If you are found to be eligible to take part in this study, you will be randomly assigned (as in the toss of a coin) to one of 2 groups. Participants in Group 1 will take melatonin daily before bedtime for 4 weeks. Patients in Group 2 will take a placebo daily before bedtime for 4 weeks. A placebo is a substance that looks like the study drug but which has no active ingredients. You will have an equal chance (50/50) of being placed in either group. Neither you nor any of the medical staff or researchers on this study will know if you are receiving the study drug or placebo.