In 2017, warnings that smoking weed can kill you sound like ridiculous anti-drug propaganda. A new study, however, has taken a serious look into the link between heavy cannabis use and suicidal ideation. Researchers at Louisiana State University found that daily weed smokers reported having more suicidal thoughts than less frequent users. They also found that heavy smokers feel more alienated and more burdensome to others than people who smoke less often.
The study surveyed 209 undergraduates who had used cannabis in the past month before the study took place. (A large number of the participants, 76.1 percent, happened to be women.) To assess the frequency of their cannabis use, the researchers asked the students to fill out a standardized measure called the Marijuana Use Form.
The participants also filled out the Interpersonal Needs Questionnaire, which accesses two indicators that have been shown to predict suicidal ideation—perceived burdensomeness and thwarted belongingness—under the Interpersonal-Psychological Theory of Suicide (IPTS). IPTS holds that when an individual experiences both perceived burdensomeness and thwarted belongingness they will start to desire suicide. The researchers wanted to look at these factors because, they note, previous research has shown that social problems such as "losing friends" or "neglecting family" are linked to heavy cannabis use.
In addition, they completed a questionnaire which directly asked participants to rate the statement "I had thoughts of suicide" in the past two weeks from one (not at all) to five (extremely).
The researchers then divided the smokers by how frequently they smoked, based on their answers to the Marijuana Use Form and analyzed the groups' answers to the later questionnaires. Thirty-nine participant were classified as daily users. They found that "daily users reported significantly greater current SI [suicidal ideation] than less frequent cannabis users," according to the study. They also found that daily users also reported greater thwarted belongingness and perceived burdensomeness. In other words, they more likely to say they felt like they were a burden to others and they felt more alienated.
The study notes that one of its big limitations is that it is cross-sectional, which means it can't tell us the directionality of the cannabis' association with suicidal ideation. The researchers do not claim to say that cannabis makes you suicidal; it could be that people who have suicidal thoughts are more likely to self-medicate with heavy cannabis use. Additionally, 88 percent of the participants also drank alcohol, which could also play a role.
Deciphering the link "will be an important next step to test whether daily cannabis use leads to perceived burdensomeness and/or thwarted belongingness or whether these IPTS components lead to daily cannabis use," the researchers write.