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The Brown & Crouppen Legal Lens takes a closer look at everyday legal issues and gives you a better understanding of topics that may affect you.

ST. LOUIS — When a person commits a crime but is found to have a mental illness, what happens? Andrea McNairy, the managing attorney for Brown & Crouppen, explains in this week’s Legal Lens.

“In Missouri, insanity is a defense that’s recognized,” said McNairy. “The theory being if the defendant can not recognize that their actions are wrong, then they can’t be legally or morally guilty of them. So, in Missouri, a defendant can’t be guilty if they had a mental illness at the time they committed a crime.”

The M’Naghten Rule would apply to this type of case. It asks if the defendant knew or understood that their actions were wrong at the time the crime was committed, McNairy explained. Yet, criminal defendants found legally insane don’t necessarily go free.

“Since they can’t distinguish right from wrong, they are usually committed for some period of time for treatment in a mental health facility,” McNairy said. ” If they can’t be sufficiently taught the seriousness of their actions they would have to stay there until a judge deems them legally fit or not insane anymore.”

If there is great concern that a person may commit a crime due to a mental illness, Missouri law recognizes something called “civil involuntary detention.” It allows someone to be involuntarily detained under certain criteria or conditions.

“They can be held for up to 96 hours,” McNairy said. “Any adult can file for this in a circuit court for another person. So police officers, EMS, and physicians can immediately detain someone. If you think it’s an emergency and somebody is having a mental health crisis and may hurt themselves or another, get that person to an ER or call the police.”

If it is not an emergency, you can call the access crisis intervention line. Each county has a different number. For more information, visit: