Acute disseminated encephalomyelitis (ADEM) can cause cognitive impairment in children. However, long-term consequences for school performance and psychiatric morbidity have never been characterized. Our aim was to investigate long-term school performance and psychiatric morbidity after pediatric ADEM (<18 years).We identified all children with ADEM 2008-2015 in Denmark using hospital diagnostic codes for acquired demyelinating syndromes. We reviewed all medical records to validate ADEM including blinded MRI review. Reference children were the entire pediatric (<18 years) population or randomly sampled sex and age-matched reference children. Outcomes were from nationwide population-based registers on special needs assistance, grade point average, highest completed education, in-hospital psychiatric hospital diagnoses, out-of-hospital psychiatric consultations or psychopharmacological drug prescriptions.52 children had ADEM (median onset age: 5.5 years; median age at follow-up end: 13.4 years). Secondary school grade point average was similar among children with ADEM and reference children; however, children with ADEM had increased psychiatric morbidity (hazard ratio = 2.4; 95% confidence interval = 1.2-5.1; p = 0.02), primarily due to increased drug prescriptions for sleep problems and depression.Children with prior ADEM have increased sleep problems and possibly also depression; however, school performance is seemingly unaffected. Clinicians should consider problems with sleep and mood at follow-up.