Why is marijuana not a gateway drug

Entry drug cannabis?

Image: www.pixelio.de / chris

The term “gateway drug” hides the assumption that the consumption of hashish or weed or cannabis in general more or less inevitably leads to the consumption of other stronger drugs such as heroin. Cannabis is therefore the first step towards drug addiction. This simple thesis is now considered refuted. But current research on early entry into cannabis cosum has rekindled the discussion. According to this, changes in the brains of adolescents would possibly lead to a basic susceptibility to opiate consumption after all.

The thesis of the "pacemaker function"

The thesis of the so-called pacemaker function has its origin in the observation that the majority of opiate addicts started with cannabis when they “entered” into the use of illegal drugs. Among other things, it was suspected some kind of biochemical mechanism, which in the case of cannabis means that users have to increase the dose and cannabis will soon no longer be sufficient to satisfy the desire for more. The well-known psychiatrist Karl-Ludwig Täschner once put it this way: “With hashish, increasing the dose alone is only enough for a short time to further increase the effect. Instead, new drugs with stronger effects must appear. "

Today the thesis of a simple mechanism applies, which sets in motion a kind of automatism towards stronger drugs when using cannabis, as refuted. If the thesis were correct, millions of people in Germany would have to switch to drugs such as opiates or cocaine in view of the spread of cannabis. That is undoubtedly not the case. Around 23 percent of all Germans over the age of 18 have used cannabis at some point, but less than one percent of all adults are currently using other drugs. Of the totality of cannabis users, only a very small percentage switch to regular use of other drugs. Incidentally, most of them also stop using cannabis at some point.

If one were to cite the fact that most opiate addicts started with hashish or marijuana as an argument in favor of the gateway drug cannabis, one could just as easily claim, according to drug researchers Dieter Kleiber and Karl-Arthur Kovar, “that a cold inevitably leads to pneumonia Because almost every pneumonia is preceded by a cold. ”Both authors examined the risks of cannabis consumption in 1998 as part of an extensive expertise and stated that the pacemaker thesis was not tenable based on the scientific knowledge of the time.

Alcohol and tobacco first

Nevertheless, it cannot be dismissed that there is one more or less fixed order when trying out psychoactive substances. Studies have been able to provide clear evidence. Almost all users of heroin, cocaine or ecstasy had started with hashish or marijuana. Consistently, however, the consumption of alcohol and tobacco would have to be included when considering a chronological sequence. The first intoxication experiences are usually made with alcohol and in almost all cases tobacco smoking comes first before the first hashish cigarette. It is still not entirely clear why this sequence seems to be so fixed.

"Image" of a drug

In all likelihood, the social framework conditions play an important role. Kleiber and Kovar emphasize in their expertise that the order in which certain drugs are tried depends on the current “image” of a substance and cultural fashions. The authors consider the argument that the illegality of cannabis creates a proximity to other illegal substances and thus promotes the transition to be unlikely. Cannabis use is now subject, at least among young people, to a certain "everyday" and "normalization", in other words: for many young people hashish or smoking weed is nothing special, and when acquiring the illegal drug cannabis they do not automatically come into contact with other drugs, since there are mostly different sources.

Influence of the circle of friends

After all, research was able to show that it is mainly people of the same age, i.e. friends, who have an important influence on drug use. As a rule, it is not the "bad dealer" who seduces young people. Rather, it is People from the circle of friends who initiate drug use and ensure availability. Ultimately, however, the causal chains when starting and continuing drug use are complex and cannot be reduced to the influence of a substance. Other factors such as the motivation underlying the consumption, psychological problems and general living conditions must also be taken into account.

Early entry particularly problematic

Now that it appeared that the thesis of the "Gateway drug" cannabis has already been filed, have been in recent years new research have been published, which take up the topic again. What earlier studies hadn't taken into account: Young people who smoke their first joint at a young age may be more at risk than others who join later. As a rule, consumption before the age of 16 and occasionally before the age of 18 is defined as an early start.

In order to reduce methodological problems of the many influencing factors to a minimum, an international research team led by the US scientist Michael Lynskey Studies on twins carried out, i.e. genetically very similar people who also grew up under the same socialization conditions. The team found that twins who smoked weed before the age of 18 were 7.4 times more likely to use party drugs later than their brothers and sisters who were over 18 when they first jointed. The team of authors concludes from this that cannabis may increase the likelihood of consuming other drugs after all, at least if it is first used before the age of 18. That sounds quite plausible in view of the twin study method. What Michael Lynskey and his two colleagues did not include in the analysis and what they themselves have to admit as a flaw in their research article is the fact that twins can have different friends. And they can not only consume hashish, but also other drugs such as ecstasy or amphetamines.

Brain changes from early cannabis use

The question that remains is what is different in adolescents than in adults when they consume hashish or cannabis in general. To answer this question, researchers have recently been using findings from brain research. In an animal experiment it could be shown that the brain can change permanently at a young age when cannabis is consumed. Rats that were given THC, the active ingredient in cannabis, in adolescence showed changes in the brain's reward center. An increased concentration of opioid receptors could be detected, i.e. the docking points for endogenous opiates - or also exogenous ones like heroin. It means that Cannabis use in adolescence possibly one on a biological level increased susceptibility to the use of other drugs how opiates entail.

However, doubts about the simple transferability to humans are certainly appropriate. While the rats (compulsorily) received their "substance" from the investigator, the initiation and continuation of consumption in humans is determined by many factors, for example - as mentioned above - by the circle of friends. Even if changes in brain chemistry are detected, it is still unclear how sustainable these are and how this interacts with other factors.


In summary, it can be said that the path to drug use and its possible hardening of behavior is characterized by complex causes and processes. Hashish or weed are just one factor among many and certainly not in view of the latest study results the Gateway drug.