Insanity, what does it mean?
Insanity is a legal construct, not a psychological one. Depending on the jurisdiction, the definition of insanity can vary. Many states use the M’Naghten rule (or some variation of it) in determining insanity. This is a two-pronged test that originated from England in 1843.
California is one of many states that uses the M’Naghten rule. The expert is tasked with determining if, as a result of mental disease or defect,
1) The defendant did not understand the nature and quality of their act, or
2) The defendant was unable to distinguish between right or wrong.
The burden of proof generally rests on the defense. The mere presence of a mental illness in and of itself is usually insufficient in concluding that one was insane at the time of the crime(s). But rather, it is how symptoms of mental illness impacted the defendant’s appreciation of the crime(s) or their ability to distinguish between right and wrong.
A plea of not guilty by reason of insanity falls within penal code (PC) 1027. A PC 1027 evaluation involves multiple steps. Once the plea is entered, the Court appoints a forensic psychologist or psychiatrist to conduct a forensic evaluation. It is not uncommon for there to be an appointment of more than one doctor. The doctor reviews relevant records and collateral information, conducts a forensic interview with the defendant, and provides a report containing their opinion. Oftentimes, psychological testing is also involved. In fact, this is almost always the case in my practice because it offers additional data points to consider and can bolster the strength of the opinion.
In felony cases in California, if a defendant is found to have been legally insane, they are usually committed to a state hospital for an undetermined length of time in order to receive treatment. If and when they are deemed to have been restored to sanity, they can potentially be conditionally discharged to community supervision, and eventually, can also potentially be unconditionally discharged. More on restoration of sanity in a future blog post.
Dr. Chan is a forensic psychologist in San Francisco. He conducts PC 1027 evaluations and provides expert witness testimony. To discuss a case, please contact me by email, phone, or complete the contact form.
