Patient description: A 25-year-old woman presents to the clinic complaining of prolonged fatigue. She denies difficulty sleeping and sleeps an average of 8 hours a night. She also notes hair loss, a change in her voice and weight gain during the previous 6 months. She complains of cold intolerance. On examination she has a prominent, soft, uniform anterior cervical mass at the midline.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Sleep Disorders, Circadian Rhythm Females of childbearing potential who is sexually active must agree to use adequate contraception from screening throughout the duration of the study Must have a diagnosis of Delayed Sleep Phase Syndrome according to International Classification of Sleep Disorders for at least 3 months Based on sleep history, subject's habitual sleep time is more than 3 hours later than the desired sleep time Must have had self reported insomnia which is defined per the sleep history as his or her sleep latency of at least 45 minutes when attempting to sleep at desired sleep time required by his or her work or school schedule The subjective sleep latency via Post sleep questionnaire during outpatient screening period must be greater than or equal to 45 minutes during every working night or school night provided the subject went to bed at their desired sleep time During single blind placebo run-in Polysomnography screening nights, subject is instructed to go to bed at their desired bed time and must demonstrate difficulty in falling asleep based on the following During Polysomnography screening nights when the subject goes to bed at their desired sleep time or The average of total wake time Is in good health as determined by a medical and psychiatric history, physical examination, Electrocardiogram, and serum chemistry and hematology Is able to complete self-rating scales via interactive voice response system, and has a touch tone phone  Has a known hypersensitivity to ramelteon or related compounds, including melatonin and melatonin-related compounds or 5-hydroxytryptophan Has participated in any other investigational study and/or taken any investigational drug within 30 days or 5 half-lives prior to the first dose of study medication, whichever is longer Has flown across greater than 3 time zones within the past 3 months prior to administration of study medication Has sleep schedule changes required by employment (eg, shift worker) within 3 months prior to the administration of study medication Has participated in a weight loss program or has substantially altered their exercise routine within 30 days prior to the administration of study medication Has a history of alcohol abuse within the past 12 months, as defined in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, or regularly consumes more than 14 alcoholic drinks per week or consumes any alcoholic drinks within 24 hours of Screening Visit Has a history of drug abuse within the past 12 months Has a current, clinically significant neurological (including cognitive), hepatic, renal, endocrine, cardiovascular, gastrointestinal, pulmonary, hematological, or metabolic disease, as determined by the investigator Has a probable current diagnosis of another circadian rhythm disorder or a sleep disorder other than Delayed Sleep Phase Syndrome that is the primary cause of insomnia Had an apnea hypopnea index greater than 10 on the first night of Polysomnography Screening