Brain cells are sensitive to chemicals, substances in the blood and other brain fluids.
Persons that use or abuse drugs get the feeling from drugs by exposing their brain cells to chemicals that are not usually found in the brain. The brain knows that it is not working correctly when these chemicals affect it. If a person continues to use a drug, including marijuana, the brain cells try to adapt to the new chemicals around them so that they can continue to function. This may explain why the memory of chronic marijuana users improves with abstinence. Health aspects of cannabis.