The Comorbidity Blind Spot: Why Children with ADHD or Autism Need More Than a Neurodevelopmental Assessment
A neurodevelopmental assessment can bring profound clarity. It may finally explain executive dysfunction, sensory processing differences, attention regulation, communication patterns, impulsivity, or the exhausting daily work of masking.
An ADHD or autism diagnosis should not, however, become a full stop.
Sometimes a child’s anxiety, low mood, obsessive fears or behavioural changes are quietly folded into the neurodevelopmental profile. The distress becomes “part of the ADHD” or “just the autism”, and a co-occurring mental-health difficulty goes unseen.
Clinicians have a name for this. It is called diagnostic overshadowing: the tendency for one prominent diagnosis to absorb everything else a person is experiencing. In children, it is the comorbidity blind spot.
What did the 2026 umbrella review find?
Fortnum and colleagues (2026) brought together 33 systematic reviews, covering 113 primary studies and 14,608 children and adolescents aged 3 to 18. The reviews spanned children with ADHD, autism, intellectual disability and specific learning disorders.
Two points about those numbers matter before we go further.
First, an umbrella review is a review of reviews. The same primary studies, and therefore the same children, can appear in more than one of the underlying reviews. The total should be read as the volume of evidence synthesised, not as 14,608 individually counted children.
Second, the diagnostic groups are not sealed compartments. Many autistic children also have ADHD. A significant proportion of children with intellectual disability are autistic. Children appear in more than one column, and any single child may sit in several at once.
With those caveats in place, the review examined co-occurring psychiatric disorders and symptoms, including depressive, anxiety, fear-related, obsessive-compulsive and behavioural difficulties.
Pooled current prevalence estimates varied considerably across groups and outcomes:
Depressive disorders: roughly 3% to 14%
Anxiety disorders: roughly 1% to 49%
Behavioural disorders: roughly 3% to 47%
Where comparisons with non-neurodivergent children were available, the odds of a co-occurring psychiatric difficulty were consistently and often substantially higher, with the largest effects at the upper end of a wide range.
Those ranges are wide for a reason. The underlying studies used different samples, different diagnostic definitions, different measurement tools and different standards of methodological quality. “Current prevalence” also means point prevalence, not lifetime experience.
So these are population-level associations, not predictions about any individual child. They do not show that ADHD, autism or another neurodevelopmental condition causes mental illness. What they show is that co-occurring difficulty is common enough that it should be actively looked for rather than assumed away.
The clinical message is more nuanced than a headline figure:
A neurodevelopmental explanation may be entirely accurate and still incomplete.
Three overlapping explanations
A child’s difficulty may arise from their neurodevelopmental profile, from a co-occurring mental-health condition, from an environmental mismatch, or from all three at once.
These categories are not mutually exclusive, and treating them as a multiple-choice question is how children get missed. A child with ADHD may have genuine executive-function difficulties, become overwhelmed by repeated school sanctions, and then develop anticipatory anxiety about attending at all.
The behaviour is real. The causes are layered.
Core traits, or co-occurring distress?
No single sign settles it. We look for patterns, changes and context.
A core neurodevelopmental trait tends to be longstanding, although its impact often becomes more visible when demands increase, typically at transitions. A co-occurring mental-health difficulty more often appears as a change from that child’s baseline, a marked escalation, or a new decline in functioning.
Possible signals include:
A sudden or sustained change in sleep, appetite or energy
Increased physical complaints such as headaches or stomach pain, without assuming these are attention-seeking
Reluctance to attend school, college or usual activities
Social withdrawal beyond the child’s typical and healthy need for solitude
Loss of interest in something that previously mattered to them
Persistent fears, checking, reassurance-seeking or intrusive thoughts
More frequent emotional shutdowns, meltdowns or outbursts
A noticeable decline in attendance, learning, self-care or relationships
One signal is different from the rest. If a child expresses hopelessness or worthlessness, says that life is not worth living, or indicates any intention to harm themselves, that is not an observation to monitor over half a term. Contact the GP the same day, or use the urgent routes listed at the end of this article.
None of the other signs diagnose depression or anxiety. They indicate that the child deserves a broader conversation.
Communication differences make internal distress harder to read. Some children describe anxiety through body sensations, anger, avoidance, or “I don’t know”. Others mask at school and release everything at home, which produces a misleading picture of where the problem is located and, too often, a misleading picture of who is causing it.
Why assessment must look beyond the label
A compassionate assessment is not a checklist of symptoms. It considers the child’s developmental level, communication style, sensory needs, masking, relationships and environment.
A clinician may need to explore:
Baseline. What was this child like before the current difficulty?
Timeline. When did the change begin, and what else was happening then?
Context. Does it occur at home, at school, socially, or across all settings?
Communication. How does this child show fear, sadness, overload or confusion?
Physical health. Could pain, sleep disruption, medication effects or another health issue be contributing?
Masking. Is the child appearing outwardly capable while running on empty?
Function. What has changed in attendance, relationships, learning, eating, sleep or self-care?
Environment. Are demands, sensory conditions or social expectations exceeding this child’s available capacity?
This is why multidisciplinary assessment matters. Parents, teachers, SENCOs, GPs, psychologists and mental-health professionals each hold a different part of the picture, and none of them holds all of it.
School staff do not diagnose mental-health conditions. They can, however, notice changes, document patterns, provide reasonable adjustments, and bring the SENCO and family into the conversation early.
A practical questions checklist
Parents, schools and clinicians can use these to move from vague concern to useful observation:
What has changed, specifically?
When did the change start?
Is the child sleeping differently?
Has attendance or punctuality altered?
Are physical complaints increasing?
Has the child stopped enjoying something that previously mattered?
Are they avoiding particular lessons, people, places or sensations?
What happens immediately before and after an outburst, shutdown or refusal?
Does the child seem frightened, sad, ashamed, overwhelmed or exhausted?
What adjustments have already been tried?
Did any adjustment reduce distress, even briefly?
What does the child say is happening, in their own communication system?
Is there any immediate concern about safety?
The purpose is not to interrogate the child. It is to build a shared and compassionate map.
Name, Normalise, Redirect: a gentle response framework
The Name–Normalise–Redirect framework is my own work. It is not an established treatment protocol and it is not a substitute for clinical assessment. It is a communication tool that helps adults respond without shame or premature conclusions.
Name. Describe what you notice, without blame. “I’ve noticed that mornings have become much harder, and your stomach has been hurting more often.”
Normalise. Validate the nervous system’s response without dismissing the problem. “When school feels unpredictable or overwhelming, the body can respond with fear, pain, shutdown or anger. That does not mean you are being difficult.”
Redirect. Move towards support and curiosity. “Let’s work out what is making mornings feel unsafe, and who can help us.”
The redirect might mean speaking to the GP, contacting the school SENCO, requesting a meeting about SEN Support, or asking a mental-health professional for a broader assessment.
The emphasis is on consistency rather than intensity. One dramatic conversation rarely reveals the whole picture. Small observations, repeated calmly over weeks, produce a far more reliable clinical signal.
What support may look like
The pathways below describe England. Scotland uses Additional Support Needs and a Co-ordinated Support Plan, and Wales uses Additional Learning Needs and an Individual Development Plan, so the terminology will differ if you are outside England.
If you are concerned about a child:
Speak to your GP about changes in mood, anxiety, sleep, physical symptoms or functioning.
Where appropriate, ask about referral to CAMHS or your local children’s mental-health service, which may operate under a different name.
Contact the school’s SENCO to discuss your observations, reasonable adjustments, and whether SEN Support is appropriate.
If needs are complex and long-lasting, ask the local authority about an Education, Health and Care needs assessment, and whether an EHC plan may be relevant.
Consider whether the child needs a genuinely multidisciplinary assessment, rather than several professionals working separately with disconnected information.
Keep the conversation focused on the child’s needs, rather than on proving whether a behaviour is “caused by” ADHD or autism.
Support should not have to wait until a child reaches crisis point.
That principle does not require blanket screening on a fixed schedule for every child. Assessment should be proportionate, responsive, and triggered by changes in presentation, risk and functional impact.
A note about urgent safety
If a child or young person is in immediate danger, seriously injured, or at imminent risk of harming themselves or someone else, call 999 or go to A&E.
For urgent mental-health help in England, contact NHS 111 and select option 2. The Samaritans can be reached on 116 123 at any hour. Parents and carers can contact the YoungMinds Parents Helpline on 0808 802 5544.
Compassionate Final Note
Your child is not a diagnosis, a behaviour chart, or a problem to be managed into silence.
ADHD and autism explain a great deal about how a child experiences the world. They do not invalidate anxiety, depression, fear, exhaustion or grief. Nor should a child have to become visibly unwell before the adults around them take their inner experience seriously.
The most useful question is rarely “which label explains this?”
It is:
“What has changed, what might this child be communicating, and what support would make life more workable?”
With careful listening, environmental understanding and timely professional help, the comorbidity blind spot can become an opportunity for fuller recognition, and for more compassionate care.
Educational disclaimer
This article is for educational information only. It does not provide a diagnosis, does not constitute individual medical or psychological advice, and does not replace assessment by an appropriately qualified professional. If you are concerned about a child’s health, safety or functioning, contact your GP, the child’s school, or an appropriate mental-health service.
References
Department for Education, & Department of Health. (2015). Special educational needs and disability code of practice: 0 to 25 years. https://www.gov.uk/government/publications/send-code-of-practice-0-to-25
Fortnum, K., Erskine, N., Cairney, J., Kwan, M. Y. W., & Bourke, M. (2026). Review: Co-occurring psychiatric disorders and symptomatology among children and adolescents with neurodevelopmental disorders: An umbrella review with individual study meta-analysis. Child and Adolescent Mental Health. Advance online publication. https://doi.org/10.1111/camh.70093
National Institute for Health and Care Excellence. (2013). Autism spectrum disorder in under 19s: Support and management (NICE Guideline CG170). https://www.nice.org.uk/guidance/cg170
National Institute for Health and Care Excellence. (2019). Attention deficit hyperactivity disorder: Diagnosis and management (NICE Guideline NG87). https://www.nice.org.uk/guidance/ng87
Further study information: PubMed, PMID 42047642.
Website: lifechanges4good.com | Email: dr.danielle@lifechanges4good.com
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