A connection between psychosis and cannabis use was believed to exist for a long time. However, it can be difficult to understand how cannabis use and psychosis are linked together due to some challenges such as disease complexity and limitation in scientific to study such a connection. It was suggested that psychosis can be caused by cannabis, but at the same time, it was also suggested that cannabis use can be caused by psychosis. Also, the link between cannabis use and psychosis could be bidirectional (Degenhardt et al., 2018).
It was shown that Schizophrenia patients who often used cannabis before the disease onset were more inclined to develop schizophrenia compared to people that did not use cannabis or used it less frequently (Aas et al., 2018).
Some markers and/or cognitive deficits related to schizophrenia could be counteracted with the help of cannabis (usually with high THC) (Rentzsch et al., 2017; Roser et al., 2018).
It was shown that there is a connection between impaired frontostriatal connectivity and schizophrenia. Improved connectivity of these areas was observed by oral administration of CBD (600 mg) (Grimm et al., 2018).
Some studies find that psychosis is connected to anandamide imbalance (Leweke, 2012).