ADHD is a neurodevelopmental disorder. “That means it begins from childhood, even if it’s not diagnosed until you’re an adult, or even if you don’t become aware of symptoms until later on in life,” says Margaret Paul, a clinical psychology PhD candidate at Saint Louis University and the lead author of a January 2025 study on ADHD diagnoses in Psychiatric Research & Clinical Practice.
The exact cause of ADHD is unknown, but so far, research suggests it’s largely genetic. Parents with ADHD have higher chances of having children with ADHD, and if one child has ADHD, a sibling is more likely to have it, too.
Some environmental factors increase the risk of developing the condition. These include:
X Being born prematurely or at a low birth weight
X Exposure to alcohol and tobacco in utero
X High lead levels
X Certain brain injuries
However, the following environmental conditions are not linked to ADHD:
X Poor parenting
X Sugar intake
X Socioeconomic status
While it is hoped that future research will help illuminate the precise cause of ADHD, in the meantime, the effects are clear: People with ADHD experience differences in the frontal lobes of their brains, resulting in difficulty to with what’s called executive functioning. Executive function includes a number of brain processes involved in memory, attention, and organization. Because these three attributes are central to so many facets of life, ADHD symptoms can be far-reaching and quite detrimental.
According to Paul, “ADHD symptoms are persistent, and they affect multiple areas of life and significantly interfere with daily functioning.”
ADHD is so disruptive to daily life because it’s a “syndrome of self-regulation difficulties,” explains private practice psychologist J. Russel Ramsay, former clinical professor at the University of Pennsylvania School of Medicine and cofounder of the University’s Adult ADHD Treatment and Research Program. “One way to think about it is: How efficiently do you do what you set out to do,” he says.
There are three types of ADHD, based on the predominant symptoms someone experiences. They are called mostly inattentive ADHD, mostly hyperactive-impulsive ADHD, and combined ADHD.
The type of ADHD is determined by evaluating a person’s symptoms across two major categories.
Inattention: Trouble staying on task, paying attention, or keeping things organized.
Hyperactivity and Impulsivity: Restlessness, excessive talkativeness, inability to sit still, impatience with waiting, and interrupting.
While anyone can experience these feelings and behaviors at some point, in people with ADHD, they are significant enough to cause “functional consequences,” according to Lenard A Adler, MD, director of the Adult ADHD Program at NYU Langone Health. This means it affects the individual’s life in some tangible and negative way.
In the 1980s, ADHD was known as attention-deficit disorder. For several years, there were two subtypes: attention-deficit disorder with or without hyperactivity. By the late 1980s, the psychology community had settled on attention-deficit/hyper-activity disorder.
We may now be experiencing a bit of a course correction in diagnoses. Paul’s January 2025 report found a 15% increase in the incidence of ADHD among adults from 2020 to 2023. But this jump “doesn’t necessarily mean that more people actually have ADHD,” she says. “Instead, it may point to increased awareness, access to care, and reduced stigma surrounding mental health. More adults may be recognizing long-standing symptoms and seeking help. As we reach more people and apply better diagnosis tools, it’s kind of like shining a flashlight in a dark room: What was always there is now visible.”
ADHD incidence stayed stable for kids and teens for the same period in her study.
It hasn’t been easy for girls and women to get accurately diagnosed with ADHD. It is more common in boys and men than in girls and women, but it’s been difficult to determine if that’s because the condition truly affects more males than females, or if societal and gender expectations affect how behaviour is assessed. For example, in some studies, boys and girls exhibited the same types of behaviour, but it was more often identified as hyperactivity and impulsivity in boys than in girls, according to Ramsay. Other research suggests girls are socialized to behave more obediently and, therefore, may be masking ADHD symptoms.
Challenges of living with ADHD:
At school, Adler says, children and teens might leave test questions blank because they’ve skipped around the exam. At work, adults may have trouble planning ahead to complete long-term projects. They may interrupt colleagues or managers during meetings. Parents with ADHD may have trouble playing with their kids after work because that’s “unstructured time.” Executives may appear to function well with a lot of support, but “when their executive assistant goes on vacation and that support is removed, hey have much greater difficulty,” he says.
Adults with ADHD may not pay attention when driving. ADHD is also associated with higher rates of anxiety, depression, and substance use disorder; speeding tickets; car crashes; and riskier sexual behaviour. Many people with ADHD also face misunderstandings and stigmas from friends, family, and colleagues.
Anxiety, depression, and other mental health issues don’t just occur alongside ADHD. Sometimes, they are confused with ADHD. Healthcare providers who diagnose ADHD are trained to look closely at the potential underlying causes of such symptoms because it’s so common to have another condition alongside ADHD, Adler says.
There is also some similarity with autism spectrum disorder, another condition typically present since childhood that’s garnering additional attention lately. More than half of people with autism have signs of ADHD, and up to one quarter of kids with ADHD have some autism symptoms.
Treatment: ADHD is typically treated with a combination of psychotherapy, education. and medication. In kids younger than 6 with ADHD, health care providers may start by training parents how to help modify and manage their child’s behaviour. Behavioural and cognitive therapy alongside prescription stimulant medications is often helpful for adults. Some people also benefit from executive coaching.
This is an abridged version of an article written by Sarah Klein in Time Magazine
