My daughter has just developed tics because of a teacher who has physically attacked her at school. You have mentioned teasing, or something similar at pre-k...It will be worth checking this out as the body excretes Cortisol through the Adrenal Glands if a trauma happens. Cortisol is a flight-or-flee hormone that goes out of balance when a very stressful situation occurs like going back to school. She clearly does not sound happy at school and although I am also a beginner and not an expert at all, I shall change schools. Do not just give Magnesium because everybody else says so. It could well be an Cortisol imbalance which according to my knowledge, can only be treated by a Cortisol balancer or something like that. From another father whose daughter just developed tics because of trauma.