Definition
Co-occurring conditions describes the presence of two or more conditions in the same person, common in SEND, where autism, ADHD, dyslexia, dyspraxia, anxiety, and sensory differences frequently overlap. Many UK autistic advocates and the National Autistic Society prefer "co-occurring" to the medical term "comorbid", which carries disease-of-body connotations.
In context for parents
Key checkpoints
- The presence of two or more conditions in the same person.
- Many UK autistic advocates and the National Autistic Society prefer "co-occurring" to "comorbid".
- 50–70% of autistic children also meet criteria for ADHD (Simonoff et al., 2008 and replications).
- The ESSENCE cluster (Gillberg 2010, Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations) recognises co-occurrence as the common SEND picture.
- Section B of an EHCP should name every co-occurring condition identified; omission narrows what the LA is required to provide.
The clinical evidence base on co-occurrence in SEND is now mature. The most-cited statistics: around 50–70% of autistic children also meet criteria for ADHD (Simonoff et al., 2008 and subsequent replication). Around 40% of children with ADHD have a co-occurring specific learning difficulty (dyslexia, dyscalculia, or DCD). Around 30% of autistic children have a diagnosed anxiety disorder; sub-clinical anxiety is far more common. Co-occurrence of autism, ADHD, and DCD (the "ESSENCE" cluster, Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations, Gillberg 2010) is now recognised as a more common presentation than any single neurodevelopmental condition in isolation.
The clinical and SEND practice implications matter. A child diagnosed with autism alone at age 4 may be missed for ADHD until age 9 because the autism diagnosis was treated as the explanation for all the behaviour. A child diagnosed with dyslexia at age 7 may be missed for autism until age 14 because the dyslexia diagnosis closed the case. NICE guidance (CG128, NG87) now explicitly notes that initial diagnosis should not stop further assessment where additional needs emerge.
For SEND families, the co-occurring framing has practical value. It supports asking the right next questions. "He's been diagnosed with autism, but he is also struggling with reading, could this be dyslexia?" "She has ADHD, but the motor coordination is also concerning, could this be DCD?" "He has DLD, but the social communication is also affected, could this be autism?" Each of these reframings has changed school provision and EHCP wording for many families.
In an EHCP, Section B should name every co-occurring condition identified through the assessment process. Each named condition expands the scope of need and therefore the provision in Section F. Omitting a condition from Section B narrows what the LA is required to provide.
Related terms
The terms parents most often see alongside Co-occurring Conditions.
Spiky Profile
A pattern of unusually uneven strengths and difficulties across cognitive or learning domains. Common in neurodivergent learners and often visible across WISC index scores.
Autism(ASC)
A lifelong neurodevelopmental condition that shapes how a person communicates, processes sensory information, and experiences the social world. Autism is a difference, not an illness.
ADHD
A neurodevelopmental condition affecting attention, impulse control, and activity levels. Often co-occurs with autism, dyslexia, or anxiety, and presents differently in girls and boys.
Anxiety Disorder
Persistent, intense worry or fear that interferes with daily life. In SEND, anxiety is often the driver of school avoidance, meltdowns, or shutdowns, and frequently the unmet need behind 'behaviour'.
Where parents ask about this
Parents usually find this page after one diagnosis has been made and another is suspected, or when a school is treating one diagnosis as the explanation for difficulties that may have a different driver. Searches include "co-occurring autism ADHD", "is comorbid the right word", and "second diagnosis SEND". A Beaakon paediatric specialist or independent EP can carry out a multi-disciplinary assessment that does not stop at the first diagnosis, identify the full profile, and write tribunal-grade evidence.
References
The primary legislation, statutory guidance, research, and clinical tools this page draws on.
- Simonoff, E. et al. (2008): Psychiatric Disorders in Children with Autism Spectrum Disorders
- Christopher Gillberg (2010): The ESSENCE in child psychiatry
- NICE CG128 (autism), NG87 (ADHD): explicit on further assessment when additional needs emerge
- National Autistic Society: language guidance
- Children and Families Act 2014, section 36