Neurodevelopment

Neurodevelopment is the process by which the nervous system forms and matures, from the first neural tissue in early pregnancy through the reorganization of the brain in adolescence.

It proceeds in overlapping stages: neurons are generated and migrate to their positions before birth, connections form rapidly in infancy, unused connections are pruned through childhood, and myelination that speeds signaling continues into the mid-twenties, with the prefrontal cortex finishing last. Each stage is guided by genes and shaped by nutrition, sleep, stress, relationships and exposures to substances in the womb and in early life.

Neurodevelopmental disorders, including autism spectrum disorder, ADHD, intellectual disability and some epilepsies, arise when these processes are altered, and they are assessed through developmental screening, standardized testing and clinical observation. The endocannabinoid system is active during brain development and helps guide neuron migration and connection formation, which is one reason health authorities advise against cannabis use during pregnancy, breastfeeding and adolescence. Cannabinoid research in neurodevelopmental conditions is early, and the one approved cannabidiol drug is for specific seizure disorders rather than for development itself.