Luigi Mangione plans to assert a psychiatric defense at his state murder trial, claiming he was suffering from extreme emotional disturbance when he gunned down UnitedHealthcare CEO Brian Thompson, a judge said Wednesday.

Psychiatric Defense Explained

An emotional disturbance defense is not the same as a not guilty by reason of insanity defense, which would allow a defendant to go to a psychiatric facility instead of prison. To establish an emotional disturbance defense, Mangione’s lawyers must demonstrate that the disturbance was so extreme it robbed him of self-control; that, in his mind, there was a reasonable explanation for the disturbance; and that it influenced him to kill Thompson.

Heather Cucolo, a New York Law School professor and expert in mental health law, said Mangione’s lawyers could try to accomplish that by having a psychologist testify about his mental state at the time of the killing and the extent of any trauma, abuse or emotional instability he’s suffered.

Prosecutors say Mangione planned the attack, wrote in a notebook about wanting to ‘wack’ a health insurance executive and traveled from out of state to ambush Thompson, 50, as the CEO walked to a Manhattan hotel for an investor conference.

Original reporting: Texarkana Gazette — read the source article.