New Study Finds Half of Adult ADHD Trials Lack Clear Diagnostic Standards

A new research review published by Cambridge University Press evaluated 292 random control trials (RCTs) studying Attention Deficit Hyperactive Disorder (ADHD) in adults and found that half of the studies do not use a clear diagnostic criterion to ensure participants have the condition.

“Our finding that half of the RCTs exhibited little or no interest in securing the validity of the ADHD diagnosis and that it was unclear who made the diagnosis in 2/3 of the studies is certainly alarming,” the authors wrote. “The diagnostic assessment is the foundation, which all subsequent analyses are built upon. As long as it remains unclear precisely what disorder is being examined in scientific studies, the findings of these studies will have limited value.”

The authors explained that the ADHD diagnostic criteria for adults are challenging for several reasons. ADHD originally began as a disorder to describe children, which was called Hyperkinetic Reaction of Childhood (or Adolescence) in 1968. The condition is described as “overactivity, restlessness, distractibility, and short attention span, especially in young children; the behavior usually diminishes in adolescence.”

The authors note that parents and teachers were responsible for observing this behavior in children and reporting the behavior to health professionals. That was the foundation of a clinical diagnosis in the DSM-II. “In the subsequent versions of the DSM, the diagnostic criteria for ADHD have been diluted and become more inclusive,” the study authors wrote.

The diagnostic criteria was intended for use in children based on observations made by parents and teachers. Diagnosis for adults relies solely on self-reports made by the individual, including retrospective recall of childhood symptoms, which the authors say is “notoriously poor.” The DSM 5 diagnostic criteria were not tested on adults before publication.

A systematic review from 2023 referenced by the authors found that most clinical samples found that less than 20% of those testing positive for ADHD were actually false positives. This is based on self-reporting diagnostic criteria. The authors of the 2023 review said the highest rate was 61%, meaning 39% of those who test positive actually do not have ADHD.

Dr. Richard Saul authored the book “ADHD Does Not Exist: The Truth About Attention Deficit and Hyperactivity Disorder,” and also wrote an op-ed for Time Magazine in 2014. Dr. Saul explained that only five out of 18 behaviors, which most people can relate to, include poor organization skills, a tendency to lose things, or failing to pay attention to details.

Dr. Saul said he has identified over 20 conditions that lead to the same symptoms of ADHD and that each one of these conditions requires a different approach for treatment. Some of these conditions include sleep disorders, vision and hearing problems, substance abuse, iron deficiency, allergies, bipolar disorder, and obsessive compulsive disorder among others. Dr. Saul stressed that stimulants are not an appropriate medication for people who are suffering from these particular conditions, which could be misdiagnosed as ADHD.

According to the CDC, 6% of U.S. adults are diagnosed with ADHD based on self-reports, which equates to 15.5 million. About one-third of adults diagnosed with the condition have taken stimulants within the last year to treat the condition.

Margaret Sibleyis, a professor of psychiatry and behavior sciences, published an article this week for AEON stating that adult ADHD “is becoming more inclusive” and “that’s not the same as being overdiagnosed.” Sibleyis wrote that an ADHD diagnosis is the extreme end of a continuum in which the average adult experiences two to three symptoms and can cross the clinical threshold during particularly stressful periods.

Sibleyis describes a clinical edge case by the name of Rebecca, who at the age of 40 clicked on Facebook ads that suggested she may have ADHD. The ads read, “Working hard but not moving up? You might have undiagnosed ADHD,” and “Indecisive? Anxious? A two-minute quiz can tell you if you have ADHD.”

Sibleyis said Rebecca has had a “moderate amount of relationship and employment instability,” which “can be linked to a pattern of restlessness.” With only three symptoms of inattention and two of hyperactivity, the clinician could make the determination based on an interview with Rebecca’s boyfriend, who describes behaviors of forgetfulness, distractibility, and talkativeness.

The clinician would make the determination based on whether Rebecca’s symptoms are interfering with her ability to function. Different clinicians could easily come up with different determinations for Rebecca.

Diagnoses of children with ADHD and subsequent medication prescriptions are also questioned as rates continue to rise. In addition, the proliferation of technology like smartphones and tablets has significantly increased the amount of screen time. 40% of children consistently use a tablet by the age of two, and children under eight have increased gaming time by 65% over the last four years.

A 2024 study found 10.5% of children had a current ADHD diagnosis, and 53.6% of those with a diagnosis received medication, which equates to more than four million children in the United States. 77.9% had at least one co-occurring disorder, including depression and anxiety, which the authors said can be hard to distinguish from ADHD.

The FDA announced this week that extended-release stimulants, like ritalin, that are prescribed for ADHD will have a weight loss warning for children under 6. These products are only approved for children over the age of 6, but it can and is prescribed off-label for young children. The CDC website states that medication should only be given to children under 6 after behavioral therapy has been tried because stimulant medication is less effective and has more side effects for this age group.

The 2016 National Survey of Children’s Health (NSCH) found 62% of children aged 2-7 were taking medication, and 46.7% received some behavioral treatment within the last year. The 2022 survey found 18% of children aged 2-5 diagnosed with ADHD received medication, and 69% of children aged 6-11.