Attention Deficit Hyperactivity Disorder (ADHD)

ADHD is a neurodevelopmental condition that affects attention, and often activity level and impulse control as well. It begins in childhood, but it is not always recognised then, and many people are first assessed as adults. Day to day it tends to show up as tasks that never quite get started, details that get missed, and a sense of running on a motor that will not idle.

What ADHD is, and what it is not

ADHD is not laziness, low intelligence or the result of poor parenting. The Centre for Addiction and Mental Health says genetics is the most likely main cause, and that theories blaming parenting style, television or particular foods have not been supported. What the condition does affect is attention span and concentration, and often how impulsive and active a person is.

It is also not only a childhood condition. Some people mainly have difficulty with attention, some mainly with hyperactivity and impulsiveness, and some have both, and the balance can shift over a lifetime. In adults the physical restlessness often turns inward and feels more like being unable to switch off than like visible fidgeting. The Centre for ADHD Awareness, Canada reports that at least 65% of people diagnosed as children still have symptoms that affect them as adults, and estimates that ADHD affects 4% to 6% of Canadian adults.

Signs and symptoms

• Trouble holding attention on tasks that are not interesting, losing the thread of instructions, or missing details
• Being easily distracted, forgetful in daily activities, and often losing or misplacing things
• Difficulty getting organised, starting tasks, keeping track of time and finishing what you start
• Fidgeting, restlessness and difficulty staying seated, or in adults a persistent sense of being driven or unable to settle
• Talking a lot, interrupting, blurting out answers, and finding it hard to wait your turn
• Acting on impulse, including quick decisions about money, driving or work
• Emotions that arrive fast and strongly, and take longer than expected to settle again

The mix differs from person to person, and it changes with setting and with age. A quiet, inattentive child can be missed for years, while the same person may find the demands of adult life, deadlines, paperwork, bills, driving, much harder to manage than school ever was.

What raises the risk

Some risk factors cannot be changed:

• A family history of ADHD, since genetics is the most likely main cause
• Being male, since diagnosed ADHD is more common in boys than girls in Canada
• Having had ADHD as a child, since at least 65% of those diagnosed in childhood still have symptoms that affect them as adults
• Other conditions that often occur alongside ADHD, including learning disorders, anxiety and mood disorders, which can make ADHD harder to recognise

Others can often be worked on, usually with support from a health care team. These do not cause ADHD, but they can look like it or make it worse, which is why Canadian guidelines ask clinicians to review them:

• Poor or short sleep
• Alcohol and other substance use
• Untreated medical conditions and some medicines, which clinicians look for and address before settling on the diagnosis

How ADHD is diagnosed in Canada

The Canadian ADHD Resource Alliance sets out a four-step assessment used across the country. It starts with rating scales: the Adult ADHD Self-Report Scale for adults, plus a scale such as the SNAP-IV completed by someone who knows the person well and, where possible, someone who remembers their childhood. Next comes a medical review, to look for conditions and medicines that can mimic or aggravate ADHD symptoms and to go through sleep, exercise and substance use. Then there is a structured interview covering developmental history, strengths, and information from parents or close relatives, since the symptoms must have been present in childhood. Finally the clinician gives feedback and weighs the contribution of other psychiatric, psychosocial or learning factors. Assessments are carried out by family doctors, paediatricians, psychiatrists and psychologists, and for children school reports are usually part of the picture.

Treatment and day-to-day management

Clinical research for Attention Deficit Hyperactivity Disorder (ADHD) is enrolling. See the current studies ↓

Canada has its own national framework, the Canadian ADHD Practice Guidelines, published by the Canadian ADHD Resource Alliance. They describe ADHD as a long-term condition that needs regular follow-up rather than a single course of treatment, and they set out four kinds of support. Depending on age, circumstances and what is getting in the way, a health care team may discuss:

• Psychoeducation: clear information about ADHD for the person and, for a child, the family, along with written resources
• Psychosocial and behavioural approaches, including parent management training for children, cognitive behavioural therapy, coaching, and practical work on routines, organisation and sleep
• Accommodations at school and at work, which the guidelines support with template letters for educators and employers
• Medicines, which in Canada fall into non-stimulant and stimulant groups set out in the CADDRA medication chart, chosen and monitored with a prescriber
• Regular long-term follow-up, since the same symptoms play out differently at different ages and life stages

What fits one person will not fit another, and access to assessment and follow-up differs across the country. These are decisions for you and your own clinician, and this page is not a recommendation about any of them.

When to talk to a doctor

• Book an appointment with your family doctor or nurse practitioner if attention, restlessness or impulsiveness are affecting school, work, driving, money or relationships, or if a child’s teachers are raising concerns about attention or behaviour in class.
• Get a prompt assessment if attention or memory changes come on suddenly in an adult, or if a child’s behaviour or school performance changes abruptly, because other causes need to be considered, including sleep disorders, hearing or vision problems, anxiety, low mood, thyroid problems and head injury.
• Contact your prescriber promptly if someone taking ADHD medicine has new or worsening low mood, unusual agitation, or a marked change in appetite or sleep. Call 911 or go to an emergency department for chest pain, fainting, or a racing or irregular heartbeat.

Why clinical research matters for ADHD

Identification is the open question. The diagnosed rate among Canadian children and youth rose from 6.7% in 2019 to 8.4% in 2023, and the survey does not explain the rise. At the same time the Centre for ADHD Awareness, Canada says ADHD remains under-recognised, under-diagnosed and misdiagnosed here, and there is no national Canadian estimate of how many adults have it. The authors of the Global Burden of Disease 2021 analysis reached a similar conclusion internationally, judging their own estimate for people under 20 too low, partly because the severity weights come from a study run more than 20 years ago and do not capture emotional dysregulation, and partly because co-occurring conditions were left out. Canada’s national practice guidelines were last updated in January 2020. Studies are currently looking at better ways to diagnose ADHD in adults and in groups where it is often missed, behavioural, digital and coaching programmes, medicines in both the non-stimulant and stimulant groups, the overlap between ADHD and sleep problems, anxiety, mood and substance use, and how assessment and follow-up services can be organised so people can actually reach them.

Clinical studies are how any of that gets tested. Taking part is voluntary, you give informed consent before anything begins, and you can stop at any time without affecting the care you get from your own doctor. Joining a study does not mean giving up your current treatment, and no one can tell in advance whether a study will help you personally.

Learn more from Canadian sources

• Canadian ADHD Resource Alliance: practice guidelines and clinician directory
• Centre for ADHD Awareness, Canada: information and advocacy
• Centre for Addiction and Mental Health: ADHD
• Public Health Agency of Canada: chronic conditions in childhood, including ADHD