Half of the people arrested in London may be living with undiagnosed attention deficit hyperactivity disorder (ADHD), according to new research from the University of Cambridge – a finding that raises urgent questions about how the criminal justice system identifies and responds to neurodevelopmental conditions. Drawing on data from police custody suites across the capital, the study suggests that undetected ADHD is far more common among detainees than in the general population, with potential implications for reoffending rates, rehabilitation programmes and the way frontline officers are trained. As policymakers grapple with soaring prison costs and persistent cycles of crime, the research adds weight to calls for routine screening and better mental health support at the very first point of contact with the law.
Undiagnosed ADHD widespread among people arrested in London new Cambridge study reveals
New research from the University of Cambridge suggests that neurodevelopmental conditions are far more prevalent in the criminal justice system than previously recognised, with nearly half of those taken into custody in the capital showing signs of attention deficit hyperactivity disorder that had never been formally identified. Researchers warn that this hidden burden may be fuelling repeat offending,missed court dates and volatile behavior in custody suites,where classic traits such as impulsivity,poor concentration and difficulty following instructions can easily be misread as defiance or aggression. Officers and custody staff, the study argues, are often placed on the frontline of undetected mental health and neurodiversity issues without the tools or training to respond effectively.
According to the findings, early screening and targeted support in police stations could transform outcomes, both for individuals and for a system struggling with high rates of reoffending. The study points towards a shift in policing culture, highlighting practical measures such as:
- Routine ADHD screening in custody suites for adults and young people.
- Specialist training for officers to distinguish behavioural symptoms from purposeful non-compliance.
- Referral pathways connecting detainees with NHS and community mental health services.
- Adjustments during interviews, including shorter sessions and clearer, step-by-step instructions.
| Key Insight | Implication |
|---|---|
| High rate of undetected ADHD in custody | Need for systematic screening at first contact with police |
| Symptoms mistaken for non-cooperation | Risks of escalation and inappropriate disciplinary responses |
| Untreated ADHD linked to reoffending | Possibility for early intervention to break offense cycles |
How missed ADHD diagnoses fuel reoffending and overwhelm police custody suites
In cells designed for short stays, frontline officers frequently encounter the same faces again and again, frequently enough for impulsive, low-level offences. When underlying neurodevelopmental conditions go unrecognised, behaviour is more likely to be labelled as “non-compliant” or “disruptive” rather than symptomatic, driving a cycle of arrest-release-reoffending. The results are felt immediately in custody suites, where staff must cope with detainees who struggle to follow instructions, regulate emotions or wait calmly for legal checks and assessments. This accelerates tensions and incidents of self-harm, while diverting officers from other critical tasks. Instead of early screening and tailored support, the system leans heavily on short-term containment, leaving root causes untouched.
The knock-on effect is a custody environment under near-permanent strain. Booking teams, healthcare professionals and supervising sergeants become de facto crisis managers, with limited tools beyond observation cells and restraint protocols. Evidence suggests that even modest adjustments can make a difference, including:
- Routine neurodiversity screening at first point of contact
- Quiet, low-stimulus areas to reduce sensory overload
- Clear, simple interaction and written instructions
- Rapid referral routes to clinical assessment and support
| Current reality | Potential outcome with ADHD recognition |
|---|---|
| Repeat arrests for impulsive offences | Targeted treatment and reduced reoffending |
| Overcrowded, volatile custody suites | Calmer environments and fewer critical incidents |
| Officers tied up managing crises | More capacity for neighbourhood and preventive policing |
Why current screening in the criminal justice system fails neurodivergent suspects
The early stages of police contact rely heavily on quick visual assessments, brief interviews and standardised risk checklists. These tools are built around assumptions of how a “typical” suspect behaves: maintaining eye contact, responding calmly under pressure and answering questions in neat, linear sentences. For someone with undiagnosed ADHD or other forms of neurodivergence, this is an invisible trap. Traits such as fidgeting,interrupting,inconsistent answers or apparent “non-compliance” might potentially be read as aggression,evasiveness or deliberate obstruction.Current screening rarely distinguishes between neurological difference and wilful defiance, meaning that people who most need tailored support are the least likely to receive it.
In custody suites and courts,the problem deepens because screening is often:
- Voluntary – suspects must self-identify,even when they lack a formal diagnosis.
- Rushed – officers are under time pressure, leaving little room for nuanced assessments.
- Generic – forms focus on physical and severe mental illness, not attention or processing differences.
- Under-trained – staff may not recognize ADHD beyond stereotypes of “hyper” behaviour.
| Screening focus | What gets missed |
|---|---|
| Suicide risk | Impulsivity and self-sabotage linked to ADHD |
| Substance use | Self-medication masking attention problems |
| Communication needs | Slow processing, overwhelm, sensory overload |
Without structured, evidence-based tools designed for neurodivergent presentations, the system continues to flag “danger” where there is actually unmet clinical need, entrenching a cycle of misunderstanding from first arrest through to sentencing.
What policymakers must do now to improve assessment diversion and support for ADHD
Faced with evidence that neurodevelopmental conditions are widespread in custody, decision‑makers need to hard‑wire early identification and support into every stage of the criminal justice pipeline. That means funding rapid, trauma‑informed screening in police stations and courts, embedding specialist ADHD clinicians in liaison and diversion teams, and requiring data reporting by region, gender and ethnicity to expose gaps in provision. Police, magistrates and probation staff should receive mandatory training on how ADHD can shape behaviour, communication, and apparent “non‑compliance”, backed by national guidance that discourages custodial remand where clinically indicated needs are unmet. To make this more than a pilot‑project patchwork, ring‑fenced budgets must be attached to performance targets, ensuring that local services cannot quietly drop neurodiversity work when resources tighten.
Effective reform also depends on building a bridge between justice, health and housing systems so that a diagnosis becomes a route to stability rather than a label attached in prison.Policymakers should broker integrated care pathways that guarantee fast‑track assessment, timely access to evidence‑based medication, and community follow‑up on release, alongside practical support such as employment coaching and debt advice. Crucially, people with lived experience of both ADHD and the justice system must be given a formal role in programme design and oversight, from national advisory panels to local scrutiny boards. This can be underpinned by targeted investments in:
- Early diversion schemes in custody suites and youth offending services
- Community‑based ADHD clinics linked to probation and rehabilitation providers
- Digital tools for screening, case tracking and appointment reminders
- Independent advocacy to help individuals navigate complex legal and clinical processes
| Policy Action | Main Goal | Lead Agency |
|---|---|---|
| Routine ADHD screening at arrest | Early identification | Police & NHS |
| Clinicians in every court | Informed sentencing | MoJ & Courts Service |
| Post‑release care plans | Reduced reoffending | Probation & ICBs |
In Summary
As the justice system grapples with rising caseloads and chronic resource shortages, these findings from Cambridge point to a stark choice: continue treating ADHD as incidental background noise-or recognise it as a central factor in why so many people end up in handcuffs in the first place.
For policymakers, police and mental health services alike, the study serves as both a warning and an opportunity. If even a fraction of those cycling through London’s custody suites are living with undiagnosed, untreated ADHD, then early screening, better access to assessment and tailored support could become powerful tools not just for public health, but for crime prevention.
The research does not excuse offending, and it does not offer a quick fix. But it does recast the profile of the “typical” arrestee and raises uncomfortable questions about how many people are being punished for symptoms that were never recognised, let alone treated. As more data emerges, London may prove to be less an outlier than a mirror-reflecting systemic blind spots that extend far beyond the capital’s police cells.
