In People v. Stevens, the Supreme Court today examines the use of expert testimony to support a civil commitment during parole of a state prisoner under the Mentally Disordered Offender Act (MDO). The court’s unanimous opinion by Justice Ming Chin holds that “a mental health expert’s testimony in support of a defendant’s MDO commitment may not be used to prove the defendant committed a qualifying offense” and that “mental health experts may not testify about a topic that is not ‘sufficiently beyond common experience that the opinion of an expert would assist the trier of fact.’” The court explains that “proof of a qualifying conviction under the MDO Act is based on facts rather than on defendant’s psychological condition, and thus does not call for a mental health expert’s opinion testimony.”
The court reverses the Second District, Division Six, Court of Appeal. It also disapproves a 1994 opinion from that same court and it aligns itself with a 2012 decision from the Fourth District, Division Two, Court of Appeal.
