According to the latest drift in Western countries, many lawmakers are trying to formulate policy to legalize the usage of Cannabis in the case of mentally vulnerable populations such as those suffering from depression, paranoia, and excessive anxiety. This particular trend has been due to short term success in the case of mood upliftment. Cannabis derivatives produce effects on both mood and cognitive function, which can be a double-edged sword if not followed with proper dosage. Beneficial effects, however, are limited and studies documenting those and even more meagre. Detrimental effects, especially those suffering from various hallucinating and delusional states, have been reported extensively in the literature. Here in the review article, we have tried to study and summarize various effects of Cannabis as well as Cannabis -derived products in the case of people who have various mental conditions. We have also tried to consider addiction to these substances and hence develop a framework for proper utilization of Cannabis in mentally ill people. Many clinicians are also in a dilemma when prescribing a Cannabis -based product to treat psychotic and mood-based disorders. Hence, a better understanding of the process of Cannabis -based treatment for the vulnerable population is necessary.