ADHD is often seen as a disorder for children — but it can also occur in adults. Adult attention-deficit hyperactivity disorder, explains the Mayo Clinic, has a wide variety of emotional and cognitive symptoms, including "impulsiveness, disorganization and problems prioritizing, poor time management skills, problems focusing on a task," mood swings and frequent frustration. If you experience all of these and also find it very difficult to follow through and complete tasks, it's possible you might have adult ADHD.

There's an interesting aspect to ADHD in adults: hyperfocus. "According to Pepperdine University, some people with ADHD may become hyperfocused. This makes them so intently focused on a task that they may not even notice the world around them," notes Healthline. "The benefit to this is when given an assignment, a person with ADHD may work at it until its completion without breaking concentration." Jenara Nerenberg observed for The Cut in 2016 that this can look like "flow", or being in the groove with a particular task, but it's actually a feature of the neurocognitive elements of ADHD.

A new study from King's College London has suggested that Leonardo Da Vinci's famous productivity and tendency to leave projects unfinished may be explained by adult ADHD. "The story of Da Vinci is one of a paradox—a great mind that has compassed the wonders of anatomy, natural philosophy and art, but also failed to complete so many projects," the scientists noted. They argue that evidence from Leonardo's life, including "difficulties with procrastination and time management" and his easily frustrated temperament, suggest he might have had ADHD. It's impossible to prove, of course, but it's a fascinating hypothesis.

The majority of ADHD diagnoses in children tend to be in boys, but research now confirms that girls get ADHD too, and simply present their symptoms in a different way. "It is thought that girls may be underrepresented in referrals to ADHD services and ADHD can go unrecognised [sic] in girls. There are several possible reasons for why this might be," notes Great Ormond Street Children's Hospital. "One theory is that girls tend to present with more inattentive symptoms than hyperactivity (although not always the case) and therefore are not noticed or seen as a problem." Girls' symptoms tend to be more 'inward' and relate to emotional distress and anger, which means they can be more easily missed.

ADHD actually is comprised of three types. The predominantly inattentive type means that people can be very easily distracted, don't appear to follow instructions, can't pay attention and are seriously forgetful, while the predominantly hyperactive-impulsive type fidgets, is restless, can't do anything quietly. talks a lot, is incredibly impatient, and acts "as if driven by a motor", according to Children and Adults with Attention-Deficit/Hyperactivity Disorder. The third type is a combination of these two.

There's not one cause for ADHD, but a study published in 2019 found that prenatal diet — what pregnant people ate during gestation — seemed to affect ADHD symptoms in kids once they'd been born. In particular, the study found that having higher levels of omega 6 than omega 3 in the umbilical cord was associated with a bigger risk of ADHD symptoms when the child was older. Omega 6 is a fatty acid found in seeds, oils and some nuts.

People with ADHD, according to a 2018 study, may have a higher likelihood of developing Parkinson's and other neurological conditions in old age than people who don't have the condition. The study didn't identify why, so it remains to be seen what might happen in the brain to create this link.

A strong component of ADHD is genetic, and a 2018 study identified several genes that appear to greatly contribute to its likelihood. They found 12 different genetic loci that seem to have a direct impact on ADHD diagnosis, which is a big step forward for understanding how the disease works and how it's inherited.

A study from Harvard in 2018 found that the earlier someone starts school, the more likely they are to be diagnosed with ADHD — possibly because young children who are bright enough to go to school early might be more vulnerable to ADHD anyway. The context of kids in classes with older children might also contribute to the development of symptoms, but there's a lot of research still needed.

A study in 2018 found that adults with ADHD feel empowered and flourish doing creative tasks, which may give them a unique advantage in the workplace. ADHD, according to this research, creates "outside-the-box thinking" that can provide fresh perspectives on problems.

A review of the science in Frontiers In Human Neuroscience in 2019 found that research actually doesn't agree on how ADHD shows up in brain structures.

"Although reduced frontal lobe volume has been frequently reported, there are discrepancies," the scientists behind the review said. They also noted that while a lot of science seems to support the idea that the prefrontal circuits of the brain might impair executive functioning (higher-level thinking like decision-making) in people with ADHD, further studies have shown that only applies to about 60% of ADHD adults. ADHD shows up in very different ways in the brain depending on many different factors, and a lot of those remain obscure.

Teens and young adults with ADHD appear to have a higher risk of contracting STIs, according to a 2018 study — but if they happen to be taking ADHD medication, that risk lowers significantly. It's possible that higher STI levels among people with untreated ADHD may be related to impulsivity, but it's not clear.

ADHD in women doesn't just have unique features and symptoms; it also has specific co-morbidities, or illnesses that tend to occur at the same time. A study in 2016 found that women with ADHD have a higher likelihood of also having an anxiety disorder, and also are more likely to have contemplated suicide. Additionaly, 39% report having substance use issues at some point in their lives, and insomnia and depression were also common.

Interestingly, a study of ADHD medication in 2016 found that people with ADHD who'd been on a course of treatment became better drivers. "Methylphenidate in particular shows beneficial effects on driving behaviours [sic] of ADHD drivers, including better driving performances in simulators, less speed variability, less incidence of speeding and less inappropriate use of brakes in simulated driving, fewer inattentive errors, less speed variability and smaller collision rate in real traffic," the researchers wrote. ADHD in general appears to be tied to a higher risk of crashes in adults; a study in 2019 found that teens with ADHD have a 62% higher chance of a crash in their first month of driving.

A 2019 study in Nature found that when it comes to adult ADHD, one symptom seems to be common in women and men: excessive mind wandering. If you find your mind drifting regularly, daydream chronically and can't seem to focus, even if you're trying very hard, ADHD may be behind it.

The genetics of ADHD are still being understood. A 2019 study of 2 million Swedish people looked at the genetic relationship between ADHD and borderline personality disorder (BPD), which involves extreme emotional reactions and mood swings. They found that people with ADHD had a higher likelihood of having BPD, and having a sibling with ADHD also raised the risk; the risk was highest with twins, but influenced siblings, half-siblings and even cousins. It was the same across both men and women.

ADHD that isn't managed can have an impact on relationships, according to the American Psychological Association. According to research, "patients with ADHD had a higher mean number of marriages, and that they and their spouses reported lower levels of marital satisfaction, than did people without ADHD." This doesn't at all mean that having ADHD is "bad" for relationships, but it does mean that people with ADHD and their partners should be mindful of the ways they communicate, just as with any relationship.

ADHD isn't just treated with medication. Many patients are actually given a combination of medications and therapies, including cognitive behavioral therapy. CBT appears to help people with ADHD manage their emotional responses to challenges and lessen the impact of serious symptoms like inattention and impulsivity. As with any treatment for mental illness, CBT isn't a cure, but it can be helpful to teach patients valuable coping skills.

A study from the University of California, Irvine, found that there's an unusual possible treatment for ADHD symptoms in children: therapy dogs. Two groups of children being treated for ADHD symptoms were compared, and the children who were given therapy dogs throughout their treatment did significantly better on tests of their attentiveness and social skills, though they showed the same results on impulsivity.

You may have heard that ADHD is becoming more common, but that doesn't mean it's an "epidemic" or "crisis." Rather, people are simply more aware of ADHD, and parents may know to seek out help for their children at younger ages, not to mention that adults can look out for the symptoms themselves.

We're gradually becoming more knowledgeable about ADHD, thanks to new science and perspectives. If you believe you may have the symptoms of ADHD, it's a good idea to visit a therapist who might be able to suggest what to do next.

If you or someone you know is seeking help for mental health concerns, visit the National Alliance on Mental Health (NAMI) website, or call 1-800-950-NAMI(6264). For confidential treatment referrals, visit the Substance Abuse and Mental Health Services Administration (SAMHSA) website, or call the National Helpline at 1-800-662-HELP(4357). In an emergency, contact the National Suicide Prevention Lifeline at 1-800-273-TALK(8255) or call 911.