Can Conerta Cause Seizures?

My 10 year old son began having seizures about 2 months after starting Concerta.  No family history of seizures.  He has complex partial and we are in the midst of trying to find a med that works.  We want to d/c the Concerta, but sources say it can't be the Concerta b/c if it was, the seizures would have happened immediately.  We took him off Concerta for 2 weeks and he still had seizures- no change.  We put him back on b/c his behavior was intolerable.  Please give any advice/thoughts.  Thanks.