PHOTO: Smoking pot

TETRAHYDROCANNABINOL (THC), the active ingredient in marijuana, has been on the federal government’s List of Controlled Substances (under hallucinogenic substances) since 1970, when Congress passed the Controlled Substances Act. Over the past 50 years, untold numbers of people have been arrested, fined and jailed in Virginia for selling or smoking “weed”—which is now viewed by a majority of Americans as relatively benign, and less dangerous to human health than a cigarette, an alcoholic drink, or a candy bar.

But just as many states are hurtling headfirst into legalizing marijuana, scientists who actually study its effects on humans have found a troubling correlation that suggests taking a long pause would be a good idea.

A study published in March in The Lancet Psychiatry found “a link between heavy cannabis use and risk of psychosis.” Researchers found “no evidence of an association between less-than-weekly cannabis use and psychosis, regardless of potency.” However, across 11 different study sites, the “prevalence of daily cannabis use in the controls, or prevalence of high potency cannabis use, was correlated with incidence rates for psychosis in the location in question, although cannabis use samples were very small.”

“Given the changing legal status of cannabis across the world, and the associated potential for an increase in use, the next priority is to identify which individuals are at risk from daily potent cannabis use, and to develop educational strategies and interventions to mitigate this,” the study concluded.

According to the National Institute on Drug Abuse, “the strongest evidence to date concerns links between marijuana use and substance use disorders and between marijuana use and psychiatric disorders in those with a preexisting genetic or other vulnerability.”

The Food and Drug Administration has approved certain medications that use purified chemicals derived from the marijuana plant to treat specific illnesses, such as childhood epilepsy. However, the risk of developing psychosis from daily marijuana use is seven times higher for people with a specific genetic variant that involves the neurotransmitter dopamine, according to NIDA. So while “medical marijuana products may play a role in reducing the use of opioids needed to control pain… these products don’t come without risk,” the agency warned.

In Congress, the House Financial Services Committee recently passed “landmark legislation” that would make it easier for businesses that sell marijuana or THC-infused products in states where pot use has been legalized to obtain access to the nation’s banking system. Advocates say that since marijuana use is still illegal under federal law, such businesses are forced to operate on a cash-only basis, which makes them targets for criminals.

Five dispensaries have been approved in Virginia for the sale of medical cannabis, which does not contain THC. Attempts to decriminalize pot possession in Virginia failed again this year, but advocates will no doubt be out in force this election year, pressing candidates for the General Assembly to declare their support for full legalization.

Before they do, candidates should first ask themselves whether a substance whose daily use has been linked to psychosis—defined as the loss of contact with reality—in certain vulnerable individuals should be as easily available in Virginia as a pack of gum without a way to identify those most at risk. Do they really want to promote a substance that may cause severe mental illness in some users?

The current deadly opioid epidemic started when doctors, pharmacists and public officials ignored clear signs of addiction in certain susceptible individuals despite the pharmaceutical companies’ claims that the medications they were peddling were not addictive.

Let’s be sure not to make the same mistake twice.