My son 17 has cp, motility problem, IS when 7 mo, hiatle hernia, has been peioitically vomiting. Symptoms are lack of apatite, pale, lethargic, then vomits 3-4 times, first time everything comes up, a lot of flym the less flym the second time. Sometime dry heaves the third n forth times, then passes out and sleeps all night. He has been on risperidol for 10 years. This just happened and typically happens at 5-6 pm every 2{ months.