Has anyone experienced manic and or psychotic behavior while their child was / is on Concerta? Our 8 year old son developed this odd behavior 6 months into taking Concerta. His morning, pre-medicated, behavior was so out of control, so frightening, that there was no way we could forget to give him his medicine (18mg). After 2 years, this "mania" grew in intensity and was manifesting later in the day. It took us over a month to wean him slowly off Concerta, plus another month completely off the medication before this behavior disappeared. He was clinically "psychotic" during this time. It was quite frightening, and dangerous.