“The World Federation of ADHD International Consensus Statement: 208 Evidence-based conclusions about the disorder” is a scientific review of studies about attention-deficit hyperactivity disorder, published in the September 2021 issue of Neuroscience & Biobehavioral Reviews. (DOI link, full PDF, 30 pages, open access article licensed as CC-BY.) “Our aim is to provide current and accurate information about ADHD supported by a substantial and rigorous body of evidence.” Findings start: “The syndrome we now call ADHD has been described in the medical literature since 1775.”
The summary of findings includes:
- People with ADHD often show impaired performance on psychological tests of brain functioning, but these tests cannot be used to diagnose ADHD.
- Neuroimaging studies find small differences in the structure and functioning of the brain between people with and without ADHD. These differences cannot be used to diagnose ADHD.
- ADHD is rarely caused by a single genetic or environmental risk factor but most cases of ADHD are caused by the combined effects of many genetic and environmental risks each having a very small effect.
- The stimulant medications for ADHD are more effective than non-stimulant medications but are also more likely to be diverted, misused, and abused.
- Non-medication treatments for ADHD are less effective than medication treatments for ADHD symptoms, but are frequently useful to help problems that remain after medication has been optimized.
The Discussion section includes:
Epidemiologic studies have taught us that ADHD occurs around the world, but we know little about how culture affects the expression of ADHD symptoms or the response to treatment. Because most research about ADHD is based on Caucasian and East Asian samples, we must be cautious in generalizing our assertions to other groups. In addition, far more research pertains to males than females. We also need to learn more about ADHD in older adults. Future research into ADHD should examine more diverse samples from a wider range of cultural contexts.