- Pregnancy-related risks. Research indicates that children exposed to marijuana while they were in the womb were more likely to experience problems with attention, memory, and problem-solving. Other studies suggest that moderate amounts of THC can pass from a nursing mother to her child through breast milk, which could impact fetal brain development.
- An increased risk of testicular cancer. A few studies show a link between adolescent marijuana use and an aggressive form of testicular cancer.
- Severe cyclic nausea and vomiting. While rare, the condition, known as cannabinoid hyperemesis syndrome, can develop with chronic use.
- Adolescent brain development issues. Some research indicates that regular marijuana use during adolescence—while the brain is still developing—can lead to impaired learning, memory, and impulse control. There is evidence that shows significant differences in brain development when heavy cannabis use starts before age 18. For adults over the age of 18, potentially persistent memory loss and declines in IQ may be linked to chronic or heavy marijuana use, though the evidence isn’t conclusive.
- Psychiatric disorders. Several studies indicate a link between marijuana use and an increased risk of mental health disorders, such as schizophrenia, depression, and anxiety in individuals who are genetically predisposed. In fact, one study found that daily marijuana use, particularly at a young age, makes individuals with specific genes 7 times more likely to develop schizophrenia than people with the gene who do not use the drug. Additionally, marijuana has been shown to worsen symptoms associated with schizophrenia for those who already have the illness.
- Addiction. Marijuana can be an addictive substance. Starting use during adolescence makes eventual compulsive misuse or the development of addiction more likely.
- Increased risk of other substance use disorders. Some research suggests that marijuana use might be associated with an increased risk of future or concurrent addiction to other substances such as alcohol or nicotine.
- Unknown consequences of high potency use. The trend toward higher-potency marijuana could pose additional, yet-unknown risks. Twenty years ago, the average THC content in confiscated marijuana was less than 4%. In 2018, it was more than 15%. Researchers do not yet know the full extent that these higher concentrations of THC will have on the body and brain, especially the developing brain.