Suggest Treatment For Insomnia And Severe Anxiety In A Child

My Son who is 8yo has ADHD and is currently on 36mg concerta, .5 2x a day of Risperdal and .02 clonidine at bed time - He is not sleeping and his Anxiety is THROUGH the roof. I have been researching SSRI s as i believe that he is suffering from depression / anxiety NOT a mood disorder as previously diagnosed. What is the BEST SSRI for someone my sons age that will not hurt him?