Addiction is a brain disease, and it doesn’t matter: prior choice in drug use blocks leniency in criminal punishment

Our aim was to explore how (neuro)scientific understanding of addiction as a brain-disease impacts criminal sentencing decisions in courts in England and Wales, where legal rules concerning intoxication, prior-fault and mental disease conflict, and sentencing guidelines lack clarity. We hypothesized that despite significant neuropsychiatric overlap of addiction and other brain-disorders, variables in relation to etiology would moderate magistrates’ sentencing decisions in cases involving addicted offenders. Using a questionnaire-based, quantitative design, and combining frequentist and Bayesian analysis approaches, we probed court magistrates’ sentencing decisions, and underlying rationale, for defendants presenting with brain damage resulting from a (fictional) disease, addiction to heroin, or more complex, mixed etiologies. When identical neuropsychiatric profiles resulted from disease, but not heroin addiction, prison sentences were significantly reduced. Study 1 (N=109) found the pivotal factor preventing addiction from mitigating sentences was perceived choice in its acquisition; removing choice from addiction increased the odds of sentence reduction (~20- fold) and attaching choice to disease aggravated or reversed earlier leniency. Study 2 (N=276) replicated these results and found that when heroin use led to disease or vice versa, magistrates found middle ground. These differences were independent of the age of first drug use. Finally, evidence of addiction was more likely to evoke punishment considerations by magistrates, rather than rehabilitation. Consistent with legal rules relating to intoxication but running counter to norms around mental-illness and choice, our results demonstrate the need for greater clarity in sentencing guidance on addiction specifically, and mental disorders more generally.