Half of people arrested in London could have undiagnosed attention-deficit hyperactivity disorder (ADHD), a study has suggested.
Researchers at the University of Cambridge offered people detained at six London Metropolitan Police custody centres voluntary screening for ADHD and autism over an eight-week period.
The results showed one in two people arrested in the capital scored high enough in the screening to warrant further assessment for ADHD, and 5 per cent were thought to have undiagnosed autism.
Researchers behind the study said the results could help officers interpret behaviours that might be “misunderstood” and ensure appropriate support is provided.
Neurodivergent individuals – particularly autistic people and those with ADHD – are overrepresented within prison populations, according to the study published in the journal Criminal Behaviour and Mental Health.
Dr Tanya Procyshyn, a research associate at the Autism Research Centre at the University of Cambridge, said: “To ensure fair treatment in the criminal justice system, we need to understand how neurodivergence affects interactions with the law. This can help avoid unnecessary criminalisation of misunderstood behaviour and ensure that potentially vulnerable individuals are able to access appropriate support.”
Dr Procyshyn and Dion Brown, a senior detective from the Metropolitan Police Service, co-led a study to explore the feasibility of screening arrested individuals for traits related to ADHD and autism and to examine the reasons leading to the arrest.
ADHD traits were assessed using a modified version of the adult ADHD self-report scale. Autistic traits were assessed using the 10-item autism-spectrum quotient.
Those who scored above the thresholds for ADHD or autistic traits were informed and given additional information on how to seek a formal diagnosis.
Out of the 303 offered a screening, 71 per cent accepted and 8 per cent already had an ADHD diagnosis. That is 3 per cent higher than in the general population. Out of those who scored above the threshold for ADHD, 17 per cent had a very high number of ADHD traits.
Nine individuals (4.2 per cent) had an existing autism diagnosis, which again is slightly higher than the prevalence of autism in the general adult population (3 per cent). An additional 5.4 per cent scored at or above the threshold for possible undiagnosed autism.
More than half (60 per cent) were arrested for drug offences and had an existing diagnosis or positive screening result for ADHD. This supports previous studies, which have found that some neurodivergent individuals may self-medicate with illegal substances.
But research shows people with ADHD are less likely to engage in criminal behaviour when taking medication for ADHD.
Detective Brown said: “Early identification helps officers interpret behaviours that might otherwise be misunderstood and ensures appropriate support is provided. This approach creates opportunities to divert vulnerable individuals away from the criminal justice process and towards the help they may need.”
