Marijuana use, especially frequently (daily or nearly daily) and in high doses, can cause disorientation and sometimes unpleasant thoughts or feelings of anxiety and paranoia.1
People who use marijuana are more likely to develop temporary psychosis (not knowing what is real, hallucinations, and paranoia) and long-lasting mental disorders, including schizophrenia (a type of mental illness where people might see or hear things that are not really there).2 The association between marijuana and schizophrenia is stronger in people who start using marijuana at an earlier age and use marijuana more frequently.
Marijuana use has also been linked to depression; social anxiety; and thoughts of suicide, suicide attempts, and suicide.1
National Academies of Sciences, Engineering, and Medicine. The health effects of cannabis and cannabinoids: the current state of evidence and recommendations for research. Washington, DC: The National Academies Press; 2017.
Volkow ND, Swanson JM, Evins AE, et al. Effects of cannabis use on human behavior, including cognition, motivation, and psychosis: a review. JAMA Psychiatry. 2016;73(3):292-297.