Marijuana use directly affects the brain — specifically the parts of the brain responsible for memory, learning, attention, decision making, coordination, emotions, and reaction time.
What are the short-term effects of marijuana on the brain?
Heavy users of marijuana can have short-term problems with attention, memory, and learning, which can affect relationships and mood.
What are the long-term effects of marijuana on the brain?
Marijuana also affects brain development. When marijuana users begin using as teenagers, the drug may reduce attention, memory, and learning functions and affect how the brain builds connections between the areas necessary for these functions.
Marijuana’s effects on these abilities may last a long time or even be permanent. This means that someone who uses marijuana may not do as well in school and may have trouble remembering things. 1-3
The impact depends on many factors and is different for each person. It also depends on the amount of tetrahydrocannabinol (THC) in marijuana (i.e., marijuana potency or strength), how often it is used, the age of first use, and whether other substances (e.g., tobacco and alcohol) are used at the same time.
Marijuana and the developing brain
Developing brains, like those in babies, children, and teenagers are especially susceptible to the hurtful effects of marijuana. Although scientists are still learning about the effects of marijuana on the developing brain, studies show that marijuana use by mothers during pregnancy may be linked to problems with attention, memory, problem-solving skills, and behaviour problems in their children.