Alcohol and Marijuana Use Predict Suicide Attempts Among Adolescents Prior to Inpatient Hospitalization

Background/Purpose: Suicide is the second leading cause of death among adolescents, accounting for one in ten deaths in this age group. Although previous research demonstrates strong evidence for alcohol use and mixed evidence for marijuana use as risk factors for suicide attempts (SAs), little research has examined the relationship between alcohol and marijuana use and SAs on a daily level. These relationships are especially important to understand among adolescents psychiatrically hospitalized for a suicidal event, as they are at high risk for suicide attempts and death. Therefore, the purpose of this study was to examine how alcohol and marijuana use predict the odds of SAs over time, controlling for hospitalizations, the presence of a suicide plan, sexual orientation, race, and age.

 

Methods: Participants were recruited from an inpatient psychiatric unit in the northeastern US. and included 50 adolescents (80% female; M_age=15.8) hospitalized following a suicide plan or attempt who endorsed past month alcohol use. Past 90-day SAs, alcohol use, and marijuana use were measured using the Timeline Follow Back Calendar (TLFB). The TLFB collects alcohol and marijuana consumption information using a calendar format with temporal cues to assist in recall of days and quantity when alcohol and marijuana were used, and can be used to simultaneously recall suicide attempts. The Hausman test indicated differences in the between and within effects for alcohol use, marijuana use, hospitalizations, and suicide plans; thus, they were estimated separately in the model.

 

Results: Of the participants, 70% endorsed at least one SA over the 90 days. There were 4,497 time-person observations nested within 50 participants. The random effect model demonstrated that the between effect of alcohol use (OR=7.39, p<.05) and the within effect of marijuana use (OR=1.06, p<.05) significantly increased the odds of a SA on any given day. However, the within effect of alcohol use and the between effect of marijuana use did not predict the odds of SA.

Conclusions/Implications: This study found that alcohol and marijuana use both have an effect on the odds of attempting suicide over time. Specifically, when looking at the 90 days prior to inpatient psychiatric care, those who drank alcohol were 6.4 times more likely to attempt suicide compared those who did not drink, on any given day. In addition, there was a 6% increase in the odds of attempting suicide on a day when a participant used marijuana, compared to a day when they did not use marijuana. The effect of alcohol use on SAs was only significant when comparing adolescents against one another, while marijuana use had a more significant effect when comparing use within oneself. These findings support prior research on the deleterious effect of alcohol use on suicide attempts and adds to the dearth of research on the relationship between marijuana and suicide, which will become evermore critical to understand as marijuana use continues to increase among adolescents in the context of current US policy changes.