As of 2017 there is clear evidence that long term use of cannabis increases the risk of psychosis, regardless of confounding factors, and particularly for people who have genetic risk factors.[18]
Cannabis use may precipitate new-onset panic attacks and depersonalization/derealization symptoms simultaneously.[20]
Chronic psychosis
According to one 2013 review, long term cannabis use "increases the risk of psychosis in people with certain genetic or environmental vulnerabilities", but does not cause psychosis. Important predisposing factors include genetic liability, childhood trauma and urban upbringing.[13] Another 2013 review concluded that cannabis use may cause permanent psychological disorders in some users such as cognitive impairment, anxiety, paranoia, and increased risks of psychosis. Key predisposing variables include age of first exposure, frequency of use, the potency of the cannabis used, and individual susceptibility.[21] A 2013 review stated that there exists "a strong association between schizophrenia and cannabis use...". The authors found that cannabis use alone does not predict the transition to subsequent psychiatric illness. Many factors are involved, including genetics, environment, time period of initiation and duration of cannabis use, underlying psychiatric pathology that preceded drug use, and combined use of other psychoactive drugs.[22]
A 2016 meta-analysis found that cannabis use increases the risk of psychosis, and that a dose-response relationship exists between the level of cannabis use and risk of psychosis. The analysis was not able to establish a causal link.[25] Another 2016 meta-analysis found that cannabis use only predicted transition to psychosis among those who met the criteria for abuse of or dependence on the drug.[26]
A 2016 review found that the epidemiologic evidence regarding cannabis use and psychosis was strong enough "to warrant a public health message that cannabis use can increase the risk of psychotic disorders," but also cautioned that additional studies are needed to determine the size of the effect.[27] A 2016 review said that the existing evidence did not show that cannabis caused psychosis, but rather that early or heavy cannabis use were among many factors more likely to be found in those at risk of developing psychosis.[28]
Ouch. Here is a gem:
Mania symptoms
Among those who have been previously diagnosed with bipolar disorder, cannabis may worsen the occurrence of manic symptoms.[35]
https://en.wikipedia.org/wiki/Long-term ... tal_health
"Don't eat bread because it might make me fat, but toke the fuck up and don't worry about the research that indicates this is not the best plan.."