Google Trends Can Help Track Marijuana Use and Perceptions of Risk: Study

The online tool Google Trends may be able to help track the public’s use of marijuana, a new study suggests. The researchers say the tool can also be used to gauge growing interest in other drugs.

The study found a significant correlation between state Google Trends marijuana search volume and current marijuana use among youth and adults in those states.

The researchers from Washington University School of Medicine in St. Louis compared search terms about marijuana in Google Trends in 2011. The tool, based on Google Search, shows how often a particular search term is entered relative to the total search-volume across various regions of the world, and in various languages.

They looked at 20 popular search terms including “marijuana,” “cannabis,” “bong,” “roll a joint,” “THC,” and “blunts.” For words associated with marijuana that can have more than one meaning, the researchers looked at specific phrases. For instance, instead of “weed” or “pot,” they searched for phrases such as “smoke weed” or “grow pot.”

“We looked at regional trends—differences across states in marijuana search terms, and then we compared those with marijuana abuse and dependence rates, people’s perception of availability of marijuana, and their perceptions of marijuana risks,” said study co-author Melissa Krauss, Senior Statistical Data Analyst in the Department of Psychiatry.

They compared the volume of marijuana-related searches with data on marijuana use and attitudes from the National Survey on Drug Use and Health.

In addition to a link between marijuana-related search volume and current marijuana use, the researchers also found a moderate correlation between Google Trends search volume and people’s belief that occasional marijuana use is not of great risk.

The findings will be presented at the upcoming College on Problems of Drug Dependence annual meeting.

Marijuana searches tended to be more frequent in the West and Northeast than in the Midwest and parts of the South. Although the data was collected before recreational marijuana was legalized in Colorado and Washington state, those states had among the highest rates of marijuana-related searches on Google. Currently, those two states have the most marijuana-related searches, Krauss observed.

Google Trends has been used for other health-related research, most notably tracking influenza. Recently, a study found Google’s flu-tracking service greatly overestimated the number of flu cases in the United States. Krauss says the tool may be more useful for tracking health risk behaviors. “While Google Trends won’t replace other surveillance tools, it can be a quick and easy way for public health officials and researchers to track marijuana-related interest,” she noted. “It also has the potential to be used to track real-time interest in other substances.”