THC at High Concentrations Disrupted Developing Human Neurons in the Lab, While Low Doses Had Minimal Effects

Human cord blood-derived iPSCs were differentiated into neural precursor cells and then into mature neurons. Cultures were exposed to anandamide or THC at 1 or 10 micromolar during dopaminergic differentiation. Neuronal function was assessed by electrophysiology (ion currents and synaptic activity). DNA methylation was analyzed in relevant gene promotor regions.

This study uses human-derived neurons rather than animal models to study THC's effects on brain development, making the findings more directly relevant to human biology. The concentration-dependent results suggest a threshold below which THC may have minimal developmental impact and above which significant disruption occurs.

Cannabis use during adolescence, when the brain is still developing, is a major public health concern. This study adds mechanistic detail: at high concentrations, THC disrupts the functional maturation of human neurons, particularly those becoming dopamine-producing cells. The dopaminergic system is central to reward, motivation, and executive function, making its disruption during development potentially significant for long-term cognitive outcomes.

In vitro study: neurons in a dish do not fully replicate the complexity of brain development in a living organism. The concentrations used may not directly correspond to THC levels in the developing human brain after cannabis use. iPSC-derived neurons may not perfectly recapitulate native neuronal development. Only two concentrations were tested.