Could melatonin help kids with PTSD sleep better?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: Children and adolescents (2 -17.5 years) with: * A diagnosis of post-traumatic stress disorder (PTSD) as defined by DSM-5 (American Psychiatric Association, 2013) * Current significant sleep disturbances defined as ≤6 hours of continuous sleep and/or ≥0.5-hour sleep latency from lights-off on 3 out of 5 nights and/or nightmare disorder as defined by the International Classification of Sleep Disorders, Third Edition (ICSD-3, Sateia, 2014), for a minimum 3 months, based on parent report and patient medical history * No response to at least 4 weeks of sleep hygiene * Negative pregnancy test for females with childbearing potential * Written informed consent provided by both parents or a legal guardian, as well as the children / adolescents themselves, if possible * Stable doses of non-excluded medications for at least 3 months Exclusion Criteria: * Known systemic or severe acute disease whose care would hinder attendance at appointments * Pregnancy, breastfeeding * Known diagnosis of another significant sleep disorder (e.g., moderate to severe sleep apnea) * Treatment with any form of melatonin within 2 weeks prior to screening * Unresponsiveness to previous prolonged release melatonin within the 2 years prior to the study * Known allergy to melatonin or lactose * Use of prohibited medication (benzodiazepine, z-drug, antihistaminic, among others) within 2 weeks prior to screening * Start of a cognitive behavioural therapy (CBT) targeting sleep disturbances or mood disorders, within 6 weeks before study inclusion * Participation in a clinical trial within the last month prior to the study * Transmeridian travel (\> 2 time zones) within the month before the start of the study * Females not using contraceptives who are sexually active, pregnant, and/or breastfeeding * Other reasons: inability to receive clear information, inability to participate in the entire study, lack of coverage by the social security system, refusal to sign consent.