Once you have smoked long enough, like any supplement.. The neurotransmitters in your brain stop naturally producing the effects it has on the brain. Once you stop, your brain might not ever produce it again. That's why people need higher doses of ANY DRUG to get the desired effect. Heroin, crack, steroids are the worst. Marijuana if used long enough will be needed in order to be "normal". I am very wise. Listen to me..