The association between cannabis and psychosis has long been a matter of debate, with cannabis widely perceived as a harmless recreational drug.
Heavy cannabis use at a n young age, in association with genetic liability to psychosis and exposure to environmental stressors like childhood trauma and urban upbringing increases the risk of psychotic outcome in later life.
Cannabis acts as a component cause of psychosis, that is, it increases the risk of psychosis in people with certain genetic or environmental vulnerabilities, though by itself, it is neither a sufficient nor a necessary cause of psychosis.”