Some individuals have been found to have mutations on the CNR1 gene, which is responsible for coding the CB1 receptor (a type of receptor in cells throughout your body that interacts with cannabinoids). Issues with the CNR1 gene can ultimately result in a poorly functioning endocannabinoid system, which is an important variable when figuring out how to use CBD oil.
Cannabidiol is currently a class B1 controlled drug in New Zealand under the Misuse of Drugs Act. It is also a prescription medicine under the Medicines Act. In 2017 the rules were changed so that anyone wanting to use it could go to the Health Ministry for approval. Prior to this, the only way to obtain a prescription was to seek the personal approval of the Minister of Health.