One of the biggest problems with presenting research on cannabis is that there is not very much of it. Research, that is—there is plenty of cannabis. Currently, many physicians agree that marijuana is safe enough to temporarily alleviate the symptoms of certain medical conditions, but the safety of recreational use is poorly understood.
There is, however, some useful data.
One common misconception about cannabis is that it has no addictive properties. In fact, 9% of people who use marijuana will become heavily dependent on it, and that number is as much as 50% among those who use marijuana daily. The American Psychiatric Association defines cannabis use disorder in its DSM-5; it affects more Americans than any other drug use disorder. The rate was up to 1.7% of the population 10 years ago, which predates current potencies and legalization.
Tolerance builds up rapidly with frequent use. As much as eight times the normal dose is needed for regular users; this is often used as an argument that marijuana is a gateway drug. However, there are also well-understood strategies for overcoming this to some extent. Examples include increased exercise, starting with smaller doses in the morning, and sometimes taking days away from marijuana.
There is no concrete link between cannabis smoke and cancer, but there are carcinogens in the smoke, as well as many chemicals which are also found in tobacco. An analysis published in Scientific American last year based on data from 5,000 Americans found no decline in lung function among people who smoked joints two or three times a month over two decades. The authors say, however, that they did not assess the effects of daily use on lungs.
Marijuana does not appear to have any significant negative neurological side effects when used responsibly by adults.
However, for those under age 25, the brain is still developing, and use in this group is linked with lower IQ scores later in life: up to eight points of loss. Worse, combining alcohol and marijuana can be downright dangerous.
Younger drinkers do not often understand the delayed effects of alcohol and may drink until the onset of those effects, which means they will more easily drink to the point of alcohol poisoning. Once marijuana is added to that equation, the cognition of those effects appears to decline further, leading to even more drinking. Add to this that both alcohol and marijuana are depressants, and that the latter inhibits the very nausea that may extract some of the alcohol, and it is little wonder there are increasing numbers of alcohol poisoning cases resulting in either permanent debilitating neurological damage or death in which marijuana is a factor.
All this aside, marijuana is perhaps the safest intoxicant available. On its own, not used with any other intoxicants or drugs and not laced with anything, it is quite nearly impossible to consume THC at a lethal level. Marijuana is the most commonly used drug in the world as well as in the U.S., with over 19 million people in the United States reported as having used cannabis in the last month. The key, as with many things, may lie in moderation and a generally healthy lifestyle.
By Whitman Spitzer