ADHD: Co-occurring Conditions
ADHD rarely comes alone. Understanding common co-occurring conditions helps ensure your child gets comprehensive support, not just partial treatment.
of people with ADHD have at least one co-occurring condition
have two or more co-occurring conditions
higher risk of anxiety and depression compared to general population
of autistic individuals also meet criteria for ADHD
When ADHD co-occurs with other conditions, several things can happen:
- One condition may mask another (anxiety can look like inattention)
- One may be diagnosed while the other is missed
- Treatment for one may not address symptoms from the other
- Strategies that help one may worsen the other
This is why comprehensive assessment is important, and why treatment plans should consider the whole picture - not just the primary diagnosis.
Common co-occurring conditions
Anxiety co-occurs with ADHD in up to half of cases. It may be a separate condition or develop as a consequence of repeated failures, criticism, and unpredictability.
Signs to watch for:
- •Excessive worry about school, performance, or social situations
- •Physical symptoms: stomach aches, headaches, difficulty sleeping
- •Avoidance of anxiety-provoking situations
- •Perfectionism or fear of making mistakes
- •Need for reassurance
Clinical distinction:
Anxiety can look like inattention (mind elsewhere worrying) or be masked by ADHD impulsivity. Both may need to be addressed for either to improve.
ADHD and autism co-occur much more frequently than chance would predict. Until 2013, diagnostic guidelines prevented dual diagnosis, leading to many missed cases.
Signs to watch for:
- •Social communication differences beyond impulsivity
- •Restricted interests or repetitive behaviours
- •Sensory sensitivities or seeking
- •Strong preference for routine and predictability
- •Literal understanding of language
Clinical distinction:
Both conditions affect attention and social functioning, but the mechanisms differ. See our Overlaps module for detailed comparison.
Dyslexia, dyscalculia, and dysgraphia are all more common in children with ADHD. These are distinct from the academic impact of ADHD itself.
Signs to watch for:
- •Reading difficulties despite adequate instruction and intelligence
- •Significant maths difficulties beyond working memory impact
- •Handwriting or motor coordination problems
- •Persistent spelling difficulties
- •Discrepancy between verbal ability and written work
Clinical distinction:
ADHD affects academic performance through attention, memory, and organisation. Learning difficulties affect the acquisition of specific skills. Both may be present.
Sleep problems are extremely common in ADHD and can worsen daytime symptoms significantly. Difficulty falling asleep, restless sleep, and difficulty waking are typical.
Signs to watch for:
- •Difficulty settling at bedtime (racing mind)
- •Delayed sleep onset
- •Restless sleep or frequent waking
- •Difficulty waking in the morning
- •Excessive daytime tiredness
Clinical distinction:
Poor sleep can cause ADHD-like symptoms. Always consider whether sleep deprivation is contributing. Some ADHD medications can also affect sleep.
ODD involves a pattern of angry, defiant behaviour toward authority figures. In ADHD, this often develops as a consequence of repeated criticism and frustrated relationships.
Signs to watch for:
- •Frequent arguments with adults
- •Actively defies or refuses requests
- •Deliberately annoys others
- •Blames others for mistakes
- •Easily annoyed; loses temper frequently
Clinical distinction:
Some "defiance" in ADHD is actually the result of forgetting instructions, impulsivity, or frustration - not wilful disobedience. Consider whether the behaviour serves a function.
Depression risk increases with age, particularly if ADHD goes untreated or unsupported. Years of criticism, failure, and social difficulties take their toll.
Signs to watch for:
- •Persistent sad or irritable mood
- •Loss of interest in previously enjoyed activities
- •Changes in appetite or sleep
- •Fatigue, low energy
- •Feelings of worthlessness or excessive guilt
Clinical distinction:
ADHD motivation difficulties can look like depression. Key difference: in depression, nothing feels enjoyable; in ADHD, enjoyable things still capture attention.
Quality assessment for ADHD should always screen for co-occurring conditions. Questions to ask your clinician:
- Have you screened for anxiety and depression?
- Have you considered whether autistic traits are present?
- Should we assess for specific learning difficulties?
- Have sleep problems been explored?
- How will co-occurring conditions affect the treatment plan?
If your child was assessed and you feel something was missed, you have the right to seek further evaluation.
When multiple conditions are present, treatment needs to be thoughtful:
ADHD + Anxiety
- • Address whichever causes most impairment first
- • Some ADHD medications can increase anxiety initially
- • CBT may need adapting for ADHD attention difficulties
ADHD + Autism
- • Both sets of needs require attention
- • Medication may help ADHD symptoms in autistic children
- • Environmental adjustments should consider both
ADHD + Learning Difficulties
- • May need both ADHD support and specific learning intervention
- • ADHD treatment alone won't fix learning difficulties
- • School accommodations should address both
ADHD + Sleep Problems
- • Addressing sleep can significantly improve ADHD symptoms
- • Some ADHD medications affect sleep timing
- • Sleep hygiene is foundational but often insufficient