Study: Serotonin Dysregulation Is the Common Denominator in Most ADHD Comorbidities

Study: Serotonin Dysregulation Is the Common Denominator in Most ADHD Comorbidities

August 13, 2025 Serotonin dysfunction occurs in nearly three-quarters of psychiatric and somatic comorbidities linked to ADHD, according to a new systematic review published in Neuroscience & Biobehavioral Reviews.1 The study identified 182 comorbidities in ADHD populations and found strong evidence linking 135 (74.2%) of them, including 91 psychiatric and 44 somatic conditions, to imbalances in the brain’s serotonergic system. “This association…