A 48-year-old woman is reporting difficulty sustaining sleep without interruptions. She is currently taking over-the-counter melatonin, and she denies difficulty with sleep onset. Because her middle insomnia has persisted for 3 months and is nonspecific to a trigger, she has decided to address her insomnia with psychotropics. Which of the following is true of melatonin? a. Melatonin is a synthetic psychotropic with dose-dependent side effects b. Melatonin should be taken at the same time every night c. Melatonin should be taken 4 hours before going to bed for every patient, as randomized controlled trials indicate efficacy for this time interval d. Melatonin should be taken as needed, and only when sleep onset is elusive