Long-term use of either cannabis or cannabis-based drugs impairs memory say researchers. The study has implications for both recreational users and people who use the drug to combat epilepsy, multiple sclerosis and chronic pain. They found that mice exposed to the drug long-term had “significant … memory impairments” and could not even discriminate between a familiar and novel object.
There is little understanding of the potential negative side effects of long-term cannabinoid exposure, though it is already known that heavy, regular cannabis use increases the risk of developing mental health problems including psychosis and schizophrenia.

More and more people are using the drug long-term due to its legalisation in several countries, while more potent varieties are available for recreational users.

Researchers from Lancaster and Lisbon Universities studied the effects of the cannabinoid drug WIN 55,212-2 in mice and found that:

• Long-term exposure impairs learning and memory in the animals
• Brain imaging studies showed that the drug impairs function in key brain regions involved in learning and memory
• Long-term exposure to the drug impairs the ability of brain regions involved in learning and memory to communicate with each other, suggesting that this underlies the negative effects of the drug on memory