What are the benefits of smoking ganja or weed?

Answer 1

This is a hotly-contested issue. I'm going to try to take a middle road between the Reefer Madness crowd and, say, NORML.

The most thoroughly well-documented beneficial effects are that it acts to reduce nausea and stimulate appetite (the well-attested "munchies"). Many antineoplastic (cancer) drugs causenausea and loss of appetite, so it can be useful in conjunction with chemotherapy for cancer, or for other disorders with those symptoms.

It's also known to lower intraocular (eye) pressure, and so is sometimes used as an alternative treatment for glaucoma.

There are a lot of other claimed benefits, but the evidence for these is not as strong. One complicating factor is that almost no one disputes that marijuana use is enjoyable, which calls into question how much of the claimed benefits are real and how much of it is a, you'll pardon the expression, "smoke screen" by proponents who primarily want to use it for recreational purposes (the promotion of hemp fiber for manufactured goods has the same problem; while the variety grown for fiber is different from the variety grown for drug content, they look similar from the air and since the drug variety is shorter it's possible to hide it in fields of the taller fiber variety).

Less beneficial, but well documented, side effects include reddening of the eyes, dryness of the mouth, atypical temperature sensations (a "hot" or "cold" feeling on the skin despite the ambient temperature not changing), and increased heart rate.

Some studies have also shown that marijuana has a deleterious effect on short-term memory, impaired motor skills, and feelings of anxiety or paranoia (these are fairly well attested even in popular culture among those who themselves use the drug).

There's also concern that it may cause heart problems and mental disorders (evidence on the latter, at least, is mixed at best; heavy use is associated with mental disorders, but it's not known whether marijuana use causes the disorders, exacerbates them in susceptible individuals, or if they're both effects of some other underlying cause).

Finally, marijuana smoke has been found to contain carcinogens, the same as tobacco smoke. However, while a British study concluded marijuana smoking was indeed a cancer risk, a US study found that when cofactors (for example, many marijuana smokers also smoke tobacco) were taken into account marijuana use posed no significant increase in risk.