The effects of marijuana use on the human body are complex and incompletely understood.
Acute Side Effects
Most of the perceptible side effects of marijuana use are a result of the body’s reaction to the psychoactive THC cannabinoid. THC stimulates or “activates” specific psychological responses generally, but not always, associated with euphoria and relaxation.
The results of a major, long-term study into marijuana use and lung health reveal no substantive link between cannabis use and respiratory diseases like lung cancer. Additionally, lifelong marijuana users had no significantly increased risk of breathing problems.
Although marijuana smoke contains a number of carcinogens findings from a limited number of well-designed studies do not suggest an increased risk for the development of either lung or upper airway cancer from light or moderate use. However, the evidence is mixed when it comes to the carcinogenic risks of heavy, long-term marijuana users, according to this study.
Scientists simply do not know the overall impact of marijuana on cardiovascular health. Researchers in California, Pennsylvania, and New York analyzed dozens of studies into the effects of cannabis on heart health, high cholesterol, and high blood pressure. Their analysis revealed more problems with previous studies than answers.
However, scientists do agree that marijuana use increases the heart rate anywhere from 20 to 50 beats per minutes for up to 3 hours. Other studies have indicated links between marijuana use and increased blood pressure and hypertension. But these findings were contradicted by further studies.
Multiple studies have concluded that the non-psychoactive cannabinoid CBD imparts the significant neuroprotective effects of marijuana. This effect can shield nerve cells from damage and deterioration, making medical marijuana a promising drug for treating a range of neurological diseases.
The relationship between marijuana use and mental health is not fully understood. On the one hand, research suggests that cannabis can help treat certain mood disorders. The effects of marijuana use on memory and cognition may also help patients suffering from PTSD forget traumatic memories.
On the other hand, some studies suggest that cannabis use can contribute to the onset of or exacerbate existing mental health problems. According to the WHO, marijuana use can make schizophrenia and other psychoses worse. Some marijuana users also report experiences of acute anxiety and paranoia as a side effect of the drug.