Legalizing marijuana hasn’t increased teenage use, study finds

According to a new study, legalization of medical use of marijuana in some US states hasn’t resulted in a rise in the numbers of teenagers using it in the country. This finding left the study’s authors utterly surprised and will most likely encourage individuals and authorities planning to relax the law in other parts of the country and the world.

In the past 19 years i.e. since 1996, the District of Columbia (DC) and a total of 23 US states have legalized medicinal applications of marijuana or cannabis. In addition, in DC and states like Alaska, Washington, Colorado and Oregon recreational use of weed is also permissible.

Since the time state governments first started to consider legalizing medical cannabis, critics have been expressing their concerns about the effects of such a step. According to them, legalization of cannabis may result in increase in its use, particularly among teenagers. The study discussed here was based on this assumption of the critics.


The said study was led by Dr. Deborah Hasin of the Columbia University Medical Center in New York; Dr. Hasin teaches epidemiology at the university. During the study, Dr. Hasin and her colleagues analyzed 24 years of data collected from over 1 million adolescents in 48 contiguous US states. The results presented by the analyses didn’t substantiate the concerns of the critics.

The study that has been published in the widely read journal Lancet Psychiatry suggests that cannabis use by teenagers was already higher in states where medical applications of weed got legalized. Change in law, according to the research team under Dr. Hasin, didn’t result in rise in numbers.

During the research, the team of researchers analyzed data gathered during an annual national study called “Monitoring the Future”. This annual study collects facts from 50,000 students aged between 13 and 18 years and studying in the eighth, tenth and twelfth grade.

When analyzing, the team found that there has been no rise in cannabis use among these teenagers even after considering state, individual and school-level factors which can have an effect of marijuana use. Some examples of the factors considered include private or public school, ethnicity, age, etc.

When speaking about the findings of the study, Dr. Hasin said that this study has successfully presented the strongest evidence ever to prove that cannabis use by adolescents doesn’t increase due to legalization of medical marijuana in their state of residence.

However, she said that the fact that use of weed by teenagers was already higher in states where medical marijuana has been legalized is quite worrying. She feels so because use of weed in early adolescence might result in long term adverse effects. According to Dr. Hasin, it is extremely important to identify factors leading to such high popularity of weed among teenagers.

Another alarming revelations made by the study was that out of the youngest pupils surveyed i.e. the 8 graders, use of cannabis was found to drop. According to the study’s authors, the drop in cannabis use has been observed only among the youngest adolescents as older students might have already developed fixed views about the drug before its medical legalization. The authors said that the same thing didn’t happen in case of the younger students as they couldn’t view cannabis as a recreational drug once its medical use became legal.

Another possible reason behind drop in marijuana use among eight graders, according to the authors, could be more robust and vigilant stance of the parents.