ADHD drug treatment reduces violent crime

Research suggests a strong protective effect. Meanwhile, Australian treatment pathways remain hopelessly blocked.

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People with ADHD who are medicated commit fewer crimes of a violent or public-disorder nature, a new study has found.

Norwegian researchers, using population-level registry data, looked at all 10-18-year-olds diagnosed with ADHD in Norway between 2009 and 2011 – a cohort of more than 50,000 – and looked at their medication use and subsequent criminal charges over eight years of follow-up. They exploited the natural variability in health providers’ willingness to prescribe ADHD drugs as a form of randomisation.

Their results clearly suggest that use of medication reduced criminality associated with impulsiveness, with numbers needed to treat (NNT) of 14 to prevent a crime of violence and just eight for a crime of public disorder.

For crimes requiring premeditation, conspiracy and planning, there was no effect.

While the prevalence figures are stark – around 6% of children, 2.5% of adults and 25% of prison inmates have ADHD – previous research on medication and criminality has had mixed results, the authors write.

“There’s no doubt that criminality is increased among the ADHD population, particularly with emotional dysregulation, aggression, poor impulse control and risk-taking behaviours,” Dr Shannon Morton, a psychiatrist at Kooky Clinic in Brisbane, which specialises in ADHD, told The Medical Republic.

“They’re overrepresented with disruptive behavioural problems, substance use, getting in trouble with the law, and other impulse-control problem outcomes, including traffic offences … as well as other misadventure.”

She said the study design revealed a protective effect for patients “on the margin of treatment” – that is, not the severest cases, who are both more likely to receive medication and to commit crimes, a potential confounder.

“It’s a conservative methodology of establishing a causative protective factor with the medications,” she said.

The study did not consider adherence rates, Dr Morton said, and given that ADHD patients are “notoriously non-adherent long term” because of the nature of the condition, that made the results all the more impressive.

Other factors that made the result a likely underestimate were the cohort’s young age, the fact crimes had to result in charges and the fact that ADHD drugs are generally not taken at night, when crime is more common.

As well as by type of crime, the results were stratified by sex. Females were much less likely to be charged with crimes than males.

Dr Morton said the potential for criminality, usually reckless driving or aggressive or antisocial behaviour, was a factor in decision-making around prescribing ADHD meds.

“We use medication when a condition is causing distress or disability or risk of harm,” she said. “So if a young person is engaging in or at risk of serious criminal behaviour, then that would be a risk of harm.”

Dr Morton said the Australian situation was different from Norway’s, where all patients go through the public mental health system.

In Australia, the same cohort would be treated in a mix of public and private systems, with different socioeconomic conditions and different attitudes to prescribing.

“A lot of the kids that have higher-order violence and impulse-control problems are often seen in the [Australian] public system, but they’re less likely to get their ADHD treated in the public system because culturally there’s a focus on their social difficulties and family, trauma, abuse and neglect. There are significantly different prescribing cultures in the different systems.”

Dr Morton said there were cultural concerns around prescribing stimulant medications to people with substance-use problems, and a lot of neurodiverse people self-medicated.

She said concerns about abuse of ADHD medication were “overblown”, that non-adherence was the greater worry, and that long-acting formulations like the popular lisdexamfetamine (Vyvanse) did not act in the same way as street amphetamines.

There was also a false dichotomy in diagnosis between ADHD and complex trauma, due to the condition’s heritability.

“It’s very common that people will have both, because if their parents had ADHD and had impulse control and emotional regulation problems, then they’ve often got both the genetics and the traumatic upbringing,” she said. “It’s actually more common than not that there’s different degrees of trauma overlying that neurobiology.”

A Deloitte report in 2019 estimated the economic burden of ADHD in Australia at $20 billion a year, with crime and justice contributing 3% of that cost.

Dr Morton said it would be highly cost-effective to invest in making assessment and treatment accessible. Instead, “shortsighted” policy settings had contributed to a bottleneck in which it was slow, prohibitively expensive or impossible to get a diagnosis, and then confusing and expensive again to find a specialist who can formalise a diagnosis and prescribe.

An “industry” had also sprung up that exploited patients by offering unnecessary layers of expensive testing.

Kooky Clinic, where Dr Morton works, uses a case conferencing system in which a GP with special interests can manage the patient with the help of a specialist.

Unfortunately, that model is not supported by Medicare, which requires at minimum the GP, the specialist, an allied health professional and the patient to be in the room at once – an impossible feat of scheduling.

“There’s never going to be enough specialists to service that (5-7%) of the population,” Dr Morton said. “The government really needs to be thinking strategically about the cost savings if it were to support models that did dramatically improve the local GP’s ability to competently assess and treat ADHD with specialist backup.

“We need to build workforce capacity and there’s just not enough specialists and there never will be, so the only option is to support GPs.”