Marijuana affects users mentally in many ways while the user is high, but there is no evidence that it makes any changes to the users mental state when the high wears off. It does not appear possible for people to overdose on marijuana. Most of the physiological harms of marijuana are from the smoke inhaled into the lungs and not THC.
While marijuana is not known to weaken or strengthen the immune system as a whole, people with immune system deficiencies should avoid marijuana smoke because it weakens alveolar macrophages ability to defend against fungi, bacteria, and tumor cells in the lungs. Marijuana smoke does increase the risk of respiratory illness and heavy smokers will have changes in the lining of the respiratory tract.
Medical Marijuana Effects on Users | Fact or Faction
There is no conclusive evidence that marijuana can cause cancer to date, but there is a strong likelihood that further research will find correlations. First time users of marijuana will experience a rapid heart beat for the first few minutes of inhaling, and some users will also have an increase in blood pressure for a few minutes.
First time users will also have a decrease in testosterone or estrogen. Both of these “first time user” effects cease to exist in more experienced users. Pregnant women should avoid inhaling marijuana smoke because it causes a higher mutation rate, but has little effect on the long-term cognitive abilities of the child.
Smoking marijuana (or inhaling any smoke) can cause health problems. But I feel that people that smoke marijuana in moderation are putting themselves at less risk than those that smoke tobacco cigarettes in relative moderation and putting themselves at less risk than those that drink heavily (whether occasional binge drinking or drinking more than a moderate amount on a daily basis). I do not feel that marijuana poses enough threat to make it an unconscionable health problem for our society.
But I do feel that those that smoke marijuana heavily are taking more risks than can be justified. Ultimately I think that people should know the risks involved and make their own decision as to whether or not they are willing to take on those risks.
I think the best way I can end this article is to leave you with someone else’s take on how safe marijuana is on a relative scale. A few years back the United States’ Drug Enforcement Agency had a trial lasting a couple years to determine if medical marijuana was safe enough to be considered for medical use. The case was heard in the court DEA’s own administrative court. After the DEA’s judge read thousands of pages of testimony and heard from dozens of witnesses he declared that marijuana is “one of the safest therapeutically active substances known to man.”