What do we already know?

Attention-deficit/hyperactivity disorder (ADHD) was originally described among children and adolescents but is now recognized in the adult population as well

  • ADHD is a psychiatric condition characterized by excessive inattention, hyperactivity, or impulsivity, either alone or in combination

Research with children and adolescents suggests there may be a link between traumatic brain injury (TBI) and ADHD

  • One study found that youth with ADHD who sustained a TBI had more difficulty with daily activities and more behavioural problems compared to those without ADHD
  • TBI and ADHD have overlapping symptoms such as memory and attention difficulties, executive dysfunction, and impulsivity

ADHD may be both a potential risk factor and consequence of TBI


What did they want to know?

The goal of the study was to describe the association between lifetime TBI and ADHD in a population sample of adults.


What did they do?

Telephone survey of 3993 adults across Ontario, Canada (part of a larger study)

Lifetime diagnosis of TBI

  • Asked about history of traumatic brain injury

Positive screen for current ADHD

  • Adult ADHD Self-Report Scale-V1.1 (questionnaire of ADHD symptoms)

Lifetime diagnosis of ADHD

  • Diagnosis of ADHD by health care professional


What did they find?

17.1% of participants had a history of TBI

For the entire sample: 3.4% positive for current ADHD, 2.5% had diagnosed lifetime ADHD

  • For those with TBI history: 6.6% positive for current ADHD, 5.9% had diagnosed lifetime ADHD
  • This means the prevalence of ADHD is around 2x greater in adults with TBI compared to those without TBI

Those who sustained a TBI had greater odds of also screening positively for current ADHD and of reporting a lifetime diagnosis

  • For those with TBI, the odds of screening positively for current ADHD were greater for those aged 18-29 and 50+
  • There was no difference among age groups for lifetime diagnosis of ADHD


What does this mean?

Among adults with brain injury, a significant proportion screen positive for ADHD and have a history of ADHD

TBI history should be assessed during screening and assessment of ADHD in adults

  • It is possible that adults with ADHD are more likely to engage in risky behaviours that could worsen any problems they experience post-TBI

Since this was a cross-sectional study (i.e., conducted at 1 point in time), we can’t determine causation (i.e., whether ADHD increases risk of TBI, TBI increases risk of ADHD, or both)

  • Studies following participants over a long period (i.e., longitudinal studies) should be conducted to determine causation and to further describe the connection between TBI and ADHD at different ages



Ilie, G., Vingilis, E. R., Mann, R. E., Hamilton, H., Toplak, M., Adlaf, E. M., … & Cusimano, M. D. (2015). The association between traumatic brain injury and ADHD in a Canadian adult sample. Journal of Psychiatric Research69, 174-179.


We summarize a recently published research study every week to give you current, evidence-based brain injury information.


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