When did ADHD become a diagnosis?

In 1968 the first official diagnosis was called hyperkinetic reaction of childhood

The first edition of the Diagnostic and Statistical Manual of Mental Disorders, published in 1952, had no category for what we now call ADHD. The second edition, DSM-II in 1968, added hyperkinetic reaction of childhood or adolescence, described in a few lines as overactivity, restlessness, distractibility and short attention span that usually diminishes in adolescence. The emphasis was on movement, the condition was assumed to belong to childhood, and the word reaction reflected the psychoanalytic thinking of the time, in which symptoms were reactions to circumstances rather than conditions in their own right.

Even in 1968 the category was not invented from nothing. Clinicians had been describing restless, inattentive children for over a century, and in the 1950s and 1960s terms such as hyperkinetic impulse disorder and minimal brain dysfunction were in common use in North American paediatrics. DSM-II gave that clinical experience an official name and a code, which is what turns a description into a diagnosis: something that can be recorded, counted, researched and, eventually, treated under a shared standard.

The World Health Organization's classification followed a similar path. ICD-8 and ICD-9 used hyperkinetic syndrome of childhood, and for decades the international and American systems used different thresholds, with the ICD version stricter and less often diagnosed. That gap explains some of the differences in diagnosis rates between countries that persisted into the 2000s.

In 1980 DSM-III made inattention the core problem and created attention deficit disorder

The decisive change came with DSM-III in 1980. Drawing on research from the 1970s, particularly Canadian psychologist Virginia Douglas's work at McGill showing that difficulties with sustained attention and impulse control were more central than overactivity, the manual renamed the condition attention deficit disorder and allowed two forms: with hyperactivity and without. For the first time there were explicit symptom lists, a required number of symptoms, an age-of-onset rule and a duration rule, which made the diagnosis reproducible between clinicians.

DSM-III-R, the 1987 revision, collapsed the two forms into a single category and gave it the name still used today, attention-deficit hyperactivity disorder. The manual also acknowledged for the first time that symptoms could persist into adulthood, though the criteria and examples were still written about children. The abbreviation ADD lingered in everyday speech for years, and still surfaces, but it has not been an official diagnosis since 1987.

Between 1994 and 2013 the manual added subtypes and then wrote adults into the criteria

DSM-IV in 1994 separated the symptoms into two lists of nine, inattention and hyperactivity-impulsivity, and defined three subtypes: predominantly inattentive, predominantly hyperactive-impulsive and combined. The inattentive subtype, in particular, brought many quieter children, and later many adults, especially women, into view who had never fit the picture of a hyperactive boy. Onset of symptoms was still required before age seven.

DSM-5 in 2013 is the edition that matters most for adults. It moved the age-of-onset requirement from seven to twelve, because adults could rarely date symptoms that precisely, reduced the symptom threshold from six to five for people aged 17 and older, added adult examples to each symptom, replaced subtypes with presentations that can change over a lifetime, and removed the rule that ADHD could not be diagnosed alongside autism. The text revision in 2022, explained in what does DSM-5-TR mean?, kept those criteria.

In Canada the diagnosis is made with the DSM and coded with the ICD, under CADDRA guidelines

Canadian clinicians diagnose ADHD using DSM-5-TR criteria, while hospitals and provincial health systems record diagnoses using the Canadian version of ICD-10. ICD-11, which came into effect internationally in 2022, replaced hyperkinetic disorder with attention deficit hyperactivity disorder and brought the two systems much closer together. The Canadian ADHD Resource Alliance, CADDRA, published the first national practice guidelines in the mid-2000s and the current 4.1 edition remains the reference that family doctors, nurse practitioners, psychiatrists and psychologists across the country work from.

• Diagnosis: DSM-5-TR criteria, applied through a clinical interview, rating scales and history.
• Coding and statistics: ICD-10-CA in hospitals and provincial databases, moving toward ICD-11.
• Practice standard: CADDRA's Canadian ADHD Practice Guidelines, which cover assessment and treatment across the lifespan.

The late arrival of adult criteria is why so many adults are being assessed for the first time now

Anyone who went through school before 1994 was assessed, if at all, against criteria built around hyperactive boys. Anyone assessed before 2013 faced a higher symptom threshold and an onset rule that was hard to meet from adult memory. Quiet, inattentive children, girls, and adults who coped by working harder were routinely missed, which is why a first diagnosis in your thirties, forties or fifties is now common rather than unusual, and why being told no as a child does not settle the question, as explained in can I be reassessed for ADHD as an adult if I was told no as a child?

The history also explains the mix of terms you may hear from older relatives or in old school files. Hyperactive, ADD and minimal brain dysfunction were all official or semi-official labels at different points, and a childhood note using one of them is relevant evidence in an adult assessment today, because it documents early symptoms even though the label has changed.