For emergency room doctors, they are a dispiriting and familiar sight: Children who return again and again in the grip of mental health crises, brought in by caregivers who are frightened or overwhelmed.

Much has been written about the surge in pediatric mental health emergency visits in recent years, as rates of depression and suicidal behavior among teens surged. Patients often spend days or weeks in exam rooms waiting for a rare psychiatric bed to open up, sharply reducing hospital capacity.

But a large study published on Tuesday found a surprising trend among adolescents who repeatedly visited the hospital. The patients most likely to reappear in emergency rooms were not patients who harmed themselves, but rather those whose agitation and aggressive behavior proved too much for their caregivers to manage.

In many cases, repeat visitors had previously received sedatives or other drugs to restrain them when their behavior became disruptive.

“Families come in with their children who have severe behavioral problems, and the families really just are at their wit’s end, you know,” said Dr. Anna M. Cushing, a pediatric emergency room physician at Children’s Hospital Los Angeles and one of the authors of the study. “Their child’s behavior may be a danger to themselves, but also to the parents, to the other children in the home.”

The findings, published in the journal JAMA Pediatrics, analyzed more than 308,000 mental health visits at 38 hospitals between 2015 and 2020.

Compared with patients presenting with suicidal or self-harming behavior, those with psychotic disorders were 42 percent more likely to revisit the emergency department within six months, the study found; patients with impulse control disorders were 36 percent more likely; and patients with disorders like autism and A.D.H.D. were 22 percent more likely. Patients who required medications to subdue them were 22 percent more likely to revisit than patients who did not.

The results suggest that researchers should focus more attention on families whose children have cognitive and behavioral problems, and who may turn to emergency rooms for respite, Dr. Cushing said.

“I’m not sure we’ve been spending as much time talking about these agitated and behaviorally disregulated patients, at least on a national scale,” she said.

The frequency of revisits suggests that the care they receive in emergency rooms “is really not adequate,” she said.

Guidelines recommend that so-called chemical restraints — benzodiazepines or antipsychotics administered by injection or through an intravenous drip — be used as a last resort because they can be traumatizing or cause physical injury to the patient, medical staff or caregivers, said Dr. Ashley A. Foster, an assistant professor of emergency medicine at the University of California San Francisco.

The use of these drugs in pediatric emergency rooms has increased in recent years. Between 2009 and 2019, chemical restraint use increased by 370 percent, while mental health emergency room visits increased by 268 percent, according to a study that Dr. Foster and her colleagues published last year.

The drugs were used more often on Black patients, as well as on male patients between the ages of 18 and 21, the study found. Dr. Foster described those disparities as “concerning, and motivation for thinking about how to enhance equitable care.”

Dr. Christine M. Crawford, a child and adolescent psychiatrist at Boston Medical Center, said caregivers for children with behavioral disorders often turn to emergency rooms when “it gets to the point where someone could get hurt.”

“They enter sixth, seventh, eighth grades — that’s when we see those families that have been struggling for a long time,” said Dr. Crawford, who is also an assistant professor at Boston University School of Medicine.

Families in this situation, she said, “are quite isolated,” often hiding their struggles from friends and relatives. Emergency room treatment is comforting to caregivers but offers little long-term benefit, she said.

“It’s just putting a Band-Aid on the problem,” she said. “They go back home and they’re still waiting for that appointment to meet with a therapist.”

Dr. Andrea E. Spencer, a psychiatrist and researcher at Lurie Children’s Hospital of Chicago, said behavioral disorders might be dismissed as less pressing than suicidal thoughts or self-harm, when in fact “they are very high-risk behaviors and they are dangerous behaviors.”

“There is a tendency to sort of watch and wait and deprioritize those kids in terms of who are the most severe, and then they have the tendency to just get worse,” she said, adding that public hospitals might be reluctant to accept them as inpatients because they are disruptive.

“In many ways, these kids are actually harder to treat,” she said.

The JAMA study found that overall visits to pediatric emergency rooms for mental health crises increased 43 percent from 2015 to 2020, rising by 8 percent per year on average, with an increase in emergency visits for every category of mental illness. By comparison, emergency room visits for all medical causes rose by 1.5 percent annually.

Nearly one-third of visits were related to suicidal ideation or self-harm, and around one-quarter of patients presented with mood disorders, followed by anxiety disorders and impulse control disorders. Around 13 percent of patients made a repeat visit within six months.

“It causes a lot of moral distress for many of us, just because it doesn’t feel like the emergency department is always the right place or best place to take care of many of our patients,” Dr. Cushing said.

“But,” she added, “they really don’t have anywhere else to go.”