Long-term health research on regular marijuana use, particularly regarding developing brains and mental health, is still evolving, and policy is moving faster than the science. Some researchers have flagged potential links between heavy regular use and mental health effects, particularly in adolescents, an area critics argue warrants more caution before further expansion. Critics argue this evolving research base counsels patience rather than rapid nationwide change. This scientific uncertainty, in their view, is a reasonable basis for continued caution.