Marijuana is a drug. Marijuana refers to the dried leaves, flowers, stems, and seeds from the Cannabis sativa or Cannabis indica plant. The plant contains the mind-altering chemical THC and other similar compounds. Extracts can also be made from the cannabis plant.

Short-Term Effects of Marijuana on the Brain

When a person smokes marijuana, THC quickly passes from the lungs into the bloodstream. The blood carries the chemical to the brain and other organs throughout the body. The body absorbs THC more slowly when the person eats or drinks it. In that case, they generally feel the effects after 30 minutes to 1 hour.

THC acts on specific brain cell receptors that ordinarily react to natural THC-like chemicals. These natural chemicals play a role in normal brain development and function.

Marijuana over-activates parts of the brain that contain the highest number of these receptors. This causes the "high" that people feel.

Long-term Effects of Marijuana on the Brain

Marijuana also affects brain development. When people begin using marijuana as teenagers, the drug may impair thinking, memory, and learning functions and affect how the brain builds connections between the areas necessary for these functions. Researchers are still studying how long marijuana's effects last and whether some changes may be permanent.

Additional Information

NIDA is the reference for all drug information on this page. For more information on Marijuana, please visit the National Institute On Drug Abuse's (NIDA) website at www.drugabuse.gov/publications/drugfacts/marijuana.

If you or a family member is experiencing a mental health or an alcohol or other drug-related emergency, seek immediate assistance by calling the 24-hour Suicide Prevention, Mental Health/Addiction Crisis, Information and Referral Hotline: (216) 623-6888 or United Way 2-1-1.