In the spring, Riana Shaw Robinson learned that her 11-year-old son, Madison, had sprinted out of class to chase a squirrel through his school’s courtyard in Berkeley, Calif.

It’s not how her sixth grader would typically behave. But that day Madison hadn’t taken his Adderall — the medication that, in his words, helps his brain slow down, “from 100 miles per hour — like a car — to 70 miles per hour.”

Ms. Robinson said Adderall worked better for her son than the other medications they had used to treat his attention deficit hyperactivity disorder. With Adderall, he was calmer and better able to focus.

“He actually had a taste for what relief could look like,” Ms. Robinson said.

But for nearly a year now the medication — Madison takes the generic version — has been difficult to find. He has had to skip doses, sometimes for up to two weeks, because nearby pharmacies have been out of stock.

The family is rationing his pills this summer so that Madison, who recently turned 12, will have them during the school year.

“We try to manage with a couple of caffeine drinks during the day and soccer in the afternoons,” Ms. Robinson said, strategies that she said have helped her son regulate his emotions.

In July, the Food and Drug Administration posted more shortages in A.D.H.D medications, adding generic versions of Concerta and two types of Vyvanse capsules to the list. And in August, the F.D.A. and the Drug Enforcement Administration took the rare step of issuing a joint public letter acknowledging the shortage and asking manufacturers to increase production.

Parents and caregivers across the country are spending hours each month hunting down pharmacies with A.D.H.D. medication in stock and asking their doctors to either transfer or rewrite prescriptions, a process many equate to having a second job. Others pay hundreds of dollars out of pocket for name-brand drugs that are sometimes more readily available but, unlike generics, are not covered by their insurance. Some children end up taking similar but less effective medications or go without medication for months at a time because their families do not have the extra time or cash.

A.D.H.D., which is often characterized by inattention, disorganization, hyperactivity and impulsivity, is one of the most common childhood neurodevelopmental disorders. Because of the medication shortage, children across the country with the condition fell behind in their schoolwork over the spring, and their relationships often suffered as they struggled to regulate their emotions, according to interviews with multiple doctors and parents. Meanwhile, they all wonder: Why is this happening, and when will it end?

‘She couldn’t catch up’

One of the cruelest aspects of the A.D.H.D. medication shortage, some parents have said, has been the collateral damage to their children’s self-esteem.

Kari Debbink, who lives in Bowie, Md., said her daughter, who is about to enter her senior year of high school, would lose motivation to do her school work when her A.D.H.D. medication, Concerta, was not available in either the brand name or the generic version. Her grades, which had typically been B’s, plummeted — and so did her confidence.

“Once she got behind, she couldn’t catch up,” Ms. Debbink said. “By the end of the year, we were just trying to prevent her from failing classes.”

Drew Tolliver, 12, who lives in DeKalb, Ill., typically takes the generic version of Concerta, but since February, his family has had difficulty finding it.

When taking the medication regularly, Drew said, “I felt like I knew myself.”

“I felt like a better me,” he added, “like how ‘myself’ should be.”

His mother Amy Tolliver recently located the medicine — but she had to pick it up 40 minutes away from the gas company where she works 10-hour shifts, six days a week.

In the spring, Drew would refuse to go to class when he didn’t have his medication, said Michelle Tolliver, Amy’s wife and Dre