This integrative review brings together evidence showing that psychedelic use in emerging adulthood may support lasting improvements in mood, emotional regulation, cognitive flexibility, and openness, especially when use happens in supportive or intentional contexts. Studies highlighted in the chapter suggest that this developmental window—late teens through twenties—may be uniquely sensitive to experiences that promote meaning-making and identity formation, though findings are still early and largely correlational. Overall, the review argues that psychedelics may play a potentially constructive role in adult psychological development, while noting the need for more controlled research to understand who benefits, under what conditions, and with what safeguards.