Children with attention deficit hyperactivity disorder (ADHD) receive a diagnosis based on their behavior: age-inappropriate fidgeting, inattentiveness, hyperactivity, and trouble sitting still and concentrating. However, according to new research presented today at the Pediatric Academic Societies annual meeting in Vancouver, Canada, these behaviors may also be linked to childhood trauma.

A research team analyzed data about 65,680 children ages 6 to 17. (The data was taken from the 2011-2o12 National Survey of Children’s Health.) The children’s parents answered questions about whether their kids had been diagnosed with ADHD, how severe their symptoms were, and whether they were taking any ADHD medications. The parents also reported on whether the children had had any of nine adverse childhood experiences (ACEs): poverty, divorce, the death of a parent or guardian, domestic violence, neighborhood violence, substance abuse, incarceration, familial mental illness, or discrimination.

“Diagnoses of ADHD have increased over the last decade, and there has been a concomitant rise in stimulant medication use,” said Nicole Brown, an assistant professor of pediatrics at the Children’s Hospital at Montefiore and lead author of the study, in an interview with Healthline. “Many of my patients also experience trauma during childhood, which often exacerbates ADHD symptoms and poses diagnostic challenges with respect to teasing out whether their symptoms directly result from the trauma they experience.”

About 12 percent of the children who participated in the survey had been diagnosed with ADHD. Parents reported that these children had also experienced higher rates of all of types of ACEs than children without ADHD.

The children with ADHD were also more likely to have experienced a greater number of adverse events. Seventeen percent of children with ADHD had experienced four or more ACEs, as opposed to 6 percent of children without ADHD. The children who had dealt with four or more ACEs were almost three times are likely to be using an ADHD medication as children with three or fewer ACEs, and their parents rated their ADHD as being more severe.

ADHD and Trauma: The Chicken and the Egg

How is ADHD connected to stress and trauma? There could be a number of explanations.

First, it’s possible that doctors are simply mistaking the signs of trauma in children for ADHD. “What we find is that there is often an overlap in the symptoms of children who have ADHD and children who have experienced trauma, particularly small children,” said Alicia Lieberman, professor and vice chair for academic affairs at the University of California, San Francisco, Department of Psychiatry and the director of the Child Trauma Research Program at San Francisco General Hospital, in an interview with Healthline. “The inability to concentrate, the fidgetiness, the inability to pay attention, the distractibility, the restlessness, and the irritability are often behaviors that trigger a diagnosis of ADHD. And often, the people making the diagnosis do not ask what happened to the child, what kind of experiences the child has had.”

Brown agrees that this may explain her findings. “Studies have also shown that symptoms of post-traumatic stress disorder (PTSD) or acute stress disorder resulting from adverse life events closely resemble ADHD symptoms, so there is a high likelihood for clinicians to diagnose ADHD and overlook a possible trauma history,” she said.

Another explanation is that children with ADHD may be more likely to get into trouble and to experience traumatic events as a result. “Children with ADHD can become more impulsive, can be more annoying to parents that might be depleted, so children with ADHD might be at greater risk for being maltreated or getting into accidents, which might in turn trigger PTSD,” explained Lieberman.

Finally, researchers know that stress in the early life environment might affect the development of the brain. “It’s also possible that being exposed to a traumatic event increases the likelihood of developing psychiatric disorders that have a range of manifestations, including anxiety, post-traumatic stress disorder, and ADHD,” Lieberman said.

Sullivan added, “Early life trauma and stress can interact with genetics to produce different disorders based on the age the trauma was experienced and the particular type of stress or trauma. Different-aged children, and children with different genetics, and children with different personalities, will respond differently to a given stress.”

Are We Medicalizing Stress?

Rising rates of ADHD diagnosis and medication use raise the question: are we turning normal levels of life stress into a medical condition? Lieberman points out that more than 60 percent of children report that they have been exposed to some kind of victimization in the previous year, and more than 10 percent have had five or more exposures. For many children, ACEs aren’t rare, they’re the norm.

And when kids are under stress, they’re more likely to act out. “When a child is presenting difficult behavior, the first thing to ask is ‘What happened to the child?’ rather than ‘What is wrong with the child?’” said Lieberman. “The recommendation that the authors of the study make about the importance of screening for trauma exposure in every child that is showing symptoms that can be associated with ADHD is extraordinarily important and timely.”

In these circumstances, medications probably aren’t the answer. “While stimulant medications may prove beneficial for some children, they may not be the most effective management strategy for all children,” said Brown. “Children with ADHD diagnoses who have experienced trauma may additionally benefit from specific behavioral interventions that are tailored to addressing their underlying trauma histories.”

However, Sullivan cautions against drawing too many conclusions about a child’s past from his or her diagnosis of ADHD. “Not all children with ADHD have had early life adversity,” she said. ADHD also isn’t necessarily a sign of other disorders to come. “Sometimes, when someone has ADHD, they maintain those ADHD symptoms throughout life, changing somewhat, but they still have the diagnosis of ADHD.”

It will be many years before the root causes of ADHD are fully understood. Until then, doctors must try to figure out which symptoms are caused by trauma, while also ensuring that children with ADHD get proper treatment for the disorder itself.