DEFENSE OF MENTAL ILLNESS - REQUIREMENTS
The existence of mental illness standing alone is not sufficient to establish the Defense of Mental Illness. Instead, a person is not guilty by reason of mental illness when that person committed the act for which the person has been charged while mentally ill and was either unable to understand the nature and consequences of his/her actions or was unable to differentiate right from wrong, and has not been diagnosed with antisocial personality disorder which substantially contributed to the act for which the person has been charged.
Notes on Use
The major difference between not guilty by reason of mental illness and guilty with a mental defect is whether the defendant has been diagnosed with antisocial personality disorder that substantially contributed to the act for which the defendant has been charged. The governing statute, 22 O.S. Supp. 2017, § 1161, defines antisocial personality disorder by reference to the definition in the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5), or its subsequent editions. This condition is commonly called sociopathy, and it is characterized by a pervasive pattern of disregard for, or violation of, the rights of others and an impoverished moral sense or conscience.