Withdrawal of Risperdal or cause of Concerta

I have a 5 year old boy who was taking 1mg of Risperdal in the morning and 1mg of Risperdal in the evening (for 8 months) to help with aggressive like behavior.  The medication was also prescibed for Asperger's like behavior to go with the aggression. The medication helped show improvement, but there was noticeable weight gain.  This led to the doctor prescribing Concerta.  After switching medicaitons, there have been several facial tics (dyskinesia like facial movements) that have occured.  While they have improved moderately, they still are occuring on day 5.  Looking to find out whether these facial tics are from the withdrawal of Risperdal or the side effects of Concerta.  Please advise.