Just before Katie Marsh dropped out of college, she began to worry that she might have attention deficit/hyperactivity disorder.

“Boredom was like a burning sensation inside of me,” said Marsh, who is now 30 and lives in Portland, Oregon. “I barely went to class. And when I did, I felt like I had a lot of pent-up energy. I had to move around all the time.”

So she asked for an ADHD evaluation — but the results were inconclusive. She never did return to school. And only after seeking help again four years later was she diagnosed by an ADHD specialist.

“It was pretty frustrating,” she said.

ADHD is one of the most common psychiatric disorders in adults. Yet many health care providers have uneven training on how to evaluate it, and there are no U.S. clinical practice guidelines for diagnosing and treating patients beyond childhood.

Without clear rules, some providers, while well-intentioned, are “making it up as they go along,” said Dr. David Goodman, an assistant professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine.

This lack of clarity leaves providers and adult patients in a bind.

“We desperately need something to help guide the field,” said Dr. Wendi Waits, a psychiatrist with Talkiatry, an online mental health company. “When everyone’s practicing somewhat differently, it makes it hard to know how best to approach it.”

Can ADHD symptoms emerge in adulthood?

ADHD is a neurodevelopmental disorder that begins in childhood and is typically characterized by inattention, disorganization, hyperactivity and impulsivity. Patients are generally categorized into three types: hyperactive and impulsive, inattentive, or a combination of the two.

The latest data suggests that about 11% of children ages 5 to 17 in the United States have been diagnosed with ADHD, and about 4% of adults are estimated to have the disorder. But as recently as two decades ago, most providers “didn’t really believe in adult ADHD,” Goodman said.

For the most part, that’s no longer the case. And during the pandemic, stimulant prescriptions, primarily used to treat ADHD, “sharply increased,” according to a study published in JAMA Psychiatry in January.

When diagnosing the condition, providers rely on the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, the American Psychiatric Association’s official manual of mental disorders, which contains a somewhat arbitrary requirement: In order to meet the diagnostic criteria for ADHD, significant symptoms, such as continual forgetfulness and talking out of turn, should be present in at least two settings before age 12.

But sometimes, older patients either do not recall childhood symptoms or say those symptoms were mild.

Judy Sandler, 62, of Lincolnville, Maine, was not diagnosed with ADHD until her mid-50s, after retiring from her job as a teacher: It was the first time in her life she felt like she couldn’t get anything done. She wanted to write, but when she would sit down, she immediately had the urge to get up and do something else: “I’ll just do the laundry,” she would think. “And then go walk the dog.”

During her working years, she benefited from a “hyper-structured” schedule — up until retirement. “All of a sudden, I felt like the rug had been pulled out,” she said.

Patients like Sandler fall into a gray area. She did not recall having significant symptoms in school or at home; rather, she indicated that her symptoms became most problematic later in life. Her husband of 33 years, however, had noticed symptoms for years: She was forgetful, and found it challenging to slow down.

“There’s a lot more subtlety in making this diagnosis — especially in high-functioning, bright people — than just a symptom checklist,” Goodman said.

Is the DSM missing symptoms?

The DSM lists nine symptoms of inattention and nine symptoms of impulsivity-hyperactivity that are used to evaluate whether an adult or a child has ADHD.

The DSM does not formally include symptoms related to emotional dysregulation, which is when someone has difficulty managing their mood. It also does not mention deficits of executive functioning, or problems with planning, organization and self-regulation. But studies have found that these are some of the most common symptoms that adults with ADHD experience, said Russell Ramsay, a psychologist who treats adult ADHD.

Goodman is working with Ramsay and other ADHD specialists to develop the first U.S. guidelines for diagnosing and treating adults with ADHD, in collaboration with the American Professional Society of ADHD and Related Disorders.

There is an urgency to do so, in part because of new research from the past decade. In addition, while adult ADHD is often undiagnosed and untreated, some people might be getting diagnosed who don’t actually have the disorder — and given medication they don’t truly need, Goodman said.

ADHD or something else?

For adults, a proper diagnosis typically requires an interview with the patient; a medical and developmental history; symptom questionnaires; and, if possible, conversations with other people in the patient’s life, like a spouse.

“There are no shortcuts,” said Dr. Lenard Adler, a professor of psychiatry at the NYU Grossman School of Medicine, while speaking to providers at the American Psychiatric Association conference in May. “This isn’t easy.”

While everybody has some trouble paying attention or is restless from time to time, he added, it’s really how pervasive and significant the symptoms are and how consistent and impairing they’ve been throughout the patient’s life that helps doctors decide if an ADHD diagnosis is appropriate.

But several factors make it tricky. People who consider themselves heavy users of digital technology are more likely to report ADHD symptoms, research suggests.

There’s a “chicken or the egg” dilemma, Waits said. Are people with ADHD drawn to using digital technology more than the average person? Or did their ADHD develop because of their technology use?

People with ADHD are also likely to have a coexisting condition, like substance use disorder, depression or anxiety, which can make it hard for both doctors and patients to understand if their symptoms are a result of ADHD, particularly if symptoms overlap.