How to set aside release

What is the name of your state (only U.S. law)? Oregon

I was in a car accident and suffered post concussive syndrome. I settled my claim myself not realizing exactly what I was doing. My psychiatrist says I wasn't competent to sign the release. Is there any chance I can get this set aside? I have had numerous medical bills and a year and a half later am still unable to work.

It's very, very unlikely, but take the advice and your medical records to a lawyer and see what he/she says.

There is another element involved in rescinding a contract - besides having legal cause - and one that you may not have considered.

Which is that the consideration received must be restored to the other party. Are you prepared to do that?

No matter what the grounds, fraud, coercion mutual mistake, incapacity, etc, you CANNOT expect to void a contract and yet retain the benefits of the contract. The law will not permit you to have it both ways.