ADHD Morbidity and Mortality over the Youth Lifespan

During the 7th Research Day at CADDRA 2020 Dr. Alain Lesage presented findings on ADHD in young people. He indicated that people with ADHD under the age of 24 experience greater physical and mental health co-morbidities, higher service utilization and increased risk of mortality compared to the general population. He highlighted the value of the Canadian and Quebec integrated chronic disease surveillance systems (QICDSS) with regards to representation and longitudinal follow-up of the ADHD population and suggested methodological ‘red flags’ in using health administrative databases to quantify the prevalence of ADHD.

Dr. Lesage reported results of a longitudinal study using the Quebec Integrated Chronic Disease Surveillance System (QICDSS), where an individual was considered to have ADHD if they had at least one physician claim or hospital discharge noted from 2000 to 2018 using ADHD diagnostic codes.

An important take away from his talk is that sensitivity analysis on outcomes derived from QICDSS indicate that ADHD can be validly identified with a small likelihood of false positives, even with a single mental health medical claim.

The study compared outcomes for those with one mental health medical claim or less during their lifetime to those with at least two claims within five years. Another comparison was between these groups to the general population without ADHD.

Results

In the US (2016 NSCH), among children 2-17 years old, 9.4% (6.1 million) had received ADHD diagnosis and 62% were taking medications. 

In Canada, the annual diagnosed prevalence of ADHD among 1-17 years old in 2011-2012 varied between 1.1% to 3.8% among provinces.1 The cumulative prevalence of ADHD reached 12.6% amongst people 24 years or younger between 2017-2018.2 Between 2000 to 2016 the incidence of ADHD in Canada increased steadily from 1% to 4%: 5.6% in boys and 3% in girls. In Ontario the diagnosed prevalence of ADHD in under 24 years old is: 5.4%.3

Young people with ADHD experience higher physical (e.g. trauma) and mental comorbidity compared to those without ADHD. The prevalence of psychiatric comorbidity – and specifically Anxio-depressive Syndrome - were significantly higher in people with ADHD.

The use of mental health medical service is varied within the sub - groups (1-11,12-17,18-24) of under 24 years old, with the later age group significantly not using any such services. This indicates a large group of untreated patients. In all, mental health specialists vs. outpatient pediatricians or family physicians are rarely (<10%) the first to diagnose ADHD in young people. 

Mortality in 18-24 diagnosed with ADHD is significantly higher in comparison to the general population. Suicide and trauma (primarily in car accidents) were closely associated with ADHD in the study .

Comparison between groups studied on three outcome indicators (morbidity, services use and mortality) showed that outcomes were similar between the group with one claim and the group with two claims or more. 

Outcomes for the comparison groups were significantly more negative compared to people without ADHD in the general population.

One of the presentation conclusions was that the single claim ADHD group may represent undertreated individuals with a higher risk of mortality.

Q&A

An interesting question suggested that the prevalence of mortality in youth population with ADHD is quite high (12.6%). Dr. Lesage was asked whether mortality in this cohort was mainly because of suicide, he answered pointing at non suicide trauma mortality in 14-18 years old - mainly due to traffic accidents; prompting campaigns against substance abuse as well as postponing driving lessons to a later age.

Another question was: Could the database help predict whether ADHD is a risk factor for COVID-19 ? Dr. Lesage suggested (theoretically) that people with ADHD are taking more risks and are less likely to obey public health instructions – thus increasing their risk for infection.

:Presenter

Dr. Lesage is a professor in the Department of Psychiatry at the University of Montreal, since 1987 Dr. Lesage was a clinician at the Montreal University Mental Health Institute and researcher at its Research Centre (formerly Fernand-Seguin Research Center).