My sister is bipolar. Our grandson had surgery for chiari. Can one have anything to do with the other? His behavior has changed drastically in the past year - from sweet and very calm to what I call a very high. I recognized the tone of voice, the extreme self-assuredness and lack of respect. He was always so easy going, but now is just the opposite. I've seen my sister go through hell with her bipolar condition and I know that the sooner it's caught, the sooner it can be treated, but never cured. The operation for chiari seems to have done the trick. The bone was so thick at base of his skull, that they had to use a larger instrument. He suffered a great deal after the surgery. I am his grandmother on his mother's side. Four years ago his 10 year old brother died from a broken blood vessel in his cerebellum. They told my daughter and her husband that he had a tumor and the blood vessel burst inside the cerebellum, but I think he'd surely had some symptoms - very small town in South Carolina. He was taken to an MD (not a pediatrician) and it took 16 hours from the sudden headache and death. He had 6 siblings, all of which seem to be healthy, except for Jake's sudden change in personality.