Key questions on ADHD and autism in adults

GPwER in neurodevelopmental differences Dr Sarah Michaels answers key questions on ADHD and autism in adults, covering aspects such as prevalence and persistence from childhood, differentiating from mental health diagnoses, supporting diagnosis with appropriate screening tools and treatment considerations. Complete the full module on Pulse 365 today.

Learning objectives

This module will support your understanding and management of ADHD and autism in adults, including to:

• Recognise the prevalence and persistence of ADHD and autism into adulthood, and understand why people may present for the first time in adulthood.
• Differentiate ADHD from mental health diagnoses, including anxiety, depression and emotionally unstable personality disorder (EUPD).
• Be aware of the licensed medications for adult ADHD, monitoring required and considerations of shared care.
• Understand masking and how to identify adults who may be autistic in primary care.
• Support neurodivergent patients on long waiting lists.

How common is ADHD in adulthood, and does it persist from childhood?

Contrary to recent headlines, adult ADHD is still likely under-diagnosed. Approximately 6% of children meet the diagnostic criteria, and over half of these continue to experience clinically significant symptoms into adulthood.^1,2 A 2023 umbrella review of global data from over 21 million participants estimated the adult prevalence at 3.1%, although this likely underestimates the true burden given how many adults have not undergone diagnostic assessment.³

ADHD is perhaps best understood as a continuous spectrum of human traits rather than a binary condition, rather like blood pressure. With current diagnostic criteria, the diagnosis reflects a threshold of trait persistence, prevalence and associated impairment in a person’s life.

ADHD is polygenic and heritable.¹ Neurodivergence does not ‘switch off’ at 18 years of age. Many adults experience impairment when external scaffolding is no longer present, such as school structure, parental oversight or predictable routine. GPs are likely to see adults presenting for the first time in their 30s, 40s or beyond.

Q2. When should GPs proactively consider ADHD? How do you distinguish it from mental health conditions such as anxiety, depression and bipolar disorder?

ADHD symptoms have historically been attributed to other issues such as anxiety, depression, or trauma. This diagnostic overshadowing is a common barrier to recognition. Consider ADHD in:

• Frequent attenders with multiple overlapping mental health presentations not responding to standard treatment.
• Women with worsening mood or cognitive symptoms around hormonal transitions (menstrual cycle, postnatal period, perimenopause).
• Adults who have recently had a major life change and are now struggling.
• High-achievers who have ‘just about coped’ but are now decompensating, such as people presenting with symptoms of burnout as they are no longer able to juggle work and family commitments.

Taking a time-line approach is helpful; ADHD traits are always present, whereas mood and anxiety disorders occur later in life, although unsupported neurodevelopmental challenges can drive secondary mental health difficulties.

ADHD vs anxiety

In ADHD, an interest-based nervous system causes distraction, rather than always worry-driven rumination. Stimulant medication is often effective even when anxiety is present, and treating anxiety alone might not resolve concentration difficulties driven by ADHD.

ADHD vs depression

Depression, often occurring later than early childhood, and involves clearly depressed mood and anhedonia, often with a hypoactive presentation. In ADHD, low mood is often reactive and intermittent, linked to rejection sensitivity or the exhaustion of sustained effort. It is present in early childhood even if it has been missed.

ADHD vs bipolar disorder

Bipolar disorder has discrete phasic episodes rather than early-childhood onset of persistent traits. Both can feature irritability, impulsivity and emotional dysregulation. A temporal approach helps distinguish the two, although co-occurrence is possible.¹

ADHD vs EUPD

EUPD is characterised by unstable self-image, fear of abandonment and persistent emptiness, which are less prominent in ADHD.

It is thought females in particular with ADHD and/or autism who mask their difficulties in childhood may be misdiagnosed with personality disorders, which could delay appropriate delay appropriate diagnosis and support.⁴

ADHD vs hormonal changes

Females with ADHD are frequently diagnosed later than males, often presenting with inattentive symptoms, masking, anxiety and low mood rather than physical hyperactivity.⁴ Oestrogen is dopaminergic, and hormonal fluctuations can worsen ADHD symptoms, with some women reporting two- to threefold increases in mood instability around menstruation and at the peri/menopause.⁴

What is the GP’s role in primary care, and which screening questionnaires are recommended?

Evidence increasingly points towards neurodevelopmental conditions being part of a wider constellation of somatic differences (rather than mental health conditions). GPs are not expected to diagnose these unless working in an extended role, although with training and primary care funding, they would be more than able to. GPs can think broadly, screen appropriately, manage co-occurring conditions and refer onwards. If there is a developmental difference that is persistent, pervasive and impairing, then referral can be considered. The services you refer to will likely specify which screeners should be used.

ADHD screening

The Adult ADHD Self-Report Scale version five (ASRS v5) is the best-validated adult ADHD screener, with sensitivity of 91.4% and specificity of 96.4%. It is brief, freely available and appropriate for primary care.⁵

Autism screening

The AQ-10 is a widely used brief autism screen in primary care but has a high false negative rate, particularly in women and those who mask.⁶ The AQ-50 is more comprehensive. The CAT-Q (Camouflaging Autistic Traits Questionnaire) identifies significant masking, and the EQ (Empathy Quotient) measures social and communication differences. These can be helpful adjunct screeners.⁶ Screening tools should never be used in isolation. A positive screen supports referral, but a negative screen does not exclude the condition.

Dr Sarah Michaels is a GPwER in neurodevelopmental differences and ADHD advanced practitioner.

Dr Michaels is co-director, secretary and educator of B4ND (British Association for Neurodiversity) and a co-director of ADHD & Autism Associates LLP.

References

1. Faraone S et al. The World Federation of ADHD International Consensus Statement: 208 evidence-based conclusions about the disorder. Neurosci Biobehav Rev 2021;128:789–818
2. You Y et al. The role of comorbid childhood mental health and neurodevelopmental conditions in the persistence of ADHD symptoms: systematic review and meta-analysis. J Child Psychol Psychiatry 2026 Feb;67(2):183-201
3. Ayano G et al. Prevalence of ADHD in Adults: An Umbrella Review of International Studies. Eur Psychiatry 2024;67(Suppl 1):S343     
4. Young S et al. Females with ADHD: an expert consensus statement. BMC Psychiatry 2020;20:404
5. Somma A et al. The Validity of the World Health Organization Adult Attention-Deficit/Hyperactivity Disorder Self-Report Screening Scale for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition in Adolescence. JCAP 2021; 31(9):631-38
6. Lai M et al. Quantifying and exploring camouflaging in men and women with autism. Autism 2016;21(6):690–702