Keepers of the gateways

Among the arguments against cannabis use and legalization is that it serves as a “gateway drug,” one that increases a person’s risk of trying other “harder” drugs. 

The National Institute on Drug Abuse cites several studies on animals that seem to show how THC (tetrahydrocannabinol, the main psychoactive component of cannabis or marijuana) “primes” the brain for enhanced responses to other drugs. For example, one study revealed how rats who had previously been administered THC had a heightened response to drugs like morphine, a relationship called “cross-sensitization.”

But it’s not just marijuana that gets that label. Alcohol and tobacco have also been fingered as gateway drugs. And all three, in various studies, have been shown to create cross-sensitization.

A 2017 Columbia University study concluded that smoking and alcohol were also gateways to cocaine addiction. When researchers coaxed rats to drink alcohol for two hours a day over 11 days, and then periodically introduced the little rodents to cocaine, the rats were more likely to seek out the harder drug. Durable chemical changes in the rats’ brains “resulted from mechanisms that turn genes on and off in the brain’s reward centers, creating a ‘permissive environment’ for addiction,” said the study’s authors. 

Previous studies had found a similar relationship with nicotine. “Our results were as predicted according to the gateway hypothesis,” said one investigator. “People use nicotine and alcohol before using cocaine.” Apparently, so do rats.

So, all three substances — cannabis, alcohol, and tobacco — have gateway potential. But not everyone buys into the “gateway hypothesis.” 

An alternative theory holds that vulnerability to drug abuse has more to do with social environment and availability. An oft-cited 2016 study found that for 54 percent of 12th graders, the first drug they tried was alcohol; for 32 percent it was tobacco, and for only 14 percent it was marijuana. But alcohol and cigarettes generally are easier for young first-time users to obtain. Which drug “came first” doesn’t clarify cause and effect. Are kids who “start early” on one drug more likely to try other drugs later, or are kids who are predisposed genetically or environmentally to try harder drugs more likely to experiment with alcohol early?

The real gateway to hard drug use and addiction is not a substance at all, however. It is virtue, or rather, its deficiency. A lack of prudence results in bad choices. A lack of temperance leads to overconsumption. The best way to develop these virtues is to form one’s conscience well and to practice self-denial in order to master one’s passions and selfish impulses. After all, we are humans, not rats. We are endowed with a rational intellect and free will for a purpose. 

That’s not to equate cannabis with alcohol and suggest it should be legal — which would be imprudent (see article on Cannabis and Catholics). But it does serve to underscore that the primary key to avoiding drug abuse or addiction — and so many other social ills — lies in attention to personal virtue.