Study of the Efficacy and Safety of NPC-15 for Sleep Disorders of Children With Neurodevelopmental Disorders

Inclusion Criteria: * Female or male patients aged 6 to 15 years. * Patients with "neurodevelopmental disorder" diagnosed by using DSM-5. * Patients with average of daily sleep latency persisted over 30 min and the condition is continuous over 3 months * Patients who are out-patient, not hospitalized patient. * Signed informed consent obtained from rearer(s)/parent(s)/guardian(s) of the patient, or signed IC or informed assent obtained from the patient themselves. Exclusion Criteria: * Patients with at least severity in either Conceptual area, or Social area, or Practical area of intellectual disability have judged more than " the most severe" by using DSM-5. * Patients who took melatonin (including supplement) in history. * Patients who had taken Ramelteon within 4 weeks before clinical study starts.