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Law and Crime

Youthful Killers Need In-Depth Review

A team of experts has made an assessment guide for judging incorrigibility.

Key points

  • Court decisions regarding juvenile killers have noted the role of the immature brain.
  • One decision recognizes the differing psychosocial disadvantages, maturity levels, and potential for future violence among defendants.
  • A team of researchers has devised questions to help standardize evaluations of these differences.
Photo by K. Ramsland
Photo by K. Ramsland

Over the past two decades, we’ve seen half a dozen significant court decisions on sentencing for youthful offenders, due in part to the findings of neuroscience about the adolescent brain. The latest decision, in Jones v. Mississippi (2021), affirms judicial discretion but lacks guidelines. Participants on the Forensic Panel have devised a helpful guide for a standardized approach. In an effort to eliminate bias, the assessment draws broadly on seven life domains and five domains related to the criminal act.

Forensic psychiatrist Michael Welner led the study. His team developed the Depravity Scale, which offers standardized “aggravating factor” guidelines to courts based on extensive peer feedback. When certain acts are called cruel, wanton, vile, cold-blooded, or monstrous, these imprecise labels encourage juries to make emotion-based, often biased judgments.

"From my own experience consulting as a forensic psychiatrist to both prosecutors and defense attorneys," Welner stated, "I see these terms being thrown around in capital and other criminal, even civil and family court cases, and I recognize how difficult it is for a judge or jury—let alone a forensic mental health professional—to try to define them in any consistent and non-arbitrary way. We need consistency, and in particular consistency that reflects the best that forensics has to offer.”

Juvenile Crime

With teens, these decisions can be just as random. Given the lifelong impact, care is warranted. Evidence shows that the stage of life between ages 12 and 19 is different in significant ways from adult stages. It’s a time of experimentation, exploration, exaggerated emotions, feelings of invincibility, and the onset of certain mental illnesses.

Teens are also highly vulnerable to peer pressure, especially when it’s something dangerous, rebellious, harmful, or criminal. They feel an urgent need to belong and have a social identity. Decisions can be made without considering their potential life-changing consequences.

As the legal system has absorbed this information from the fields of cognitive psychology and neuroscience, evaluating criminal responsibility has grown more cautious. According to several decisions by the U.S. Supreme Court since 2005, teens should not be executed for serious crimes (Roper v. Simmons), receive life sentences for non-homicidal crimes (Graham v. Florida), or have automatic life sentences without the possibility of parole (Miller v. Alabama) unless they’re deemed permanently incorrigible. The decisions are retroactive (Montgomery v. Louisiana), and Jones v. Mississippi affirms judicial discretion for evaluation. Yet leaving the prognosis for possible future criminality up to individual clinical opinion or to triers-of-fact makes it vulnerable to partiality, superficial data gathering, and ignorance.

“Teens are different,” writes forensic psychologist James Garbarino, author of Miller’s Children, “and traumatized teens are more different.” Based on multiple interviews with teenage killers, Garbarino points out that “teenage killers are not playing with a full deck when it comes to making good decisions and managing emotions…but many of them are also playing with a stacked deck because of the developmental consequences of adverse life circumstances.”

Among those adverse circumstances listed by the CDC are poverty, domestic abuse, maltreatment, household substance abuse, divorce, depression in a family, and the incarceration of a family member. Nearly 40 percent of adolescent killers have at least five of these factors vs. 10 percent of kids from the general population.

The grounds offered in Miller v. Alabama for rejecting mandatory life without parole for teens involves not just immature brain development but also a youth’s actual role, a rough home environment from which kids cannot extricate themselves, and their potential for rehabilitation. Yet it’s not easy to decide which factors bear more weight, especially for kids with critical disadvantages.

The Assessment

Welner’s team recognizes these concerns. “Forensic assessments in this emerging area remain unguided and vulnerable to bias,” they write. They urge that an assessment of the immaturity factors and prognosis prediction of any youthful offender should include items from seven different life domains: developmental, scholastic/vocational, social, interpersonal, traumas, antisocial history, and psychiatric/medical. They offer a set of questions from each area. For example, in the developmental area, where they’re aware from research that 91 percent of juvenile killers had a negative relationship with a male caretaker, they ask, “What is the quality of the offender’s relatedness to each parent?” There are 38 questions in total from the seven areas.

They also offer 50 questions from five domains related to the criminal act: the crime’s antecedents, the crime specifics, relatedness to the victim, the aftermath, and other influencing factors. Was it premeditated, for example, or impulsive? What options did the offender consider as an alternative to murder?

The researchers contend that “the impact of potential evaluator bias is counterbalanced by the quality and quantity of history about the crime and the defendant’s background.”

It’s a comprehensive assessment, to be sure, and if this approach were to be adopted, it would likely have the intended effect of reducing arbitrary decisions, supporting fairness, and building a standardized database that would serve future generations. Yet, whether or not the approach is broadly accepted, any clinician in a position to evaluate juvenile murderers for the court would benefit from this carefully curated list.


Garbarino, J. (2018). Miller’s children: Why giving teenage killers a second chance matters for all of us. University of California Press.

Heide, K. M. (2021). Juvenile homicide offenders: AA 35-year follow-up study. Behavioral Sciences and the Law, 39(4), 492-505.

Moreira, D., Sá Moreira, D., Oliveira, S., Ribeiro, F. N., Barbosa, F., Fávero, M., & Gomes, V. (2020). Relationship between adverse childhood experiences and psychopathy: A systematic review. Aggression and Violent Behavior, 53, Article 101452.

Welner, M. DeLisi, M., Knous-Westfall, H., Salsberg, D., & Janusewski, T. (2023). Forensic assessment of criminal maturity in juvenile homicide offenders in the United States, Forensic Science International: Mind and Law, 4, 100112,

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