What people believe
The belief is persistent: ADHD is the result of poor discipline, permissive parenting, too much screen time, or a chaotic home environment. The child just needs firmer boundaries. The adult just needed better upbringing. This belief is not limited to casual opinion — it surfaces in school meetings, family conversations, and sometimes from health professionals who should know better.
What the evidence says
ADHD is one of the most heritable conditions in all of psychiatry. A meta-analysis of 37 twin studies found a mean heritability of 74% — meaning that approximately three-quarters of the variation in ADHD liability is attributable to genetic factors.1 This heritability is comparable to that of autism spectrum disorder, bipolar disorder, and schizophrenia. Twin studies using clinical diagnoses (rather than self-report) estimate heritability at 77–88%.2
The heritability is similar in males and females, similar for inattentive and hyperactive-impulsive presentations, and stable across the lifespan.1 A 2023 genome-wide association study identified 27 specific genetic loci associated with ADHD risk, with some likely causal.3 Family studies show that first-degree relatives of someone with ADHD are 5 to 10 times more likely to have the condition than the general population. If a parent has ADHD, there is approximately a 40% chance their child will too.4
Parenting does not cause ADHD. However, parenting quality can influence the severity of symptoms and the development of co-occurring problems. A chaotic home environment can worsen executive function challenges, and harsh or inconsistent parenting can contribute to oppositional behaviour — but these are secondary effects on a condition that has its origins in neurodevelopment and genetics, not in how a child was raised.5
What to do instead
If someone attributes your ADHD — or your child's — to parenting failures, the response is straightforward: ADHD has a heritability of 74%, supported by decades of twin, family, and adoption studies. It is a neurodevelopmental condition with identified genetic architecture, not a product of discipline style. Good parenting supports a child with ADHD. It does not prevent the condition from existing.