Date of Award

May 2020

Document Type


Degree Name

Doctor of Philosophy (PhD)



Committee Member

Michael Makowsky

Committee Member

Jorge L Garcia

Committee Member

Devon Gorry

Committee Member

Robert Fleck


This dissertation is comprised of three essays on various potential determinants of substance use and mental health outcomes of mothers and adolescents. These determinants are important, provided the existing evidence that youth smoking and drinking patterns contribute to using these substances in adulthood. Furthermore, mental disorders during childhood have been shown to persist throughout adulthood and interfere with other later health outcomes. Understanding these contributing factors is crucial as it can inform policies affecting these outcomes and provide additional opportunities for lessening substance use and depressive symptoms, both prevalent public health concerns.

In the first chapter, I explore the impact of the number of children on maternal depression and drug use. There is an extensive theoretical literature identifying the negative effects of the number of children on the outcomes for mothers. While several studies have examined the effects on labor market and physical health outcomes, little research to date has considered effects on mental health and substance use. In order to perform this analysis, I use data from the National Longitudinal Surveys of Youth and a variety of empirical strategies. To address the endogeneity of fertility decisions, I use two natural experiments that exogenously increase the number of children—parity-specific twin births and the gender composition of the first two children. My results provide suggestive evidence that an increase in family size at the third birth parity leads to an increase in a mother's probability of depression. The main findings indicate that a third birth induced by a twin birth or the same-sex composition of the first two children increases a mother's probability of alcohol consumption by about 5.0 percentage points. These estimated effects on alcohol consumption are greater for married mothers. By contrast, I do not find strong evidence of increased marijuana use after the birth of an additional child.

Chapter two shifts in focus from exploring the mother's outcomes to evaluating children's mental health outcomes. A large body of theoretical and empirical research explores the causal effect of the number of siblings on various dimensions of children's outcomes. I estimate the impact of increases in sibship size on children's mental disorders using matched mother-child data from the National Longitudinal Surveys of Youth. Using an instrumental variables technique, my findings provide no substantial evidence in support of the traditional quantity-quality fertility trade-off. By exploiting the panel data and using fixed effects to account for omitted factors, my findings show that an additional younger sibling is detrimental for a child's anxious/depressed index and likelihood of visiting a psychiatrist for a mental disorder. The estimated effects are greater for female and non-black children. This relationship is larger in magnitude in the long-term, as compared to a shorter time horizon.

The third chapter of this dissertation examines an additional potential determinant of substance use—in particular, the establishment of compulsory schooling laws. Over the last three decades, half of all states have altered their compulsory schooling laws by raising the minimum dropout age. While advocates support these policy changes for their proposed educational benefits, an additional positive side effect could be the deterrence of youth substance use. Using national survey data from the Youth Risk Behavior Surveillance System survey, I examine the impact of a higher minimum dropout age on high school students' substance use behaviors using a generalized difference-in-difference empirical strategy. To acknowledge that exposure to a higher minimum dropout age is potentially endogenous, this paper employs a propensity score analysis. The results from this analysis provide some evidence that my baseline estimates are biased. However, there does remain some evidence that exposure to a higher minimum dropout age significantly decreases the number of days high school students drink. Overall, my findings yield evidence that a more strict minimum dropout age leads to a decrease in marijuana use, smoking, and drinking for high school students.



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