Suicidal ideation and substance use among adolescents and young adults: a bidirectional relation?

Abstract

Objective: To examine reciprocal associations between substance use (cigarette smoking, use of alcohol, marijuana, and other illegal drugs) and suicidal ideation among adolescents and young adults (aged 11-21 at wave 1; aged 24-32 at wave 4).

Methods: Four waves public-use Add Health data were used in the analysis (N=3342). Respondents were surveyed in 1995, 1996, 2001-2002, and 2008-2009. Current regular smoking, past-year alcohol use, past-year marijuana use, and ever use of other illegal drugs as well as past-year suicidal ideation were measured at the four waves (1995, 1996, 2001-2002, and 2008-2009). Fixed effects models with lagged dependent variables were modeled to test unidirectional associations between substance use and suicidal ideation, and nonrecursive models with feedback loops combining correlated fixed factors were conducted to examine reciprocal relations between each substance use and suicidal ideation, respectively.

Results: After adjusting for the latent time-invariant effects and lagged effects of dependent variables, the unidirectional associations from substance use to suicidal ideation were consistently significant, and vice versa. Nonrecursive model results showed that use of cigarette or alcohol increased risk of suicidal ideation, while suicidal ideation was not associated with cigarette or alcohol use. Reversely, drug use (marijuana and other drugs) did not increase risk of suicidal ideation, but suicidal ideation increased risk of illicit drug use.

Conclusion: The results suggest that relations between substance use and suicidal ideation are unidirectional, with cigarette or alcohol use increasing risk of suicidal ideation and suicidal ideation increasing risk of illicit drug use.

Keywords: Adolescents; Alcohol use; Drug use; Regular smoking; Suicidal ideation; Young adults.

Figure 1

Figure 1a. Fixed effects model with lagged dependent variables-unidirectional association from current regular smoking to suicidal ideation. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, while not all of them were statistically significant larger than 0. The covariances between fixed effect with current regular smoking at wave 3 and 4 were not significant. IDEA, Suicidal Ideation; SMOKE, Current Regular Smoking. Figure 1b. Fixed effects model with lagged dependent variables-unidirectional association from suicidal ideation to current regular smoking. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, while not all of them were statistically significant larger than 0. The covariances between fixed effect with suicidal ideaiton at each wave and the covariance between suicidal ideaiton at wave 4 and current regular smoking at wave 1 were not significant. IDEA, Suicidal Ideation; SMOKE, Current Regular Smoking. Figure 1c. A nonrecursive model: the reciprocal relations between current regular smoking and suicidal ideation. Note. * p<.05, ** p<.01, *** p<.001. IDEA, Suicidal Ideation; SMOKE, Current Regular Smoking; I, Fixed Effect of Suicidal Ideation; S, Fixed Effect of Current Regular Smoking.

Figure 1

Figure 1a. Fixed effects model with lagged dependent variables-unidirectional association from current regular smoking to suicidal ideation. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, while not all of them were statistically significant larger than 0. The covariances between fixed effect with current regular smoking at wave 3 and 4 were not significant. IDEA, Suicidal Ideation; SMOKE, Current Regular Smoking. Figure 1b. Fixed effects model with lagged dependent variables-unidirectional association from suicidal ideation to current regular smoking. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, while not all of them were statistically significant larger than 0. The covariances between fixed effect with suicidal ideaiton at each wave and the covariance between suicidal ideaiton at wave 4 and current regular smoking at wave 1 were not significant. IDEA, Suicidal Ideation; SMOKE, Current Regular Smoking. Figure 1c. A nonrecursive model: the reciprocal relations between current regular smoking and suicidal ideation. Note. * p<.05, ** p<.01, *** p<.001. IDEA, Suicidal Ideation; SMOKE, Current Regular Smoking; I, Fixed Effect of Suicidal Ideation; S, Fixed Effect of Current Regular Smoking.

Figure 2

Figure 2a. Fixed effects model with lagged dependent variables-unidirectonal associaton from past-year alcohol use to suicidal ideaiton. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, while not all of them were statistically sifnificant larger than 0. The covariances between fixed effect with past-year alcohol at each wave, and the covariances between suicidal ideation at wave 1 with past-year alcohol use at wave 3 and 4 were not sginificant. IDEA, Suicidal Ideation; ALCOHOL, Past-year Alcohol Use. Figure 2b. Fixed effects model with lagged dependent variables-unidirectional association from suicidal ideation to past-year alcohol use. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, while not all of them were statistically sifnificant larger than 0. The covariances between fixed effect with suicidal ideaiton at each wave, and the covariances between suicidal ideaiton at wave 3 with past-year alcohol use at wave 1 were not significant. IDEA, Suicidal Ideation; ALCOHOL, Past-year Alcohol Use. Figure 2c. A nonrecursive model: the reciprocal relations between past-year alcohol use and suicidal ideation. Note. * p<.05, ** p<.01, *** p<.001. IDEA, Suicidal Ideation; Alcohol, Past-Year Alcohol Use; I, Fixed Effect of Suicial Ideation; A, Fixed Effect of Past-Year Alcohol Use.

Figure 2

Figure 2a. Fixed effects model with lagged dependent variables-unidirectonal associaton from past-year alcohol use to suicidal ideaiton. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, while not all of them were statistically sifnificant larger than 0. The covariances between fixed effect with past-year alcohol at each wave, and the covariances between suicidal ideation at wave 1 with past-year alcohol use at wave 3 and 4 were not sginificant. IDEA, Suicidal Ideation; ALCOHOL, Past-year Alcohol Use. Figure 2b. Fixed effects model with lagged dependent variables-unidirectional association from suicidal ideation to past-year alcohol use. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, while not all of them were statistically sifnificant larger than 0. The covariances between fixed effect with suicidal ideaiton at each wave, and the covariances between suicidal ideaiton at wave 3 with past-year alcohol use at wave 1 were not significant. IDEA, Suicidal Ideation; ALCOHOL, Past-year Alcohol Use. Figure 2c. A nonrecursive model: the reciprocal relations between past-year alcohol use and suicidal ideation. Note. * p<.05, ** p<.01, *** p<.001. IDEA, Suicidal Ideation; Alcohol, Past-Year Alcohol Use; I, Fixed Effect of Suicial Ideation; A, Fixed Effect of Past-Year Alcohol Use.

Figure 3

Figure 3a. Fixed effect model with lagged dependent variables-unidirectional assocication from past-year marijuana use to suicidal ideation. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, while not all of them were statistically sifnificant larger than 0. The covariances between fixed effect and past-year marijuana use at each wave were not statisitcally significant. IDEA, Suicidal Ideation; MARI, Past-year Marijuana Use Figure 3b. Fixed effects model with lagged dependent variables-unidirectional association from suicidal ideation to past-year marijuana use. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, and all of them were statistically sifnificant larger than 0, except for the covariance between fixed effect and suicidal ideation at wave 4. IDEA, Suicidal Ideation; MARI, Past-year Marijuana Use. Figure 3c. A nonrecursive model: the reciprocal relations between past-year marijuana use and suicidal ideaton. Note. * p<.05, ** p<.01, *** p<.001. IDEA, Suicidal Ideation; MARI, Past-Year Marijuana Use; I, Fixed Effect of Suicial Ideation; M, Fixed Effect of Past-Year Marijuana Use.

Figure 3

Figure 3a. Fixed effect model with lagged dependent variables-unidirectional assocication from past-year marijuana use to suicidal ideation. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, while not all of them were statistically sifnificant larger than 0. The covariances between fixed effect and past-year marijuana use at each wave were not statisitcally significant. IDEA, Suicidal Ideation; MARI, Past-year Marijuana Use Figure 3b. Fixed effects model with lagged dependent variables-unidirectional association from suicidal ideation to past-year marijuana use. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, and all of them were statistically sifnificant larger than 0, except for the covariance between fixed effect and suicidal ideation at wave 4. IDEA, Suicidal Ideation; MARI, Past-year Marijuana Use. Figure 3c. A nonrecursive model: the reciprocal relations between past-year marijuana use and suicidal ideaton. Note. * p<.05, ** p<.01, *** p<.001. IDEA, Suicidal Ideation; MARI, Past-Year Marijuana Use; I, Fixed Effect of Suicial Ideation; M, Fixed Effect of Past-Year Marijuana Use.

Figure 4

Figure 4a. Fixed effects model with lagged dependent variables-unidirectional association from ever other illegal drug use to suicidal ideaiton. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, all of them were statistically sifnificant larger than 0. IDEA, Suicidal Ideation; ILLD, Ever Other Illegal Drug Use Figure 4b. Fixed effects model with lagged dependent variables-unidirectional association from suicidal ideation to other illegal drug use. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, all of them were statistically sifnificant larger than 0, except for the covariance between fixed effect and suicidal ideation at wave 4. IDEA, Suicidal Ideation; ILLD, Ever Other Illegal Drug Use. Figure 4c. A nonrecursive model: the reciprocal relations between ever other illegal drug use and suicidal ideation. Note. * p<.05, ** p<.01, *** p<.001. IDEA, Suicidal Ideation; ILLD, Ever Other Illegal Drug Use; I, Fixed Effect of Suicial Ideation; O, Fixed Effect of Other Illegal Drug Use.

Figure 4

Figure 4a. Fixed effects model with lagged dependent variables-unidirectional association from ever other illegal drug use to suicidal ideaiton. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, all of them were statistically sifnificant larger than 0. IDEA, Suicidal Ideation; ILLD, Ever Other Illegal Drug Use Figure 4b. Fixed effects model with lagged dependent variables-unidirectional association from suicidal ideation to other illegal drug use. Note. * p<.05, ** p<.01, *** p<.001. All the covariances among exogenous variables were specified in the model, all of them were statistically sifnificant larger than 0, except for the covariance between fixed effect and suicidal ideation at wave 4. IDEA, Suicidal Ideation; ILLD, Ever Other Illegal Drug Use. Figure 4c. A nonrecursive model: the reciprocal relations between ever other illegal drug use and suicidal ideation. Note. * p<.05, ** p<.01, *** p<.001. IDEA, Suicidal Ideation; ILLD, Ever Other Illegal Drug Use; I, Fixed Effect of Suicial Ideation; O, Fixed Effect of Other Illegal Drug Use.