1. New York State Suicide Prevention Conference
September 19th, 2017
Subtypes of substance users and suicide behaviors: An adolescent risk profile
Michael A. Lindsey, PhD, MSW, MPH
Director, McSilver Institute for Poverty Policy and Research
Constance and Martin Silver Professor of Poverty Studies
NYU Silver School of Social Work

2. All speakers, associated with this continuing education activity, have indicated that they have no financial arrangement or affiliation with any commercial entity whose products, research or services may be discussed in this presentation.

3. Key Questions
How can we use secondary data to examine the risk/profile of adolescents who engage in suicidal behaviors?
What type of substance use behaviors in youth may lead to increased risk for suicide?

4. Prevalence
Among U.S. youth age 15-19, suicide is the second leading cause of death (19.2% of deaths) National Vital Statistics Reports; Vol 65 No 5. Hyattsville, MD: National Center for Health Statistics, 2016
From 2008 to 2015, the number of youth aged 5-17 admitted to children’s hospitals for suicidal thoughts or self-harm more than doubled Plemmons et al., 2017

5. Cultural & Gender Considerations
Suicide is not only a “White” phenomenon
Increasing rates among ethnic minority youth, especially Black boys and Latina adolescents
In 2014, males aged 15 to 19 were approx. 3x more likely than females to die by suicide (CDC, 2015)

6. Suicide Rates for Adolescents Ages 15–19 Years, 1975–2015
*Suicide rates for adolescents have been rising since 2007
Source: CDC - National Vital Statistics System

7. Suicide and Substance Use
Studies have found that up to 70% of adolescents who completed suicide were drug or alcohol users Miller et al., 1991
Odds of attempting suicide are x greater for adolescents (age 13-18) with substance disorders Nock et al., 2013

8. Types of Suicidal Behaviors
Suicidal Ideation: Serious consideration or thoughts of suicide attempt
Suicide Plan: Making a plan about how one would attempt suicide
Suicide Attempt: A non-fatal, potentially injurious behavior with an intent to die
* As captured by the Youth Risk Behavior Survey (YRBS)

9. Typologies of Substance Use
Experimentation
Regular use (Daily or Almost Daily)
Abuse
Dependence
Substance Use Disorder

10. Polysubstance use Usage of multiple substances or “joint” usage
Considers the number and types of substances
Correlated with other behavioral health issues in adolescents (i.e. sexual risk behaviors, internalizing symptoms)

11. Methods and Analytic Directions
Background on Dataset and Sample
Step 1: Latent Class Analysis (LCA) on Substance Use Behaviors
Step 2: What is the relationship between Profiles of Substance Users and Suicidal Behaviors?
Multinomial Logistic Regression

12. Dataset 2015 Youth Risk Behavior Survey (YRBS)
National epidemiological assessment of Youth Risk Behavior Surveillance System (YRBSS)
9th – 12th grade students of all public, Catholic, and other private school; in 50 States and the District of Columbia
Three-stage cluster sample design, representative sample
Estimate national rates of health-related behaviors
School response rate: 125/180 = 69%
Student response rate: 16,624/18,165 = 86%
Overall response rate: 69% * 86% = 60%

13. Sample Final Weighted Sample Size: 15,555 students
Gender: Male (50.7%); Female (49.5%)
Racial/ethnic Distribution:
Black 12.4%
Hispanic/Latino: 22.0%
White: 56.1%
Age:
Majority: 15 years old (26.7%), 16 years old (24.7%), 17 years old (23.5%)

14. Substance Use Indicators Demographic variables
Measures
Constructs
Measures
# of items
Substance Use Indicators
Marijuana Use
Age at Initiation 5
Lifetime and Current (past 30 days) Use
Cigarette Use
No. of cigarette smoked per day in the past 30 days 4
Alcohol Use
Largest No. of alcoholic drinks in a row in past 30 days
Suicidal Behaviors
Suicidal Ideation (0 = No, 1 = Yes) 1
Suicide Plan (0 = No, 1 = Yes)
Suicide Attempt (0 = No, 1 = Yes)
Covariates
Demographic variables
Gender (0=Male, 1=Female) 2
Race/ethnicity (Black, Hispanic/Latino, White) 3
Age (<=12, 13, 14, 15, 16, 17, >=18) 7

15. Analyses Latent Class Analysis (LCA)
Person-centered methodological approach
To identify homogeneous subgroups within heterogeneous population
3-step approach (Asparouhov and Muthén 2013; Vermunt 2010)
Use substance use indicators to estimate the latent class model
Estimation of the most likely class using latent class probabilities
Multinomial logistic regression of the most likely class on demographic/suicidal behaviors variables
The final number of latent classes was determined by the agreement with substantive theory (i.e. dual-factor model), empirical evidence, statistical model fit indices including the Akaike’s Information Criterion (AIC; Akaike 1987), Bayesian Information Criterion (BIC; Schwartz 1978), adjusted BIC (Sclove 1987), Lo–Mendell–Rubin test (LMR; Lo et al. 2001), entropy statistic, and mean responses to each scale by class. The bootstrap likelihood ratio test (BLRT) was not utilized as model fit criteria, as it is unavailable in Mplus with data that have a complex survey structure.

16. Analyses (Con’t)
Unknown latent class – exploration approach estimates one to six latent classes
Account for complex survey design: correcting SE and Chi-square tests based on stratification, unequal probability selection, non-independence observations
Ordered-categorical Outcomes: Weighted Least Squares Means and Variances (WLSMV)
Missing Data: Maximum likelihood with robust SE
Model Fit Criteria: BIC, Adj. BIC, AIC, LMR, Entropy; substantive theory
Mplus version 7.4

17. Fit Statistics and Model Selection
Number of Classes
AIC
BIC
Adjusted BIC
LMR
(p)
Entropy 1
N/A 2
(.00)
0.989 3
(.76)
0.984 4
(.00)
0.963
The adjusted BIC values decreased until a five-class solution was found. The five-class model was examined, but the best log-likelihood value was not replicated even with increased random starts. Therefore, it was not considered for the final model as the solution may not be trustworthy due to local maxima. The LMR of the three-class model was non-significant, meaning the two-class model cannot be rejected, while the LMR of the four-class model was significant again, meaning the three-class model can be rejected in favor of the four-class model. Comparing the four-class model with two-class model, the four-class model had lower AIC, BIC and Adjusted BIC. The entropy of the four-class model was An entropy level 0.6 and higher indicates good class separation (Asparouhov and Muthén 2013). Based on these factors and examination of the substantive meaningfulness of the classes, the four-class model was retained and four lifestyle classes were identified.
* Best log-likelihood value of the five-class model was not replicated even with increased random starts.

18. Classifications Class 1: Nonusers
Class 2: Moderate Polysubstance Users
Class 3: Frequent Polysubstance Users
Class 4: Experimental Polysubstance Users

19. Four-Class LCA Model: Conditional Probabilities of Substance Use by Class
SUBSTANCE USE ITEMS
Latent Class 1
Latent Class 2
Latent Class 3
Latent Class 4
(n =4415, %)
(n = 1635, %)
(n = 3784, %)
(n = 5790, %)
Nonusers
Moderate Users
Frequent Users
Experimenters
Marijuana
Age at Initiation
Never tried marijuana
0.945
0.373
0.132
0.577
8 or 10 years old
0.002
0.030
0.019
11 or 12 years old 
0.003
0.075
0.144
0.040
13 or 14 years old 
0.224
0.311
0.161
15 or 16 or 17 or years older
0.031
0.298
0.281
0.203
Lifetime and Current (30 ds) Use
Never used
1.000
0.000
0.159
No recent use
0.445
0.168
1 or 2 times
0.302
0.232
3 to 9 times
0.173
0.222
More than 10 times
0.080
0.219

20. Four-Class LCA Model: Conditional Probabilities of Substance Use by Class
SUBSTANCE USE ITEMS
Latent Class 1
Latent Class 2
Latent Class 3
Latent Class 4
(n =4415, %)
(n = 1635, %)
(n = 3784, %)
(n = 5790, %)
Nonusers
Moderate Users
Frequent Users
Experimenters
Cigarette
Age at Initiation
Never tried marijuana
0.988
0.740
0.000
0.802
8 or 10 years old
0.002
0.027
0.155
0.030
11 or 12 years old 
0.025
0.150
0.032
13 or 14 years old 
0.081
0.294
0.063
15 or 16 or 17 or years older
0.006
0.127
0.400
0.073
Lifetime and Current (30 ds) Use
Never used
0.964
0.584
0.681
No recent use
0.036
0.416
0.319
1 or 2 times
0.375
3 to 9 times
0.232
More than 10 times
0.393

21. Four-Class LCA Model: Conditional Probabilities of Substance Use by Class
SUBSTANCE USE ITEMS
Latent Class 1
Latent Class 2
Latent Class 3
Latent Class 4
(n =4415, %)
(n = 1635, %)
(n = 3784, %)
(n = 5790, %)
Nonusers
Moderate Users
Frequent Users
Experimenters
Cigarette
No. of cigarette smoked per day
Did not smoke cigarettes in 30 ds
1.000
0.000
Less than 1 – 1 per day
0.487
2-5 cigarettes/day
0.326
6 to more than 20 cigarettes/day
0.187
Alcohol
Age at Initiation
Never drank alcohol
0.986
0.017
0.044
0.085
8 or 10 years old
0.004
0.134
0.222
0.114
11 or 12 years old 
0.129
0.153
0.107
13 or 14 years old 
0.002
0.314
0.330
0.258
15 or 16 or 17 or years older 
0.407
0.250
0.436

22. Four-Class LCA Model: Conditional Probabilities of Substance Use by Class
SUBSTANCE USE ITEMS
Latent Class 1
Latent Class 2
Latent Class 3
Latent Class 4
(n =4415, %)
(n = 1635, %)
(n = 3784, %)
(n = 5790, %)
Nonusers
Moderate Users
Frequent Users
Experimenters
Alcohol
Lifetime and Current (30 ds) Use
Never used
0.921
0.000
0.037
0.106
No recent drink (0 days)
0.079
0.131
0.894
1 or 2 days
0.623
0.271
3 to 9 days
0.332
0.391
More than 10 days
0.045
0.170
Largest No. of alcohol in a row
Did not drink in the past 30 d
1.000
0.159
1-5 drinks/row
0.647
0.281
6-9 drinks/row 
0.272
0.341
10 or more drinks/row
0.080
0.219

23. Demographic Covariates & Suicidal Behaviors
Subtypes of Substance Users & Demographic Covariates/Suicidal Behaviors
Reference Group = Class 4 (Experimenters)
Demographic Covariates & Suicidal Behaviors
Nonusers
Moderate Users
Frequent Users
b (OR) SE p
Age
-0.36 (0.70)
0.04
0.00
0.08 (1.09)
0.07
0.17 (1.19)
0.05
Sex (Male = 1)
0.11 (1.12)
0.10
0.25
-0.01 (0.99)
0.11
0.90
0.51 (1.67)
Black
-0.01 (1.00)
0.20
0.98
0.04 (1.04)
0.18
0.83
-0.61 (0.54)
0.22
0.01
Hispanic/Latino
-0.31 (0.74)
0.17
0.25 (1.29)
0.16
0.12
-0.22 (0.80)
0.13
White
0.12 (1.13)
0.45
0.38 (1.47)
0.19
0.23 (1.26)
0.24
Suicidal Ideation
-0.33 (0.72)
0.14
0.02
0.30 (1.36)
0.53 (1.71)
Suicide Plan
-0.51 (0.60)
-0.11 (0.89)
0.54
0.18 (1.19)
0.32
Suicide Attempt
0.09 (1.10)
0.23
0.69
0.57 (1.78)
1.23 (3.41)

24. Demographic Covariates & Suicidal Behaviors
Subtypes of Substance Users & Demographic Covariates/Suicidal Behaviors
Reference Group = Class 1 (Nonusers)
Demographic Covariates & Suicidal Behaviors
Moderate Users
Frequent Users
Experimenters
b (OR) SE p
Age
0.44 (1.55)
0.03
0.00
0.53 (1.70)
0.05
0.36 (1.43)
0.04
Sex (Male = 1)
-0.12 (0.88)
0.12
0.32
0.40 (1.50)
-0.11 (0.90)
0.10
0.25
Black
0.04 (1.04)
0.20
0.83
-0.61 (0.54)
0.01 (1.01)
0.98
Hispanic/Latino
0.56 (1.75)
0.18
0.09 (1.09)
0.17
0.61
0.31 (1.36)
0.07
White
0.26 (1.30)
0.16
0.11 (1.12)
0.23
0.64
0.45
Suicidal Ideation
0.64 (1.89)
0.87 (2.38)
0.15
0.33 (1.39)
0.14
0.02
Suicide Plan
0.39 (1.48)
0.13
0.68 (1.98)
0.51 (1.66)
Suicide Attempt
0.48 (1.62)
0.21
1.14 (3.12)
-0.09 (0.91)
0.69

25. Demographic Covariates & Suicidal Behaviors
Subtypes of Substance Users & Demographic Covariates/Suicidal Behaviors
Reference Group = Class 2 (Moderate Users)
Demographic Covariates & Suicidal Behaviors
Nonusers
Frequent Users
Experimenters
b (OR) SE p
Age
-0.44 (0.64)
0.03
0.00
0.09 (1.09)
0.05
0.07
-0.08 (0.92)
0.04
Sex (Male = 1)
0.12 (1.13)
0.12
0.32
0.53 (1.69)
0.08
0.01 (1.01)
0.11
0.90
Black
-0.04 (0.96)
0.20
0.83
-0.65 (0.52)
0.21
0.18
Hispanic/Latino
-0.56 (0.57)
-0.47 (0.62)
0.15
-0.25 (0.78)
0.16
White
-0.26 (0.77)
0.10
-0.15 (0.86)
0.17
0.39
-0.38 (0.68)
0.19
Suicidal Ideation
-0.64 (0.53)
0.23 (1.26)
0.14
0.09
-0.30 (0.74)
0.13
0.02
Suicide Plan
-0.39 (0.68)
0.29 (1.34)
0.11 (1.12)
0.54
Suicide Attempt
-0.48 (0.62)
0.65 (1.92)
-0.57 (0.56)

26. Demographic Covariates & Suicidal Behaviors
Subtypes of Substance Users & Demographic Covariates/Suicidal Behaviors
Reference Group = Class 3 (Frequent Users)
Demographic Covariates & Suicidal Behaviors
Nonusers
Moderate Users
Experimenters
b (OR) SE p
Age
-0.53 (0.59)
0.05
0.00
-0.09 (0.92)
0.07
-0.17 (0.84)
Sex (Male = 1)
-0.40 (0.67)
0.12
0.08
-0.51 (0.60)
0.10
Black
0.61 (1.84)
0.32
0.65 (1.92)
0.21
0.61 (1.85)
0.22
0.01
Hispanic/Latino
0.17
0.61
0.47 (1.60)
0.15
0.22 (1.25)
0.13
White
-0.11 (0.89)
0.23
0.64
0.15 (1.16)
0.39
-0.23 (0.79)
0.20
0.24
Suicidal Ideation
-0.87 (0.42)
0.14
0.09
Suicide Plan
-0.68 (0.51)
-0.29 (0.75)
0.19
-0.18 (0.84)
0.18
Suicide Attempt
-1.14 (0.32)
-0.65 (0.52)
-1.23 (0.29)
0.16

27. Summary of Results
Compared to the nonusers’ class, all three other groups had a higher likelihood of engagement in suicidal behaviors
Adolescents in the frequent polysubstance users group exhibited the highest odds of suicidal ideation, suicide plan, and suicide attempt

28. Implications
Screening and prevention programs for adolescents should assess for substance use along the spectrum of lifetime occurrence, current use, and frequency
Education on Risks/Profiles
Moderate and experimental polysubstance users are also at greater risk for suicidal behaviors

29. Thank you!
Michael A. Lindsey, PhD, MSW, MPH Director