It is not uncommon for someone with a marijuana use disorder to have co-occurring disorders. Two that are common include other substance use disorders and mental illnesses. All of these illnesses have risk factors in common, which is one important reason they co-occur. The phenomenon may also be explained by the fact that many people with mental illnesses, like depression, turn to substances, like alcohol, as a form of self-medication.
Long-term marijuana use can also trigger or contribute to physical health conditions. These include respiratory conditions similar to those caused by cigarette smoking: chronic bronchitis or emphysema. Cannabinoid hyperemesis syndrome is a condition that long-term users may develop and that causes severe cycles of nausea and vomiting that can lead to dangerous dehydration.