You are asking two different questions. A schizophrenic may have an altered view of his/her own reality and may not be aware of his/her acts. A person must be aware of his/her acts in order for a polygraph to work. A pathological liar, however, does know that he/she committed the offense in question and understands the consequences, so the test will work fine on them. - Michael Martin (President, Global Polygraph Network)
I know one that just did. I know for a fact that he committed a crime and passed one for the police in Henry County, Georgia. I was wondering how, so I googled it and your question popped up.