Cannabis is one of the most abused substances in the world, and it is getting legalized around the world. Consequently, it is crucial to understand its effect on mental health. Its impact on the schizophrenia spectrum needs special attention. Even though cannabis has been around for a long time, its exact effects on schizophrenia. Schizophrenia is a chronic illness affecting approximately 20 million people worldwide. In this review the relationship between cannabis and schizophrenia will be reviewed.