Taken collectively, exposure to cannabis is neither a necessary nor a sufficient cause of schizophrenia—similar to cigarette smoking being neither necessary nor sufficient to cause lung cancer. More likely, cannabis exposure is a component or contributing cause that interacts with other known (genetic, environmental) and unknown factors, culminating in schizophrenia. In the absence of known causes of schizophrenia, however, the role of component causes such as cannabinoid exposure should remain a focus of further study. Further work is necessary to identify the factors that underlie individual vulnerability to cannabinoid-related psychosis and to elucidate the biological mechanisms underlying this risk.
