In an experiment to find out whether marijuana is a gateway drug adolescent rodents were put to the test. The study found that any exposure that happened at an early stage of development like adolescence decreased the brain’s reaction to dopamine and may result in seeking for rewards later as the adolescent develops. If these results are generalized or limited to human beings, then they could be useful in explaining why early marijuana users have an increased exposure or tendency toward drug abuse or addiction to other psychoactive drugs later in their lives. This conclusion has been reported by a number of epidemiological surveys.
The conclusion is also in line with different animal tests that show that THC is able to ‘prime’ the brain to enhance its response to other drugs. As an example, a rat that was previously given THC also showed an increased behavioral response, this happened not only when it was exposed to THC some more but also when other drugs were introduced to it like morphine. This is a phenomenon referred to as cross sensitization.
Therefore the result findings are what we use to bring out the consistent notion that marijuana is indeed a gateway drug. However, we should make it clear from the beginning that it is not all people who consume marijuana from any form who also go on to use other harder drugs. Another factor is that this tendency, cross sensitization is not only limited to marijuana. Other drugs including nicotine and alcohol are also able to prime the brain to create a heightened response for other drugs including marijuana. In fact alcohol and nicotine are substances used initially, before one moves on to more concentrated harmful substances.
It is also worth noting that there are also other factors such as biological mechanisms and an individual’s social environment that are important to the individual’s potential to abuse different drugs.