ADHD is over-represented within the criminal justice system. A meta-analysis of 42 studies indicated that 25.5% of the prison population met the criteria for ADHD. These data suggest that compared with the general population, the prevalence of ADHD is 5-fold higher in youth prison populations (30.1%) and 10-fold higher in adult prison populations (26.2%) (Young S, 2015). This review adds to the literature on ADHD and criminal law by indicating how ADHD is being factored into courts.
In the UK, the Youth Justice Legal Centre highlights that is important for police to know whether a child has ADHD, as this may affect how the police treat the child, how they view the child’s behaviour and whether a child receives a criminal record. In addition, the way police interviews are conducted can be modified to make it easier for children with ADHD to answer questions and provide evidence. An intermediary can be used to aid communication with the child, and the interview should be conducted in the presence of an appropriate adult. If a child is either a witness or victim of a crime then it is important for the police to know if that child has ADHD. It is also important that children with ADHD can effectively participate in the court process, which could be aided by modifications such as regular breaks for movement and medication, the opportunity to doodle, use of a therapy cushion or a stress ball, and explaining that fidgeting is not a sign of disrespect. If a child is a defendant or a witness, additional measures can be used, such as use of an intermediary when preparing or giving evidence, to aid communication when providing evidence or to explain what is happening in court (Youth Justice Legal Centre, 2018).
The potential relevance of ADHD for sentencing has been accepted in a series of judgements by the Court of Appeal in England and Wales. Moreover, guidance highlighting limitations in terms of implications that can be drawn from no more than reference to the existence of ADHD in an offender has been provided by the Western Australian and New Zealand Court of Appeal. ADHD can be critical in explaining and contextualising engagement in criminal activity and predicting the likelihood of reoffending. The symptoms of ADHD, such as impulsiveness, inattentiveness, inability to retain information and limitations to the ability to think consequences through rationally are all factors that may contribute to a crime. A diagnosis of ADHD does not provide a defence or a significant mitigation of culpability. However, this may depend on the type of ADHD symptoms experienced by the accused, the conduct they were engaged in and the extent to which their ADHD symptoms played a role in their conduct. Nevertheless, ADHD could be relevant to fitness to stand trial and may provide a partial defence of diminished responsibility, where applicable. ADHD could also explain other factors, such as the voluntariness of police interviews, the reasons behind an individual not providing evidence and potentially any unusual conduct in court, which could be misinterpreted. ADHD is particularly relevant during the sentencing phase, as this may cause the offender problems with self-regulation and impulsivity, with time in prison potentially being more difficult than for those without ADHD. The context behind problematic judgement and antisocial behaviour could also be explained by ADHD.
ADHD is often associated with psychiatric comorbidities, which may make it difficult for forensic practitioners to disentangle the factors that may have contributed to a crime. Moreover, this could increase the potential for reoffending. However, if an individual is prepared to be adherent to medication for their ADHD, this could reduce symptomology and the likelihood of ongoing criminal offences. For example, using data from Swedish national registries (n = 25,656 individuals with ADHD), there was a 32% and 41% reduction in the criminality rate of men and women, respectively, between 2006 and 2009 among those who took their ADHD medication (Lichtenstein P, 2012).
It is noted that unless there is expert evidence regarding the impact of ADHD on an offender’s conduct, ADHD will not be taken into account during sentencing. Moreover, for mental health practitioners’ opinions about ADHD to be helpful, they will generally need to have diagnostic expertise and have examined the individual in question. An offender’s self-reports of ADHD, and their parents’ reports, must not overly influence an expert witness and critical clinical judgement must be implemented. Additionally, if an offender has consumed illegal drugs, this may have played a role in causing disinhibition, which may render an ADHD diagnosis less valuable in mitigation.
Finally, a central issue is the extent to which an offender’s ADHD symptoms caused or at least were a contributing factor leading to a criminal offence. The relevance of an ADHD diagnosis may be invalid if there is clear evidence that the crime was premeditated and planned. However, an additional consideration at sentencing should also be the level to which ADHD symptoms may be heightened by the custodial environment or make an individual with ADHD more vulnerable.
Read more about the impact of ADHD and the criminal law here
Freckelton I. Attention deficit hyperactivity disorder (ADHD) and the criminal law. Psychiatr Psychol Law 2020; 26: 817-840.
Lichtenstein P, Halldner L, Zetterqvist J, et al. Medication for attention deficit-hyperactivity disorder and criminality. N Engl J Med 2012; 367: 2006-2014.
Young S, Moss D, Sedgwick O, et al. A meta-analysis of the prevalence of attention deficit hyperactivity disorder in incarcerated populations. Psychol Med 2015; 42: 247-258.
Youth Justice Legal Centre. Attention deficit hyperactivity disorder (ADHD). Available at: https://yjlc.uk/adhd/. Last updated September 2018. Accessed April 2020.