Melatonin is even more effective at causing crazy, vivid dreams. Sometimes I go straight into dreaming as soon as I fall asleep. I can only take it 1 or 2 nights at a time before that starts happening, and then I have to discontinue use. Melatonin is further down in the serotonin biosynthesis pathway, http://www.ch.ic.ac.uk/local/projects/s_thipayang/synthesis.gif