My son, 8 years old takes Guanfacine 1/2 mg. two times a day (morning and night) to control his tics. After two weeks we noticed a huge improvment in his verbal tics. Last week, we missed his morning dose and gave him his evening dose about 2 hours late. Since that time his verbal tics have been non stop again. Is this from missing the one dose? If so how long before his tics start to subside again?