Exploring the Relationship Between Apathy, Dopaminergic Signal, and Head Injury in Neurodevelopmental Disorders

Apathy is characterized by reduced motivation for goal-directed behaviour and may emerge following brain injury. Currently, little is known about apathy in children and adolescents with neurodevelopmental disorders (NDDs) exposed to repetitive head impacts. This exploratory study investigated associations between apathy, repetitive head-banging behaviour, and substantia nigra neuromelanin-sensitive MRI (NM-MRI) signal in youth with NDDs. Forty-seven participants (14 typically developing; 33 ADHD/ASD) completed Behaviour Assessment System for Children (BASC-3) measures, from which apathy-related items were harmonized across developmental forms and subjected to principal component analysis. A one-component solution explained 47.3% of variance and was used to derive apathy scores. Although head-banging severity and NM-MRI signal were not independently associated with apathy, a significant interaction emerged, whereby greater head-banging severity strengthened the relationship between apathy and substantia nigra NM-MRI signal. These preliminary findings suggest repetitive self-injurious head impacts may influence dopaminergic systems linked to motivational dysfunction in youth with NDDs.