My grand daughter is 5 years 1/2 old. We are concerned that she has a chemical imbalance. Since she was very young, 2, she has often gone without sleeping for a period of 30 hours and then will only sleep 6 hours. She often wakes at night at about 2 or 3 pm and will stay awake past bed time the next night. During these times if she naps it will be for only an hour or 2 and then is up and running around again. Her pediatrician has prescribed malatonin which is beginning to stop working. She is a twin and the youngest of 5. Her twin is a boy, her older siblings are another set of twins, 12 years old and a brother 15. She is given the same discipline as her siblings but she seems to have behavior problems. She will go from a good and well behaved child to intensely angry in a matter of minutes, where she will harm her siblings in retaliation for a punishment or when they don t do what she wishes, also acting out for attention and laughing about the naughty behavior when given punishment. She will then just as suddenly become the perfect child again. When she is in these mood swings discipline doesn t seem to work. Concerning discipline, we have tried a sticker chart, rewards when she is behaved, we have deprived her of attention when naughty, corporal punishment doesn t work and she laughs at most other forms of punishment. She also has delayed speach but is understandable. She is very coordinated, intelligent, inquisitive. Is it possible that she does have a chemical imbalance or some other condition? Is this a mental health issue?