HINT1 and attention deficit-hyperactivity disorder: Recently, neuropsychiatric disorders have been reported in patients with recessive HINT1 variants, expanding the phenotypic spectrum of this condition; in particular, Morel et al. found an increased incidence of neurodevelopmental and psychiatric features such as intellectual deficiency (ID), attention deficit hyperactivity disorder (ADHD), generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), and mood disorders [3].