Does using marijuana have long-term effects on the brain?


Whether you’ve tried it yourself, or have been with someone under the influence of marijuana, you know that “getting high” can change how a person thinks and behaves.

Some short-term effects may include immediate changes in thoughts, perceptions and information processing. The cognitive process most clearly affected by marijuana is short-term memory, but this usually disappears as soon as the person is no longer intoxicated.

So, what about long-term effects? There’s no convincing evidence that even heavy, long-term marijuana use by adults permanently impairs memory or other cognitive functions.

Some studies have shown that heavy marijuana use starting in the early teens has an impact on the brain, while other studies have shown no impact. What is clear is that much  more research is needed.

It is strongly recommended that teens not use marijuana as their brains are still developing, and in particular, the part of the brain that controls emotional development can be sensitive.

Learn more about how the brain processes cannabis.


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Shelley's Story

Marijuana: The Facts

The Drug Policy Alliance (DPA) supports information and polices related to marijuana that are grounded in science, compassion, health and human rights. Safety is our top priority, especially when it comes to young people.
This booklet provides brief answers to some of the most commonly-asked questions about marijuana. We hope it will help you better understand this plant and its effects.