People use cannabis for the effects that it produces. Some people also use the drug to cope with another condition, such as depression or other psychological disorders. Marijuana has been used as a painkiller for many years, and it is legal in some places for medical use. The issue of whether cannabis drugs should be legalized is related in part to the medical uses of marijuana.

Signs of cannabis addiction include an increased level of tolerance for the drug, where a person needs to use more and more to reach the desired effect. Using the drug for a longer period than planned may also signify dependence, as do unsuccessful attempts to quit using the substance. Over time, cannabis dependence can interfere with a person's social activities and important relationships. It may also negatively affect responsibilities such as work or school. Some people know they are addicted, desire to stop or cut back, yet continue to use the drug despite its causing physical or emotional problems.

Treatment for substance abuse includes stopping use of the drug. Withdrawal symptoms can be uncomfortable, but are not dangerous. They may last for a day to a week, and can include irritability, moodiness, anxiety, difficulty sleeping, and occasionally tremors, nausea, and vomiting. Treatment options depend on the individual and the severity of the addiction. Support groups may be helpful, such as Narcotics Anonymous. Individual counseling or more formal treatment options may also be an option.