A highly biased study was recently published (2014) in the New England Journal of Medicine titled Adverse Health Effects of Marijuana Use. It concluded that chronic marijuana use causes several serious consequences. This persnickety publication was written by author Dr. Nora D. Volkow, lead investigator, and director of the National Institute on Drug Abuse.[ref]N Engl J Med 2014; 370:2219-2227June 5, 2014[/ref]

Perhaps I’m naive but I think anyone working for NIDA would not be painting any “drugs of abuse” in a nice light even if they were proven harmless. Try to view this study as no more than a scientifically gilded opinion piece.

Much of the ammo used to bash marijuana hails from this publication and several others of the same ilk.

Let’s stroll through the major points of the study.

8 “Facts” About Cannabis

Their results included the following:

1. Approximately 9% of people who experiment with the substance will become addicted.

2. One in 6 of those who start using marijuana as teenagers will become addicted.

3. Cannabis withdrawal syndrome is real and can make cessation difficult.

4. Marijuana addiction increases the risk for using other illicit drugs.

5. In addition, adults who regularly smoked the substance during adolescence have impaired neural connectivity in areas that involve alertness, awareness, learning, and memory compared with those who have never smoked marijuana.

6. They also have less functional connectivity in areas that include processing habits and routines and inhibitory control, as well as a significant decline in IQ.

7. Regular use of cannabis has also been associated with an increased risk for depression and anxiety; it has been linked to psychoses (especially in those with a preexisting genetic vulnerability), and it exacerbates the illness in patients with schizophrenia.

8. Immediate and long-term exposure to the substance has been found to substantially impair driving ability. But studies on whether it contributes to lung cancer are unclear.

From the same article in the New England Journal of Medicine we have listed in the review highlights from Medscape.org which states:

Addiction to marijuana is a real phenomenon. Cannabis withdrawal syndrome is characterized by irritability, insomnia, dysphoria, and anxiety. Approximately 9% of individuals who experiment with marijuana will become addicted. However, this rate increases to 17% among people who began using marijuana during adolescence, and up to half of individuals who smoke marijuana daily are addicted.

Marijuana use during early adolescence is associated with worse school performance and a higher risk of dropping out of school.

Solid epidemiologic [associations again] evidence exists that marijuana acts as a gateway drug to the use of other, more harmful illicit drugs. Animal models suggest that THC, the main active ingredient of marijuana, can prime the brain for enhanced responses to other drugs.

Heavy marijuana use has been associated with unemployment, criminal behavior, lower income, and reduced satisfaction with life.

Marijuana is the most commonly cited illicit drug in promoting motor vehicle crashes. A meta-analysis found that using marijuana increased the risk for a motor vehicle crash approximately twofold. Other research has found that the risk for motor vehicle crashes after the use of marijuana is similar to that of persons beyond the usual legal limit of blood alcohol while driving.

Dear reader, wherever you see the term “associated” in the sentences above you should remember that there is no proof that marijuana does anything of the sort.

These studies by definition are weaker than randomized, double-blinded, placebo controlled clinical trials-the gold standard. As such they only suggest that there is a possibility that pot could be causing these problems but for proof we need the gold standard.