This was a self-reported survey of 1738 students with ADHD at Washington State University and was published in October 2021 in the Journal of Attention Disorders.
Students were self-medicating with cannabis, and took an online survey that measured ADHD symptoms, cannabis use, perceived effect of cannabis, medication side effects, and executive dysfunction.
"Participants with ADHD who have used cannabis reported that cannabis has acute beneficial effects on many symptoms of ADHD (e.g., hyperactivity, impulsivity). Further, they perceived cannabis to improve most of their medication side effects (e.g., irritability, anxiety)."
There were also moderate associations between frequent use and the mitigation of ADHD-related executive dysfunction.