Recent global prevalence estimates suggest approximately 3% of adults have ADHD, but rates vary significantly by country and methods of case identification. Changes in diagnostic thresholds, missed diagnoses in childhood, and increased awareness by clinicians and the general public, all make identifying the “true” prevalence of ADHD a challenge. This is reflected in the rapid rise in new diagnoses made in the UK in adulthood: from 2000 until 2018 diagnoses increased 20-fold in men and 15-fold in women respectively. There was a similar 21 fold rate in Japan, and an increased diagnosis rate in the USA, with higher rates in younger lives.

In childhood there has been a less dramatic rise in diagnoses. Majority clinical opinion is that there remains a high risk of non-diagnosis or missed-diagnosis in adults.

Diagnostic challenges in core symptoms of ADHD in adulthood include inattention symptoms and/or hyperactivity-impulsivity symptoms*. Crucially these symptoms should be sustained and present across different domains (i.e., work and home life) and not better explained by another diagnosis. The process of diagnosis of ADHD in adults should include a full psychiatric assessment, completion of standardised symptom checklists and questionnaires, an ADHD specific diagnostic interview and information from informants, such as family members or partners.

People with ADHD are frequently diagnosed with other mental and physical health conditions. This can make it difficult to recognise underlying ADHD. Hyperactive and impulsive symptoms tend to be more common in childhood and become less of a challenge over time, so they may be less prominent in adults who receive a new diagnosis. Inattentive symptoms tend to become more of an issue in teenage years and adulthood. Under-diagnosis and misdiagnosis is more common in women and minoritised ethnic groups. 

Waiting times for adult ADHD diagnostic assessments in the UK National Health Service (NHS) have skyrocketed, due to increased demand. However, there is huge regional variation in waiting times. In 2023, waiting lists varied from three months to a predicted five to ten years , with the Trust in the latter case closing its doors to adult referrals in October 2024. This delay has led to some providers introducing referral screening, this is despite all referrals having to come through the patients General Practitioner and there being no agreed system for screening in the UK. Around a third of referrals are rejected at screening and patients do not have a right to a second opinion in the NHS, so this effectively prevents people from being able to get an NHS assessment. Women are more likely to be rejected before a full assessment, despite guidelines clearly stating they are under-diagnosed.

These hurdles mean that patients who do receive a diagnosis in NHS clinics have had very comprehensive assessments and are unlikely to have been misdiagnosed. Long waiting lists mean that many patients resort to private assessments. These can be of varying quality, with much of the variance explained by the healthcare professional completing the assessment. General Practitioners may be restricted in their desire or ability to prescribe medication for ADHD on the basis of these private assessments. As such, if prescribed medication is recommended, individuals will have to pay privately for this medication long-term. This further increases the inequalities experienced by adults with ADHD.

In the USA, access to diagnosis depends on location, insurance coverage and affordability. Insurance may not cover full neuropsychological testing and so we saw an expansion in the number of telehealth or virtual services, with an estimated 50-70% of assessments now coming via private providers. Rising diagnosis rates in adults in this context have led to suggestion of lowered diagnostic thresholds, with private screenings yielding 2-3 fold higher rates of diagnosis than in public or insurance-based US providers.

In Asia factors affecting diagnosis rates span cultural, systemic, educational and healthcare domains. Diagnostic tools and standardised assessments for adult ADHD are not consistently and widely adapted for local languages and cultural contexts. Neurodevelopmental disorder is recognised under ICD classification however, and adult ADHD assessments are increasingly available via private healthcare providers, including on-line virtual clinics.

Treatment for ADHD in childhood often includes a combination of medication, psychotherapy, behaviour management strategies, and educational accommodations or interventions. Medications such as stimulants are often effective in managing ADHD symptoms, but they must be used under the supervision of a healthcare provider due to potential side effects. Psychotherapy, including cognitive-behavioural therapy, can help individuals with ADHD learn to manage their symptoms and cope with the disorder. Behavioural management strategies can also help reduce problematic behaviours and increase desired behaviours. Education interventions can help students with ADHD succeed academically by offering extra support, accommodations, or specialized education plans.

In adulthood, medication is the most common form of treatment, but only 11% of those with an ADHD diagnosis in the UK take medication regularly.

Most commonly this would be methylphenidate (e.g.Ritalin, Concerta, Medikinet), but lisdexamfetamine (e.g. Vyanse, Elvanse) is becoming more frequent, as it is licenced for treatment initiation in newly diagnosed adults. In the UK, the proportion of adults prescribed ADHD medication has increased as the incidence has increased. Young adults are treated most commonly and this is the group where medication prescribing is increasing most rapidly.

The CDC reported higher levels of medication prescribing in the USA in 2023, with 33% of adult ADHD patients using stimulant medications, and 5.9% non-stimulant, alongside a similar offering of psychotherapy and lifestyle options as per above. In Asia the rates of medication in the adult group are much lower, with the Lancet and JAMA reporting less than 10% of patients receiving medication, and an estimated sub 1% prescribing of stimulant medications due to restrictions in prescribing. Psychotherapy can also be useful for an adult receiving a new ADHD diagnosis. Often adults will have made life choices, such as choice of work roles, that best suit their ADHD symptoms, even before a diagnosis is made. 

Receiving a diagnosis of ADHD in adulthood often has a positive impact. This may be through better self-awareness and understanding, improved functioning, and identification of unique strengths. Challenges come with stigma, disclosure to friends, family and employers. Some individuals may experience grief or anger about missed opportunities. Many adults with ADHD report struggling throughout life with a sense of underachievement and failure to realise their full potential. It is common for individuals to develop compensatory strategies that prove effective in mitigating psychosocial disruption but paradoxically mask the presence of ADHD symptoms. Often, these adults seek mental health treatment due to depression or anxiety secondary to ADHD-related psychosocial struggles.

Interestingly, some adults present for evaluation of ADHD after their own children have gone through assessment for possible ADHD and they realise that they themselves have endured lifelong struggles with similar symptomatology. However, earlier diagnosis often leads to better outcomes as there is more opportunity for intervention and reduced likelihood of developing comorbid mental and physical health problems.

As young people grow up, they may experience more challenges and receive less support for their ADHD. For example, if someone has lived at home and had lots of support, their ADHD might not cause them problems until they move out of home. Young adults with ADHD can find life adjustments challenging, these include starting work or further education, living independently, beginning and sustain relationships and managing finances.

Throughout life, new challenges, like parenthood or a new job role, might further increase an individual’s overall level of stress. This can mean that their ADHD causes more challenges as they get older. As the overall level of demand and stress increases, people with ADHD are more likely to struggle to keep up. This may explain a rise in late diagnoses of ADHD.

An example of this sudden deterioration in functioning is that many people reported issues in handling changes in their work during the COVID-19 pandemic. The move to home working, and the return to offices that followed, contributed to increases in diagnoses. This period also saw a doubling in the rate of prescriptions for ADHD medication, suggesting individuals with pre-existing diagnoses increased their use of medication as a way of managing their symptoms.

Surveys of adults with ADHD report that the majority have lost or left a job because of issues related to their ADHD. Elements of conventional jobs, such as self-organisation or sustained attention may be particular challenges. Much as there is variation in symptoms of ADHD, there is variation in the types of work that will suit adults with ADHD. Often roles that require creative thought, urgency and deadlines, risk-taking and bursts of activity will suit adults with ADHD. Adults with ADHD may self-select into jobs that provide this kind of stimuli. However, as they become more senior, roles may entail less satisfying elements and they may struggle to adapt.

Adults with ADHD are at increased risk of other mental and physical health conditions. These include: anxiety, depression, bipolar disorder, substance use disorders, obesity, disordered eating, allergies, asthma, sleep disorders, and diabetes. Some of these conditions may be as a result of living with ADHD, such as anxiety and depression, or attempts to self-treat symptoms, such as substance use disorders. Studies have indicated that adults with diagnosed ADHD have an increased risk of premature death, with some estimates equating this risk to a reduction in life expectancy of up to 7 years compared to the general population.

Much of this premature mortality is due to risk taking behaviour, accidental injury and suicide, often related to psychiatric comorbidity. People with ADHD who receive medication appear to have a lower risk of premature mortality, but this does not reduce the risk to general population levels, particularly if psychiatric disorders co-exist. A 2024 JAMA observational trial analysis looked to understand this further, finding all-cause mortality lower in the medicated versus non-medicated group (HR 0.79) predominantly due to fewer unnatural deaths from suicide or accidental poisoning. Concerns from earlier studies, that suggested increased cardiovascular risk on stimulant therapy, were largely allayed with a reduced risk of death by natural causes (which includes deaths due to cardiovascular disease) in females and no statistically significant increase in the male group. The use of stimulant medication may also improve outcomes due to a reduced rate of cigarette smoking, as per Schoenfelder et al ₂₀₁₄.

Impacts of ADHD on mortality and morbidity come from a diverse group of illnesses; from anxiety and depression, bipolar disorder, substance use, eating disorder, obesity, diabetes, sleep disorders and atopy. Our underwriting experts can provide more granular details.

It is hoped that there will be better outcomes for children and adults with ADHD as awareness of ADHD and acceptance of neurodiversity grows. However, as it currently stands the evidence suggests ADHD should be treated as a medical disorder, in that it leads to disadvantage, distress and disability. Care should be taken to understand how and when the diagnosis was made and the specific challenges of the individual. Careful consideration of comorbid physical and mental health diagnoses and how these may interact with the ADHD diagnosis to impact future outcomes is vital. Adaptations to job roles, in collaboration with the individual, may help support fulfilling employment and avoid sequelae of ADHD.

Life & Health Insurance considerations – Underwriting of ADHD

From an underwriting perspective the ability to assess risk comes first from asking appropriate questions at application stage, formulated so as to consider the spectrum of impacts, likelihood of future claim and reduce any perception of stigmatisation in the applicant. Once you have the information needed to make a decision, as for any medical topic, the underwriting outcome ideally is communicated to the customer with some explanation as to why any rating or exclusion applies. Understandably the clinical focus will be one looking to the positives, rather than considering the more negative possible outcomes for this, or indeed any, patient group.

Insurance considerations – Claims

Our medical officer teams have seen an increase in requests for assistance to help navigate disability claims with ADHD as part of the presentation. Sometimes it is obvious that a new diagnosis in the claimant, or indeed a child and parent simultaneously, brings complexity to the claims process. Sometimes it is clear that coping strategies that have compensated for many years successfully may fail during life events that are particularly onerous. For all these cases the usual bio-psycho-social (BPS) philosophy applies, looking to holistically assess sensitively the functional impacts, the appropriateness and timing of interventions and the claimant's engagement with the recovery process. Seeking appropriate expert commentary can yield helpful results.