Psychiatric prevalence

Despite their pervasiveness, neurodivergence and associated psychiatric consequences remain poorly understood and inconsistently managed within healthcare systems. Service fragmentation means that neurodivergence is often approached piecemeal, with clinicians seeing parts of, but rarely the whole, picture. This evokes the parable of blind men each describing a different aspect of an elephant. The issue is large yet hides in plain sight: the elephant in the room. In routine psychiatric populations, around 22% of patients are estimated to have ADHD ^{Reference Johnson, Lim, Jacoby, Faraone, Su and Solmi3} whereas perhaps up to 20% meet, or probably meet, the diagnostic criteria for autism. ^{Reference Nyrenius, Eberhard, Ghaziuddin, Gillberg and Billstedt4} In emergency settings, these numbers may be even higher: one recent service evaluation found that 15% of adults presenting in crisis carried a confirmed diagnosis of autism and, staggeringly, at least 50% met screening criteria. In child psychiatry, a quarter of emergency attendees are reported to have an ADHD or autism diagnosis; the proportion undiagnosed is unknown. Such figures expose a gap in detection: common neurotypes, strongly associated with poorer clinical outcomes, can appear invisible within much of practice.

The co-occurrence of neurodivergence and primary psychiatric disorders compounds this challenge. Among individuals with a first episode of psychosis, up to 40% are suggested to be neurodivergent: psychotic symptoms emerge around a decade earlier in such patients, who require twice as much acute care. ^{Reference Nikolić, Sculthorpe, Stock, Stevens and Eccles5} Similarly, high rates of ADHD and autism are described in patients with a bipolar diagnosis. Obsessive–compulsive disorder, and common mental disorders including social anxiety, panic and agoraphobia, show substantial cross-over with ADHD, autism and developmental tic disorders. This pattern is replicated across services treating addictions, eating disorders, stress-sensitive somatic syndromes and functional neurological disorders. Autistic children are estimated to represent around 15% of those presenting with functional (non-epileptic) seizures. ^{Reference Vickers, Menhinnitt, Choi, Malacova, Eriksson and Churchill6} Importantly, neurodivergence overlaps: ADHD is estimated to co-occur in up to two-thirds of autistic individuals, and autistic traits are reported to be present in half of those with ADHD. Recognition of this interconnectedness is important, both for prioritising prevention and tailoring effective intervention.

Neurodivergent patients who experience mental illness require more intensive care and are more prone to crises and relapse. Genetic, ^{Reference Rees, Creeth, Hwu, Chen, Tsuang and Glatt7} epidemiological and clinical data link neurodivergence to the same pathways that underpin schizophrenia, bipolar disorder, obsessive–compulsive disorder, anxiety and eating disorder. Risks of psychiatric illness reflect increased biopsychosocial vulnerability to environmental and social stressors, and their relationship to individual neurodevelopmental sensitivity profiles.

Poor recognition of neurodivergence carries profound consequences for both individuals and society. ADHD and autism are associated with shortened life expectancy (reportedly, ADHD ∼9 years, autism ∼6–7 years) and heightened suicide risk (reportedly ADHD ×4, autism ×3–7). ^{Reference O’Nions, El Baou, John, Lewer, Mandy and McKechnie8} A UK review in 2023 of Prevention of Future Deaths Notices found autism cited in a quarter of child suicides, the single most common recorded diagnosis. Rates of substance misuse, eating disorders, depression, anxiety and chronic pain were disproportionately higher. Educational opportunities and occupational trajectories are severely affected: UK surveys indicate that up to 40% of working-age adults with ADHD, and up to 80% of autistic adults, are unemployed. Thus, wider social costs encompass chronic unemployment, increased healthcare utilisation, elevated risks of self-harm and premature death, where systemic under-recognition translates into wasted potential, increased public costs and lost lives. Analyses indicate that, in the UK, these composite costs ¹ exceed those accrued by cardiovascular disease and diabetes together.

We know that interventions are safe and effective. The benefits of pharmacotherapy for ADHD are evident across multiple clinical and societally important metrics relevant to public health. ^{1,Reference Zhang, Zhu, Sjölander, Nourredine, Li and Garcia-Argibay2} Ongoing economic analysis of population-level improvements following evidence-based interventions should be a priority for shaping the sustainable design of services ¹ Neurodivergence will not disappear; the continued advancement of clinical knowledge informed by scientific evidence validates the case for investment in early identification and intervention, such that neurodivergence is fundamentally embedded within psychiatric formulation.

Systemic barriers continue to hamper progress: prevalence estimates within general populations differ across studies and regions, probably reflecting differences in diagnostic/screening instruments and protocols as much as differences in awareness or training. These discrepancies need to be resolved, because they have led to hesitancy in service planning and fuel a debate that is tangential to our key point, that neurodivergence within psychiatric populations is a highly prevalent and modifiable factor. Clinicians across psychiatry and primary care may not all receive the up-to-date evidence-based training necessary to recognise even the common adult presentations of ADHD and autism, increasing the likelihood that symptoms are misattributed to mood, psychotic or personality disorders alone. There is intersectional importance: neurodivergent children (and adults) have greater vulnerability to trauma for multiple reasons, ^{Reference Gajwani and Minnis9} yet narrowing formulation solely on trauma can compromise appropriate (still trauma-informed) clinical care. Likewise, neurodivergent individuals may struggle to engage with standard talking therapies due to differences in sustained attention, emotional language and sensory experience (including pain), whereas physiological differences and physical vulnerabilities (e.g. those related to hypermobility) can limit the efficacy or tolerance of pharmacotherapies. Neurodivergent individuals often experience barriers in accessing health services and report poor experiences across primary care and secondary physical and mental health settings. Organisational silos typically separate neurodevelopmental services from mainstream psychiatry, reinforcing fragmentation. Consequently, clinicians often overlook underlying neurodevelopmental characteristics in formulations and differential diagnoses of psychiatric illness. The result is a cycle of late recognition, crisis-driven care and lost opportunities for prevention. ¹ The associated tendency for binarised thinking (either neurodivergence or mental illness) can further exclude and stigmatise patients who require greater support or tailored intervention.

A public mental health approach

Effective change is necessary and achievable, building upon the interconnected principles of promotion, prevention, preparation and participation. Promotion argues for routine screening for ADHD and autism in schools, primary care and psychiatric services, supported by validated tools and comprehensive training for professionals across the public sector. Neurodivergence is a fact of life, yet the prevention of associated consequences requires early adjustments and intervention in educational, community and healthcare settings, mitigating clinical and social sequelae before they become complex and entrenched. Digital tools may facilitate the scalable implementation of screening and triage. A systemic redesign of services in needed, to be prepared and equipped to deliver equitable, effective, integrated diagnostic and care pathways. Ideally, structures should be in place before secondary care, to support timely interventions (encompassing pharmacotherapy, adapted psychotherapies and educational and occupational support). Participation means that neurodivergent voices (a largely untapped resource) must be included at all levels of discussion: there are powerful neurodiversity-affirming, third-sector and patient-led initiatives. These organisations, especially those that go beyond single diagnoses, should be actively engaged in the co-design and co-production of acceptable and effective services.

Change offers the opportunity for meaningful measurement and evidence-based decision-making, as highlighted by the UK ADHD Taskforce report. ¹ The economic case is powerful: symptom improvement with ADHD medication demonstrates a ‘number-needed-to-treat’ of three, i.e. it is one of the most effective interventions across medicine. The wider benefits are considerable. ^{1,Reference Zhang, Zhu, Sjölander, Nourredine, Li and Garcia-Argibay2} A compelling rationale emerges for reconfiguring primary care and psychiatry, with neurodivergence as a key component of core practice and ‘stepped care’. Neurodevelopmental expertise needs to be embedded within training, clinical pathways and service organisation. Building on National Health Service England’s model of autism training, prescribed via the Health and Social Care Act (2022), we call for mandatory training in neurodivergence across the public sector. Routine screening must become standard, integrated care should replace silos and policy must allocate resources to ensure parity between ‘preventative and supportive’ neurodevelopmental provision and ‘reactive’ acute psychiatric care. This shift necessitates giving neurodivergent individuals better access to psychosocial and occupational activities that many of us take for granted. We can reduce crises, and thus the harms and restrictions inherent in acute care, while enabling people to develop activities that are meaningful for them and their communities. Good examples of transdiagnostic neurodevelopmental provision already exist within areas of paediatric and mental health clinical services. Further integration in psychiatric practice across the lifespan will optimise care. Neurodevelopmental formulation should be part of all psychiatric practice, motivated by increasing evidence that timely recognition, leading to early social, educational and occupational support, mitigates risk. For co-occurring mental illness, tailoring interventions can enhance clinical outcomes. We recognise that the psychiatrist’s role may concentrate on those neurodivergent individuals with most disability, risk and/or occurring severe mental illness. Such prioritisation should, nevertheless, cohere with initiatives (for prevention and support) across other sectors, with psychiatry retaining a guiding influence.

Research continues to refine understanding of individual and population needs, mechanistic overlaps and effective interventions. Importantly, the data are already at hand to justify decisive action. Under-recognition carries a heavy toll in avoidable morbidity, carer burden and lost lives. Systematic identification and intervention can dramatically improve outcomes and reduce societal and economic costs.

Blueprint for the future

The report of the Independent ADHD Taskforce (UK) provides a welcome blueprint for systemic transformation. This must be extended to the transdiagnostic expression of neurodivergence: The structuring of national, regional and local service provision for neurodivergent children and adults across sectors (government departments, health, education, employment and the criminal justice system) requires better recognition of diverse, overlapping and interacting neurodevelopmental traits. Upstream strategies for identification, prevention and early support must be combined with downstream cross-sector changes in commissioning of services, and co-designed and co-produced with neurodivergent individuals, families and carers, to ensure acceptability and efficacy.

Child and adolescent psychiatry teams, working with paediatricians and other medical professionals, can shape evidence-based early-years, school-age and social interventions to mitigate the heightened risks of mental illness associated with neurodivergence. For young adults, a neurodivergent lens can powerfully direct early interventions for mental illness. Across their lifespan, acknowledging the fact that neurodivergence is common and lifelong will improve and tailor effective care offered across diverse mental health services. Psychiatrists should help lead initiatives to ensure that neurodivergent individuals are also not disadvantaged in their receipt of physical healthcare: integrated mental and physical care is often implemented within paediatrics, intellectual disability services, perinatal, liaison, old-age and addiction psychiatry. Pilot schemes indicate the value of similar models within specialist neurodevelopmental services. Correspondingly, the training and credentialling of clinicians in developmental neurodivergence should extend across medical disciplines. However, psychiatrists arguably remain best placed to offer careful biopsychosocial formulations of health that integrate updated knowledge of neurodivergence. Neurodivergence represents a large part of the psychiatric caseload of highly experienced generalists who, perhaps, do not yet fully realise this. We hope that every psychiatrist might understand their existing patients better by including a neurodevelopmental perspective to help tailor existing approaches in enhancing individual patient care.

Psychiatry, as a whole, faces a choice: to continue to ignore the elephant in the room or to embrace proactive, integrated, neurodevelopmentally informed, personalised care. The latter promises to improve individual outcomes and deliver collective gains in public health, social equity and economic sustainability. To achieve these goals, all psychiatrists, in whatever area they work, should be confident in recognising and understanding neurodivergence. Diagnosis is not a specialist task, but a duty for every psychiatrist.