Those at risk of mental illness are likely to hurry the onset of schizophrenia by 2.7 years simply by smoking pot, reports Miller-McCune. “The earlier the disease starts, the greater the social disruption it causes," says Michael Compton, one of the report's authors. "You’re less likely to finish high school, go off to college, get your first car and get married.” The scientists looked at 83 research papers, comparing 8,200 patients who used drugs and alcohol with 14,350 who did not.
“The risk is hidden,” Compton says. “We usually don’t know who is at risk until they have developed the disorder.” Schizophrenia, a mental disorder characterized by hallucinations and delusions, usually begins between the ages of 18 and 28 and is thought to be genetic about 85% of the time. But, “We know that adolescence is a critical time of brain development, so marijuana use during that time may have an effect on certain pathways in the brain that are involved with schizophrenia,” says Compton.