During the 1990s and 2000s, opponents of the legalization of marijuana (be it recreational or medical) argued that it served as a "gateway" to harder drugs.
While the gateway hypothesis cannot be entirely ruled out, it is also unlikely to be true. Most people who smoke marijuana do not move on to injecting heroin or snorting cocaine. The likelier explanation is that when people decide to do something rebellious, they begin by picking the "low-hanging fruit," such as alcohol, tobacco, or pot.
Put another way, if a person who uses hard drugs first started with marijuana, that does not mean that marijuana caused him to use those hard drugs. Just because A precedes B does not mean that it can be concluded that A caused B. This is a logical fallacy known as post hoc ergo propter hoc.
And somebody needs to tell the CDC about it.
Dear CDC, E-Cigarettes Are Not a Gateway Drug
In this past week's MMWR, the CDC reported that e-cigarettes were often the most common "introductory tobacco product" among teenagers who use actual tobacco products. But this is misleading for two reasons.
First, as explained above, just because a current smoker first started with e-cigarettes does not mean that e-cigarettes caused that person to smoke. It's probably true that teenage tobacco users also consume alcohol and caffeine. According to the CDC's faulty logic, therefore, we could also conclude that beer and soda are gateway drugs.
Second, labeling e-cigarettes a "tobacco product" is meant to be emotive rather than scientifically accurate. E-cigarettes contain nicotine (which may not be much worse than caffeine) but none of the tar and other chemicals that make cigarette smoke so dangerous. Referring to e-cigarettes as tobacco products is analogous to calling a BB gun a firearm.
The CDC admits in the report, "During the past 3 decades, cigarette smoking among youths has declined substantially." Isn't that the real story here? And given other data which shows that e-cigarettes help smokers quit cigarettes, isn't it perhaps likely that e-cigarettes might have played a role in this decline?
It seems from this report that the CDC is more interested in scaremongering about e-cigarettes than it is celebrating a win for public health. That's a shame.
Source: Hines JZ, Fiala SC, Hedberg K. "Electronic Cigarettes as an Introductory Tobacco Product Among Eighth and 11th Grade Tobacco Users — Oregon, 2015." MMWR 66 (23): 604-606. Published: 16-June-2017. DOI: 10.15585/mmwr.mm6623a2.