Attention-deficit hyperactivity disorder (ADHD) is a neurobiological disorder characterised by symptoms of hyperactivity, inattention, and impulsivity. People with the condition are often prescribed a stimulant drug called methylphenidate, which treats these symptoms. However, scientists do not fully understand how the drug works.
Now, researchers at the Okinawa Institute of Science and Technology Graduate University (OIST) have identified how certain areas of the human brain respond to methylphenidate. This work may assist researchers to understand the precise mechanism of the drug and ultimately develop more targeted medicines for the condition. Previous research suggests that people with ADHD have different brain responses when anticipating and receiving rewards, compared to individuals without ADHD. Scientists at OIST have proposed that in those with ADHD, neurons in the brain release less dopamine – a ‘feel-good’ neurotransmitter involved in reward-motivated behaviour – when a reward is expected, with dopamine neurons firing more when a reward is given (https://www.healthline.co./health/adhd#:~:text=attention deficit hyperactivity disorder (ADHA, and children can haveADHA0).
A new study reports that the risk of being involved in car crashes increases for those diagnosed with attention-deficit/hyperactivity disorder (ADHD). The study in the Journal of the American Academy of Child and Adolescent Psychiatry (JAACAP), published by Elsevier, looked specifically at the rate of car crashes by adulthood, which was 1.45 times higher in those with a childhood history of ADHD compared to adults with no ADHD.
According to research fellows at the Royal’s Institute of Mental Health Research, University of Ottawa, ADHD is a common neurodevelopmental disorder. Between 5 percent and 75 percent of children with ADHD can continue to have the disorder into adulthood. Extant research shows that ADHD is associated with more traffic violations, speeding violations, license suspensions, and risky driving behaviours.
The likelihood of risky driving behaviour increases with persistence of childhood ADHD symptoms into adulthood. Prior research from our group as well as by others also shows that, aside from driving behaviours, a persistence of ADHD into adulthood can impair functioning in other domains. These domains can include occupational performance, educational attainment, emotional functioning, substance use, and justice involvement.
The findings, based on the Multimodal Treatment Study of ADHD, a multisite study with six centres in the United States and one in Canada. The MTA is one of the largest studies on treatment strategies for ADHD and includes a follow-up arm spanning 16 years.
A cohort of 441 children with ADHD and 231 age- and sex-matched comparison children without ADHD from the same classrooms were studied between the ages of 7 and 25 years.
The researchers tracked data on ADHD symptoms, driving outcomes as well as a number of comorbid conditions, such as oppositional defiant disorder, conduct disorder, antisocial personality disorder, and substance use during childhood and into adulthood.
The researchers found that rates of licensure and ages at licensure were comparable between adults with and without a history of ADHD. However, the two groups differed in rates of car crash involvement by adulthood. Importantly, adults with continuing ADHD symptoms had the highest rate of car crash involvement compared to adults with no history of ADHD (1.81 times higher). Finally, rates of car crashes did not differ between adults whose ADHD symptoms remitted and adults who never had any ADHD.
Clinicians must keep in mind the long-term effects of childhood ADHD on quality of life while attending to patients and take a holistic approach to treatment and management (Roy, Garner, Epstein, Hoza, Nichols, Brooke, James, Swanson, Arnold, and Hechtman. Effects of Childhood and Adult Persistent Attention-Deficit/Hyperactivity Disorder on Risk of Motor Vehicle Crashes: Results from the Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder. Journal of the American Academy of Child & Adolescent Psychiatry, 2020; 59 (8): 952 DOI: 10.1016/j.jaac.2019.08.007).
