Attention-deficit/hyperactivity disorder (ADHD) in adults: evidence base, uncertainties and controversies

Attention-deficit/hyperactivity disorder (ADHD) was once thought to be solely a childhood condition. Now it is well established that it can persist into adulthood, with an estimated worldwide prevalence of around 2.5%. Additionally, up to 70% of individuals with childhood-onset ADHD continue to experience impairing symptoms as adults, even if they no longer meet the criteria for a formal diagnosis. The validity of adult ADHD initially faced strong criticism. Today, empirical research supports its descriptive validity (identifying characteristic signs and symptoms), predictive validity (concerning specific outcomes, courses, and responses to treatment), and concurrent validity (evidence related to its underlying causes and biological mechanisms). Despite this progress, unresolved questions and ongoing debates about adult ADHD persist. This paper summarizes current empirical evidence, alongside uncertainties and controversies, regarding the definition, epidemiology, diagnosis, etiology, neurobiology, and management of ADHD in adults. Crucially, we also include perspectives from individuals with lived experience of this condition, highlighting their views on unmet needs and priorities for improving care. Key uncertainties and controversies on adult ADHD include: a) the possibility of late-onset ADHD; b) the significance of emotional dysregulation as a core symptom; c) the definition and characterization of functional impairment; d) the persistence of psychiatric and somatic conditions after accounting for confounders; e) the relevance of executive dysfunction in the definition of the condition; f) the use of objective diagnostic measures; g) the long-term effects of treatments; and h) the role of non-pharmacological interventions. Further research on adult ADHD is urgently needed. Funding for studies on this condition lags behind that for childhood ADHD and other mental disorders in adulthood. Hopefully, efforts by clinicians, researchers and other stakeholders will ultimately help ensure that adults with ADHD are better understood, supported, and empowered to thrive.