Almost one in four grown-ups who seek treatment for attention-deficit hyperactivity disorder (ADHD) might exaggerate or fake signs that they have the condition, according to a new report published in The Clinical Neuropsychologist and reported by

ADHD is a behavioral disorder with symptoms that include poor concentration, hyperactivity and impulsiveness.

For the study, researchers examined the medical records of 268 patients and checked answers they gave about their ADHD symptoms on interviews and questionnaires. Scientists found that 22 percent of patients who claimed they suffered from ADHD tried to make their symptoms appear worse.

In addition, in some cases, patients who exaggerated their symptoms actually had ADHD but wanted to ensure docs diagnosed them with the condition, said Paul Marshall, PhD, lead study author and clinical neuropsychologist at Hennepin County Medical Center in Minneapolis.

Other patients didn’t have the disorder, but instead were experiencing difficulties with their workloads and lives. “A lot of people think they have it because they are struggling, but it’s not because of the ADHD,” Marshall said. “Often times, it’s simply depression, anxiety or lack of sleep.”

Marshall suggested that ADHD patients also exaggerated their symptoms so they could get stimulant medications that boost concentration and focus. (Some college and graduate students use ADHD meds to enhance their academic performance and get a competitive edge.) And others just wanted the treatment for a cheap high, Marshall added.

ADHD drugs work by boosting the brain’s levels of dopamine and norepinephrine, chemicals associated with attention and behavior. When people who have ADHD take the drugs, these meds calm them down. But when people who don’t have the disorder take the drugs, the meds can become addictive—and that’s another serious illness.

In the United States, about 2 to 4 percent of the adult population has ADHD.

Click here to learn how too much TV can cause ADHD among young people.