How Would a Gateway Hypothesis Work?Supporters of this hypothesis for drug abuse point to two underlying conditions that could result in certain substances making a person more vulnerable to using other drugs or alcohol. 1) A gateway drug would presumably alter neuropathways in the brain. Research has shown that animals that begin to use certain types of substances early in life are at an increased likelihood to develop addictive behaviors related to other substances. When these animals are examined postmortem, findings indicate that some regions of their brain are altered. Also, the results of these experiments are similar to observational data seen in humans. 2) There is an interplay of genetics and environment. Twin studies in humans found a significant genetic component related to drug abuse. This component was exhibited in those who abuse multiple substances. Therefore, certain intrinsic factors may contribute to the altering of neuropathways, and also account for the gateway hypothesis. Scientists who study drug abuse have identified several environmental and individual factors that may be associated with polysubstance abuse. Thus, the gateway theory presumes that the interaction of intrinsic factors with personal experience may lead to situations that support its hypothesis.
Evidence Supporting the Gateway Drug TheorySome research suggests that the use of marijuana is likely to precede abuse and addiction to other substances. For example, one study found that adults who reported using marijuana during the first phase of the survey were more likely than their marijuana-free counterparts to develop an alcohol use disorder within three years. Marijuana use has also been associated with other substance use disorders, such as nicotine addiction. But there is more to be considered—many other factors may contribute to substance use, including the following:
- Neighborhood and community environment
- Level of parental supervision in youth
- Unique individual characteristics, including biology and experiences