I strongly recommend trying melatonin ONLY if you have a week free to see if it works. Tried it with my kid, and it caused major depression. We took her off it, and the depression lifted after a few days. We tried it again, for ONE DAY, and she melted down the next day for another WEEK. And this was the lowest dosage we could find! No more melatonin here!

Anything that meddles with brain chemistry should be tried only if one is A: really really desperate, or B: in possession of time to deal with the thing backfiring.