Previous studies on tobacco smoking have suggested that nicotine might alter dopaminergic, cholinergic, and glutamatergic neurotransmitter signals. Studies of adolescent nicotine exposure show that tobacco smoking may potentially influence brain development — or even restructure the brain in terms of a decrease in gray matter in the prefrontal cortex — with adolescents who use inhalants having an increased risk of having psychotic disorders, strengthened negative emotions, and alterations in cognitive functioning. This is concerning, given the increasing usage of e-cigarettes among the adolescent population.