BackgroundADHD is the most prevalent neurodevelopmental disorder in children and has been associated with a lag in neuronal maturation. Sphingolipids are essential for myelination, neuronal function and development. We hypothesized that serum sphingolipid profiles are different in ADHD.ObjectiveTo characterize the serum sphingolipid profile in ADHD patients and two independent control groups: non‐affected relatives and non‐affected subjects without family history of ADHD.MethodSphingolipid profiles were determined by mass spectrometry in 77 participants (28 ADHD, 28 related controls and 21 unrelated controls). Diagnosis was based on the criteria of Diagnostic and Statistical Manual of Mental Disorders (DSM IV‐TR). Groups were compared by parametrical statistics.ResultsAll major sphingomyelins (C16:0, C18:0, C18:1 and C24:1), ceramide C24:0 and deoxyceramide C24:1 were significantly decreased in ADHD at relative reductions between 20‐30%. In our sample, decreased serum sphingomyelin levels distinguished ADHD patients with 79% sensitivity, 78% specificity and an estimated negative predictive value of 97%.ConclusionSerum sphingomyelin and select ceramides are decreased in ADHD patients. Longitudinal studies are required to evaluate if these findings reflect an ADHD specific pathomechanisms. Low serum sphingomyelins levels are a potential biomarker for ADHD.Grant support: None