Reddit has faced some challenges in its efforts to go mainstream and generate more advertising revenue. There is no question that the self-proclaimed “front page of the internet” is home to many distinct topic and interest-based communities.

Until relatively recently, Reddit took a very hands-off approach to the user-generated content on the site, leaving the moderation responsibilities to individuals in the communities themselves. However, as the site matured, the need for codified policies regarding harassment, hate speech and other objectionable content became apparent.

Still, the communities on Reddit aren’t shy about discussing controversial topics, including guns and drugs. ProjectKnow used Google’s BigQuery search to find Reddit posts from 2015 that included drug-related terms such as “cocaine,” “MDMA,” “meth” and “marijuana,” in order to determine which words were more indicative of substance abuse and which Reddit communities discussed drugs and alcohol the most.

More than one-quarter of the content in the r/AskReddit mentioned drugs, making it the No. 1 subreddit for drug-related content. Interestingly, only 14 percent of the content in r/Trees mentioned drugs, while drug mentions only made up 10 percent of the content in r/Drugs.

Overall, marijuana was the most frequently discussed drug on Reddit, and it reflected the widest cross-section of content across communities including r/AskReddit and r/News, according to the data. Alcohol and heroin followed as the second and third most frequently discussed substances. While discussions about marijuana included diverse conversations about legalization, medical use and smoking, alcohol and heroin discussions were often in the context of addiction or quitting.

In fact, a word-correlation analysis of communities focused on specific interests revealed a tendency to discuss relevant drugs. For instance, ecstasy was most mentioned in the MDMA subreddit with the word “brain,” and heroin was most often connected to the word “drug” in r/Opiate. The r/OpiateRecovery community became about how to stop doing heroin, while the r/StopDrinking community often discussed how alcohol use affected their life.

To see more charts and data about how Reddit users upvote and downvote drug related content or when drug mentions peaked on the site, check out the full report.

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