Currently, the compound is being studied for its potential in treating psychosis and schizophrenia. It is also being studied, in combination with THC, as an add-on treatment to improve outcomes in patients with certain types of cancer. Sign Up NowGet this delivered to your inbox, and more info about our products and services. The FDA on Monday also issued warning letters to 15 privately owned CBD companies for illegally advertising their products as treating diseases, selling products as dietary supplements and adding CBD to human and animal foods. There are still "a number of question regarding CBD's safety — including reports of products containing contaminants, such as pesticides and heavy metals — and there are real risks that need to be considered," Abernethy said.