For information or to initiate a petition, call our office at 612-348-2787. Procedure. A defendant who intends to assert a defense of insanity at the time of the alleged offense must so notify an attorney for the government in writing.Learn about civil commitments in Hennepin County, affecting mentally ill or chemically dependent people likely to substantially harm themselves or others. Rule 14.01Pleas Permitted. A defendant may plead: (a) Guilty. The insanity defense exists to make that distinction for people with a mental disability. In an insanity defense, the defendant admits the action but asserts a lack of culpability based on mental illness. 49 counties in 9 states, PTSD was the basis of an insanity plea in only 0.3 percent of cases. For these reasons, hiring a criminal defense attorney is advisable if you're considering pleading insanity in a criminal case. FAQs. You are not required to have an attorney to fill out this application.