"I had a 2cm brain aneurysm surgery 13 years ago and survived. One year after the brain surgery I had a lot of blank spots. I went and saw a Doctor and explained my situation and he put me on Ritalin. It has helped me tremendously without a doubt. If there are any side effects I haven&#039;t seen them. When I don&#039;t take Ritalin those blank spots come back. I usually take Ritalin 6 days a week and I do not have any withdrawals of any kind. "