adhd in canada: stats, diagnosis and living with the condition

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adhd affects five to nine per cent of canadian children and three to five per cent of canadian adults.

by robin roberts

published apr 10, 2024

last updated feb 19, 2025

10 minute read

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10 minute read

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adhd affects roughly five to nine percent of canadian children. getty images

for anyone grappling with attention deficit and hyperactivity disorder (adhd), being told, “you’re just stressed out, you’ll get over it,” only exacerbates the anxiety that often comes with a diagnosis. many people who gloss over the disorder don’t realize just how serious it is.

esme fuller-thomson, professor and director of the institute for life course and aging at the university of toronto, co-authored a series of studies that showed people with adhd had shockingly high numbers of alcohol and other substance use disorders, suicide ideation, as well as sexual and childhood abuse.

what is adhd?

first documented in 1902—and having since undergone many name changes, including from minimal brain dysfunction, hyperkinetic reaction of childhood, and attention-deficit disorder with or without hyperactivity—adhd is a chronic, complex neurodevelopmental disorder that affects five to nine per cent of canadian children and three to five per cent of adults, according to the centre for adhd awareness, canada (caddac). it’s the most common neurodevelopmental disorder in children, affects both males and females (although males are diagnosed more often), and crosses all ethnic and socioeconomic backgrounds.

there are three types of adhd, which can present as mild, moderate or severe: hyperactive, inattentive, and the most common, a combination of the two.

according to the centre for addiction and mental health (camh), the hyperactive type, which is noted primarily in boys, is characterized by constant motion, restlessness, impatience, impulsivity, fidgeting, interrupting others, running or climbing excessively, or talking constantly.

people with inattentive adhd, affecting mostly girls, often have trouble paying attention, difficulty staying focused, frequently have problems with organization, are easily distracted, are often forgetful and tend to lose things.

children with adhd can also have delays in independent functioning, language, motor skills and social development, according to children and adults with attention-deficit/hyperactivity disorder (chadd). they tend to have difficulty controlling their emotions and often experience mood swings. more than two-thirds will have at least one other co-existing condition, such as oppositional defiant and conduct disorders, anxiety, depression, tic disorders or tourette syndrome. there is also a significant overlap between adhd and autism; the majority of people with autism will have adhd, says dr. doron almagor, child, adolescent and adult psychiatrist and founder of toronto’s possibilities clinic, which assesses and treats adhd.

although there is some controversy around whether or not adhd is on the rise, almagor says, “the stats we have of the actual prevalence, diagnosed adhd has stayed the same for many years. treatment rates seem to be increasing, but that could be due to increasing awareness.” according to manulife, from 2021 to 2022, the number of unique claimants for adhd medication for those aged 18 and over grew by 24.5 per cent.

he says that when he began working in the field in 1995, he was treating only children with the disorder. “we were pretty aware of childhood adhd but not that aware of adult adhd. that really became more in the public consciousness in the early 2000s and has had increased awareness even more and grew even more during the pandemic when people were facing productivity challenges working from home.”

although boys are twice as likely to be diagnosed than girls, almagor says they have the same prevalence rates; they just present differently. “you can have hyperactive girls and inattentive boys, but, just on averages, the tendency is for boys to be more hyperactive so the symptoms are more visible. girls may be suffering in silence; they may be masking their symptoms or compensating for them. treatment rates are higher in younger kids, and then as they get older, the treatment rates become the same.”

almagor says some kids are often singled out in class or ostracized when they’re not functioning at the same level as others. “they start to believe they’re stupid or lazy, which can affect their confidence and self-esteem. in fact, a lot of people with adhd are very successful.”

adhd causes and diagnosis

studies have yet to determine an exact cause of adhd, but researchers have discovered a strong genetic link. if one or both of your parents had it, you and your siblings are more likely to inherit it. other studies have shown environmental factors, such as exposure to lead or pesticides as a child, as well as childhood traumatic events, to be contributors.

contrary to some theories, adhd is not caused by watching too much television, eating too much sugar or parenting styles, but they can exacerbate symptoms for some kids. parents can learn effective strategies for raising children with adhd.

while there is a dearth of medical and mental health practitioners in general, there is also a dearth of those with adhd-specific training, primarily due to underfunding. almagor, however, says awareness among physicians is improving, and most can diagnose and treat uncomplicated adhd.

“there’s been much more education [on adhd], and more doctors are trained in the diagnosis,” says almagor, the former chair of the canadian adhd resource alliance (caddra), which provides physicians with scientifically supported guidelines for diagnosing and treating adhd. he also trains medical residents at the university of toronto in the diagnosis and treatment of adhd.

“also, more doctors are willing to diagnose or at least initiate the diagnostic process by making a referral. one has to take a history, look at other symptoms and causes that might look like adhd, then differentiate between adhd and anxiety, depression, learning disabilities and autism, as there are a lot of comorbidities between these types of disorders.”

adults can be diagnosed later in life but must have experienced some symptoms as a child; the disorder doesn’t start in adulthood. most—about two-thirds of people with adhd—continue to experience symptoms later in life, although the hyperactivity may decrease over time, according to chadd.

“adhd is considered to be a neurodevelopmental disorder, which means it’s there from childhood on. it doesn’t come and go away,” says almagor. “in some cases, it may not cause as much distress [in adulthood]. there may be coping strategies where it’s not as symptomatic until the environment changes or a person’s biology might change, such as with menopause. symptoms can also increase and decrease during a menstrual cycle because hormones have an effect.”

almagor says he’s increasingly diagnosing older adults who are undergoing a transition, either a new career or retirement, which can trigger symptoms. “often, there’s a lot of mourning because they wonder what would have happened had they been diagnosed earlier. they look back on a lifetime of employment dysfunction, substance use, marital discord, all kinds of health consequences. i tell them it’s never too late to get treatment, [but] the earlier the better.”

living with adhd

teens and young adults often struggle with new demands and stressors, such as high school and college, dealing with peer pressure, and establishing independence. for those living with adhd, these demands often lead to anxiety and depression, risky behaviour and a higher chance of substance abuse as a way to self-medicate.

fuller-thomson co-authored a study that revealed 36 per cent of young adults aged 20 to 39 with adhd had a lifetime alcohol use disorder compared to 19 per cent of their peers without adhd. cannabis use disorder among the same group with adhd was at 23 per cent compared to 10 per cent use among their peers without adhd.

“particularly striking, with other lifetime drug use disorders, [including] heavier drugs, it was almost 18 per cent versus five per cent,” says fuller-thomson. “some of them had more than one [substance abuse issue], so when you add that up, it’s almost at half in the adhd group, 49 per cent, versus 24 per cent in the no adhd group.”

adults with adhd may also experience relationship problems, trouble with consistency and responsibilities on the job, and will often procrastinate and be late for or miss appointments and meetings.

according to camh, more than three-quarters of adults living with adhd have another mental illness, such as depression, anxiety, or bipolar disorder.

adults often develop coping strategies, such as creating highly structured environments, under-reporting symptoms, or avoiding social situations that mask their condition. they also often seek out jobs that align with their symptoms (e.g., high-energy, deadline-driven, or hyper-focused types of careers) or start their own businesses so they can control their environment to accommodate their symptoms.

fuller-thomson’s research also revealed that women with adhd are eight times more likely to attempt suicide than women who do not have the disorder; men with adhd are nine per cent more likely than men who do not have adhd.

she also found that 34 per cent of women with adhd were sexually abused before they turned 18 compared to the non-adhd population of 14 per cent. among males, the numbers were 11 per cent with adhd compared to six per cent without.

as well, fuller-thomson’s research revealed that physical abuse was very high: 44 per cent of women with adhd reported being physically abused compared with 21 per cent of those without adhd; 41 per cent of men with adhd reported abuse compared to 31 per cent without.

she also found that one-third of children with adhd were physically abused or had other adverse childhood experiences. they were also more likely to be bullied.

“it does speak to health professionals being particularly cautious in screening kids with adhd because they’re vulnerable to so many of these potential negative mental health and environmental risks,” says fuller-thomson.

she says the incidence of chronic pain among those living with adhd is also very high. “more than one in four women aged 20 to 39 with adhd said that physical pain prohibited some of their activities. [pain among] their peers without adhd was nine per cent. people with adhd are also more vulnerable to accidents because of risk-taking behaviour.”

insomnia is also much more prevalent. among women, according to fuller-thomson’s studies, 44 per cent had insomnia compared to 12 per cent of their peers without adhd. smoking was also high: 41 per cent of those with adhd compared to 22 per cent of those without.

fuller-thomson goes on to say that one in three women aged 20 to 39 with adhd reported difficulty meeting basic expenses such as food, shelter and clothing due to inadequate household income, possibly due to the inability to find (or keep) employment that would accommodate their symptoms. “for their peers without adhd, 13 per cent had a shortfall.”

as for how much undiagnosed adhd costs the canadian economy in low or lost productivity, dr. gurdeep parhar, co-founder of the private adult adhd centre, says the annual cost runs between $6 to $ 11 billion due to people with adhd being less likely to be employed full-time, more likely to be fired, or not able to get along with their bosses and peers.

adhd treatment and resources

the most effective adhd therapy combines medication and counselling. the two most commonly prescribed types of drugs fall under the categories of stimulant and non-stimulant, short-acting and long-lasting. doctors will work with patients individually to find what works best for them. medications don’t cure the condition, but they can effectively control symptoms.

unfortunately, more than half of patients stop their treatment after about a year, likely from negative side effects or because they’re not responding to the medication and are reluctant to try other forms.

medication combined with non-pharmaceutical therapies, particularly modified cognitive behavioural therapy (cbt) for adhd, coaching, and mindfulness, are most effective.

“the evidence for cbt, which is a relatively short intervention—eight to 12 weeks—has shown really good outcomes to help manage adhd-related symptoms,” says fuller-thomson, who notes some provincial health plans are beginning to cover cbt.

almagor says his clinic uses multi-modal therapies, including programs that therapists can use with parents of children with adhd. “those are most helpful when you find a medication that works alongside them. the medication helps the brain to focus more, to be less hyperactive if there is hyperactivity. but you also need to learn the skills, provide the direction, for sustained effects.”

those who educate themselves about their disorder have greater insight into managing their symptoms.

maintaining a consistent schedule and routine, using notes, lists, and charts to help keep you on track and organized, can also help. accessing support groups, maintaining a healthy diet and exercise regimen, and having a strong social network can not only ease anxiety for those grappling with adhd but also help them flourish.

in fact, fuller-thomson co-authored a study in 2022 that found two in five adults who had had their adhd addressed are in excellent mental health. “this research marks a paradigm shift,” she said at the time. “most previous research, including my own, has focused on mental illness among those with adhd. so, to focus on those who are thriving mentally is refreshing and very heartening.”

for more information, resources and supports, check out caddac, caddra, camh, chadd, any of the provincial adhd clinics, or additude, a magazine specifically designed for those with the condition. good books that focus on the disorder include taking charge of adult adhd by leading expert dr. russell a. barkley, a radical guide for women with adhd by sari solden and michelle frank, and the couple’s guide to thriving with adhd by melissa orlov and nancie kohlenberger.