Marijuana 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.
For example, a study from New Zealand conducted in part by researchers at Duke University showed that people who started smoking marijuana heavily in their teens and had an ongoing marijuana use disorder lost an average of 8 IQ points between ages 13 and 38. The lost mental abilities didn’t fully return in those who quit marijuana as adults. Those who started smoking marijuana as adults didn’t show notable IQ declines. 
The popularity of edibles also increases the chance of harmful reactions. Edibles take longer to digest and produce a high. Therefore, people may consume more to feel the effects faster, leading to dangerous results.
Points to remember
- Marijuana refers to the dried leaves, flowers, stems, and seeds from the Cannabis Sativa or Cannabis Indica plant.
- Marijuana contains the mind-altering chemical THC and other related compounds.
- People use marijuana by smoking, eating, drinking, or inhaling it.
- THC over-activates certain brain cell receptors, resulting in effects such as:
- altered senses
- changes in mood
- impaired body movement
- difficulty with thinking and problem-solving
- impaired memory and learning
- Marijuana use can have a wide range of health effects, including:
- hallucinations and paranoia
- breathing problems
- possible harm to a fetus’s brain in pregnant women
- There aren’t any reports of teens and adults dying from using marijuana alone, but marijuana use can cause some very uncomfortable side effects, such as anxiety and paranoia and, in rare cases, extreme psychotic reactions.
- Marijuana use can lead to a substance use disorder, which can develop into an addiction in severe cases.
- No medications are currently available to treat marijuana use disorder, but behavioral support can be effective.
Gang Alternative, Inc. operates the Youth Excellence Program, the Urban Partnership Drug-Free Community Coalition, and the Urban Partnership for Success Collaborative to reduce substance use and abuse in our community.
Information provided from the National Institute on Drug Abuse.
Go to https://www.drugabuse.gov/publications/drugfacts/marijuana to learn more.
 Meier MH, Caspi A, Ambler A, et al. Persistent cannabis users show neuropsychological decline from childhood to midlife. Proc Natl Acad Sci U S A. 2012;109(40):E2657-E2664. doi:10.1073/pnas.1206820109.