Forensic assessment of criminal maturity in juvenile homicide offenders in the United States

The United States Supreme Court in Jones vs. Mississippi (2021) reinforced the Miller decision to allow sentencing judges the discretion to determine whether individuals convicted of murder under age 18 warrant a life sentence. The Miller decision dictates individualized sentencing, citing psychosocial disadvantages, immaturity, potential evolving risk, and how these qualities differ for each defendant. Since the Miller decision, mental health professionals routinely submit forensic reports as part of prisoners’ petitions to courts for reconsideration of their life sentences, either at the request of defense attorneys or prosecutors. This tracks a well-established practice of pre-sentencing evaluations. The expressions of immaturity in crime are not; however, accounted for in the same way that expressions of major mental illness reference years of crime-specific research and diagnostic standardization. For this reason, forensic assessments in this emerging area remain unguided and vulnerable to bias. Here, we present a guide containing 38 questions in seven developmental domains for individualized assessment and 50 questions spanning five domains that relate to the details of the crime. Our qualitative guidelines for assessment of the relevant domains of criminal maturity and offender prognosis draw on the forensic psychiatry, forensic pathology, developmental psychopathology, and criminological literatures, our experiences in comparative research of murder, sex assault and other crimes, as well as decades of experience in forensic assessment. A complete assessment of the offender should include questions in the developmental, scholastic/vocational, social, interpersonal, traumas, antisocial history, and psychiatric/medical domains. We also present recommended questions for assessing the details of the crime to more fully and accurately inform the individualized sentencing requirement in Miller cases.