This was a double‐blind, parallel‐group, randomized, placebo‐controlled clinical trial (the NF1‐EXCEL trial: Examining the Cognitive and Electrophysiological benefit of Lamotrigine in Neurofibromatosis type 1; Clinicaltrials.gov identifier NCT02256124), with the aim of enrolling 60 adolescents with NF1 aged 12 to 17  years 6 months. Here, NF1 is linked to neurofibromatosis type 1.