IRCT20090117001556N153 IRCT 2023-07-22 Department of Health, Rescue and Treatment of I.R.Iran Police Force, Applied Research Center The effect of Melatonin for sleep and function of shift workers Effects of Melatonin on Sleep Quality and Cognitive Function of Shift Workers with Sleep Disorder: A Randomized, Double-Blind, Placebo-Controlled Trial 2023-07-22 anticipated 70 Complete https://irct.ir/trial/71410 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Randomization description: Permuted block randomization using A and B blocks in a 1:1 ratio will be done with n=4: AABB, ABAB, ABBA, BABA, BAAB, BBAA The blocks were randomly used to achieve total sample size. ("A" and "B" are the study groups), Blinding description: An independent group will perform randomization, allocation concealment, and blinding procedures. The allocated group numbers will be kept confidential in sequentially numbered, sealed, and opaque envelopes to conceal treatment assignments from patients, healthcare providers, outcome assessors, and the research team. Melatonin and matched placebo are identical in size, shape, color, smell, and taste. 2-3 Sleep disorder. Intervention 1: Intervention group: Melatonin (C13H16N2O2) in the form of tablets with a dose of 5 mg produced by Jalinous Pharmaceutical Company, administered orally 30 minutes before the person's desired time to sleep at night after shift work for one month. Intervention 2: Control group: Placebo in tablet form, completely similar to the medication in terms of shape, color, smell and taste produced by Jalinous Pharmaceutical Company. Undecided - It is not yet known if there will be a plan to make this available Justification or reason for indecision in sharing IPD is The decision maker is the research center.