I just wanted to mention that long term use of melatonin in children doesn't have much research. Melatonin does affect other hormones and biochemical reactions in the brain. Daily use is considered only under medical direction, although it is a "natural product". We have used it a dozen times or so. Mostly to get back to sleep if we have a hugely busy day ahead, and ds awakens at 2am, unable to resettle. Our experience giving it at bedtime was that it helped him *get* to sleep, but not keep him asleep. Apparently, some children diagnosed with ADHD and autism do not produce adequate amounts and need supplementation routinely, generally in much larger doses than over-the-counter recommendations.
Getting physical activity in bright sunlight; and then turning the lights down early in the evening has helped regulate his sleep naturally also, it seems. Eliminating wheat and dairy helped the most. (oh, and the Feingold diet).
Melatonin usage, from Medline:http://www.nlm.nih.gov/medlineplus/d...melatonin.html
Melatonin usage, from Merck Manual: https://www.merck.com/mmhe/sec02/ch019/ch019o.html
Melatonin usage, from Mayo Clinic: http://www.mayoclinic.com/health/mel...ient-melatonin
Nutritional Melatonin, from Autism Canada Foundation: http://www.autismcanada.org/melatonin.htm
Melatonin and Children, from Medscape: http://www.medscape.com/viewarticle/448467
Systematic review of melatonin treatment in children with neurodevelopmental disabilities and sleep impairment: http://journals.cambridge.org/downlo...840b894cced959
Results of this systematic review suggest that melatonin may be effective in reducing sleep latency in children with neurodevelopmental disabilities. There is also a suggestion that the more severe the sleep disorder the more obvious the improvement. There is no evidence suggesting any benefit in total sleep time or on night-time awakenings. However, caution
is required in interpreting the findings of all three included studies because the total number of participants is very small and consequently they may be underpowered. In addition, the overall quality of evidence from the studies is limited.
Melatonin usage in Children, link with many studies: http://www.worldhealth.net/p/4187,4473.html
(Basically, there may be some benefit, but only very limited research has been done on children, over very short durations.)