nights of single-blind placebo treatment, the subject must have a subjective sleep latency of greater than or equal to 45 minutes.
• On at least 3 of the first 5 nights of single-blind placebo treatment, the subject must have a subjective total sleep time of less than 6.5 hours.

Exclusion Criteria

• Known hypersensitivity to ramelteon or related compounds, including melatonin, and 5-hydroxytryptophan.
• Participated in any other investigational study and/or took any investigational drug within 30 days prior to the first dose of single-blind study medication.
• Sleep schedule changes required by employment (eg, shift worker) within 3 months prior to the first night of single-blind study medication.
• Has flown across greater than 3 time zones within 7 days prior to screening, or will travel across 2 or more time zones during the course of the study.
• Participated in a weight loss program or has substantially altered exercise routine within 30 days prior to the first night of singleblind study medication.
• Ever had a history of seizures, sleep apnea, and/or chronic obstructive pulmonary disease.
• History of psychiatric disorder within the past 6 months.
• History of fibromyalgia.
• History of drug addiction or drug abuse within the past 12 months.
• History of alcohol abuse within the past 12 months, as defined in Diagnostic and Statistical Manual of Mental Disorders, 4th Edition Revised and/or regularly consumes more than 2 alcoholic drinks per day.
• Current significant hepatic, renal, endocrine, cardiovascular, gastrointestinal, pulmonary, hematologic, 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.
• Uses tobacco products or any other products that may interfere with the sleep wake cycle 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
  • indicate that continuation in the study would not be in the best interests of the subject.

• Is required to take or continues taking any disallowed medication, prescription medication, herbal treatment or over-the counter medication, including:

  • Anxiolytics
  • Central nervous system active drugs
  • Hypnotics
  • Narcotic analgesics
  • Antidepressants
  • Beta blockers
  • Anticonvulsants
  • St. John's Wort
  • Sedating H1 antihistamines
  • Kava-kava
  • Systemic steroids
  • Ginkgo-biloba
  • Respiratory stimulants
  • Over-the-counter and prescriptions stimulants
  • Decongestants
  • Over-the-counter and prescription diet aids
  • Antipsychotics
  • Melatonin and all other drugs or supplements known to affect sleep/wake