evidence: Using marijuana can cause damage to brain cells and result in a number of concurrent symptoms throughout the body. Some effects of heavy marijuana use on the brain may not be reversible. [...] As recreational marijuana use becomes legalized throughout the US, many people now wonder how marijuana affects the brain and whether or not it kills brain cells. Just as years of heavy alcohol, meth, and heroin use can cause some irreversible brain damage, prolonged marijuana abuse can affect the ability of brain cells to convey messages (also known as brain activity). Using marijuana can cause damage to brain cells that results in a number of concurrent symptoms throughout the body. [...] In addition to the above symptoms, synthetic marijuana can be addictive to individuals who take it. After prolonged use of synthetic marijuana, brain cell activity is likely to decline with a concurrent increase in negative physiological symptoms like the ones above.