I have mentioned this here before. My husband started "sun downing", wandering off in the middle of the night. I live on 22 acres out in the woods.(an elderly neighbor disappeared when she got up at night and was never found) One morning I woke up to find him missing. I found him 1/4 of a mile from our house where he had fallen and was laying face down in the dirt. He had hypothermia and the ambulance took him to the emergency room.
I started giving him 10 mg of melatonin at 4 pm and another 10 mg of melatonin at 9pm. He never sun downed again except for one time when my son didn't give him the first dose until 6pm.
Yesterday I read that it is believed that melatonin can help prevent strokes. I don't think there are many problems with it except drowsiness.