Cannabis today is the same plant that has been cultivated and used for thousands of years. However, due to the large number of varieties, the level of THC (the main neuroactive ingredient) differs widely. Interestingly, cannabis tested in jurisdictions where it is illegal tends to be stronger. Why? When access to a particular substance is sporadic, risky and limited, both consumers and producers are incentivised to use or sell higher potency material.
During alcohol prohibition in the United States, beer and cider were largely replaced by spirits and hard liquor; easier and more profitable to transport. When access is regulated and controlled, there’s a wider variety of potencies, like cannabis with virtually no trace of THC, but high in CBD. CBD is known to be therapeutic (without the euphoria).
Different methods of ingestion can also affect the strength of cannabis. Infused edibles, for example, can have a stronger effect and last longer than smoking cannabis. It’s important to regulate dosage, remembering it can take up to one hour before a cannabis edible takes effect.