My husband has had several CT scans without contrast which show he has prominent cisterna magna anatomic variant. I can't seem to find a clear answer to what this is. He has had several TBIs since 1995 to the present. He was seen by a psychiatrist who diagnosed him with bipolar disorder, OCD and ADHD. Could this be the reasone for these mood disorders? Is this something he was born with or did it occur from the TBIs?