Jenny Williams

Cannabis, Alcohol and Cigarettes: Substitutes or Complements?

This paper uses individual level data from the National Drug Strategy Household Surveys to estimate the price responsiveness of participation in cannabis, alcohol and cigarette use. In addition to own price effects, we estimate cross price effects and the impact of decriminalizing cannabis use. We find that participation is responsive to own prices. There is some evidence that cannabis is a substitute for alcohol and a complement to cigarettes, and that alcohol and cigarettes are complements. The liberalization of cannabis laws in South Australia may have led to a temporary increase in cannabis use among the over-30 age group. Copyright 2001 by The Economic Society of Australia.

Does alcohol consumption reduce human capital accumulation? Evidence from the College Alcohol Study

It is often conjectured that a significant cost of youthful drinking is the future labour market consequences of having accumulated a lower stock of human capital. While several studies have investigated the effect of youthful drinking on the quantity of human capital stock accumulated, measured by years of education completed or high-school graduation, this paper investigates the effect of alcohol consumption on the quality of human capital stock accumulated as measured by college students GPA. Using data from the Harvard School of Public Healths College Alcohol Study, the indirect effect of the quantity of alcohol consumed on GPA is estimated through hours spent studying as well as the direct effect. Results show that the net total effect of alcohol consumption on GPA is negative for the sample of college students, and that the main effect is via a reduction in the hours spent studying. This finding confirms that high levels of alcohol consumption have an overall negative consequence for academic achievement, and hence future labour market outcomes.

Why Parents Worry: Initiation into Cannabis Use by Youth and Their Educational Attainment

In this paper we use individual level data from the Australian National Drug Strategy Household Survey to study the relationship between initiation into cannabis use and educational attainment. Using bivariate duration analysis we find that those initiating into cannabis use are much more likely to dropout of school, and that the reduction in years of education depends on the age at which initiation into cannabis occurs. We also find that the impact of cannabis uptake is larger for females than males.

An Analysis of the Crime as Work Model: Evidence from the 1958 Philadelphia Birth Cohort Study

This paper builds on the neoclassical model of time allocation introduced by Gronau (1977), and revisited in the context of crime as work by Grogger (1998), by disaggregating the types of capital characterizing an individual to include social and criminal capital in addition to traditional human capital. The combination of juvenile and adult arrest data, labor market, and background variables make the sample we analyze, the 1958 Philadelphia Birth Cohort Study, especially well-suited to examining the relative importance of these aspects of individual capital. We find that human capital measures such as number of years of schooling have a significant impact on criminal choice in adulthood. We find that social capital measures such as peer influences during youth are also key predictors of criminality.

Cannabis Use and Suicidal Ideation

Globally, suicide has emerged as the second leading cause of death among youth aged 10-24 years old. In order to better understand the causes of this phenomenon, we investigate the relationship between suicidal ideation and cannabis use. Our empirical analysis is based on a 30-year longitudinal study of a birth cohort. We find that intensive cannabis use - at least several times per week - leads to a higher transition rate into suicidal ideation for males. We find no evidence that suicidal ideation leads to cannabis use for either males or females.

Is the Relationship between Socioeconomic Status and Health Stronger for Older Children in Developing Countries

Recent research on the relationship between child health and income in developed countries reveals a positive gradient that is more pronounced for older children, suggesting that the impact of income upon health accumulates. This article examines whether the same is true in a developing country. Using data from the Indonesian Family Life Survey on children aged 0 to 14 years, we find that although low income adversely affects health, its impact does not differ by age. This finding is robust to the use of both subjective and objective health measures, controlling for selective mortality, the use of alternative measures of households’ resources, and the inclusion of indicators of health at birth and parental health. One explanation for the constancy of the health-income relationship that we explore is the dominant role played by acute illness in determining the general health status of children in a developing-country context compared with the more central role played by chronic conditions in developed countries.

Study habits and the level of alcohol use among college students

This paper draws on the 1997 and 1999 waves of the College Alcohol Study to examine the effect of alcohol consumption on the study habits of college students. A generalized least squares estimation procedure is used to account for the potential correlation in the unobserved characteristics determining drinking behavior and study habits. Our results reveal that failing to account for the endogeneity of the level of drinking leads to an over‐estimate of its effect on the likelihood that a student misses a class or gets behind in school. We also find differential effects of drinking on the study habits of freshman students and their upper‐year counterparts.

Cannabis Use and Mental Health Problems

This paper investigates whether cannabis use leads to worse mental health. To do so, we account for common unobserved factors affecting mental health and cannabis consumption by modeling mental health jointly with the dynamics of cannabis use. Our main finding is that using cannabis increases the likelihood of mental health problems, with current use having a larger effect than past use. The estimates suggest a dose response relationship between the frequency of recent cannabis use and the probability of currently experiencing a mental health problem.

The Effects of Cannabis Use on Physical and Mental Health

This paper investigates whether cannabis use affects physical and mental health. To do so, information on prime aged individuals living in Amsterdam in 1994 is used. Dutch data offer a clear advantage in estimating the health impacts of cannabis use because the legal status of cannabis in the Netherlands ensures that estimates are free from confounding with the physical and psychological effects of engaging in a criminal activity. Accounting for selection into cannabis use and shared frailties in mental and physical health, the results suggest that cannabis use reduces the mental wellbeing of men and women and the physical wellbeing of men. Although statistically significant, the magnitude of the effect of using cannabis on mental and physical health is found to be small.

College Students' Use of Cocaine

After experiencing a period of rapid decline between 1986 and 1994, cocaine use is once again on the rise in the United States. The increased prevalence of use among college students is particularly troubling because of its potential impact on human capital acquisition and long-term labor market success. Merging information on the price of cocaine and marijuana from the U.S. Drug Enforcement Agency with data on cocaine use from the College Alcohol Study, we investigate the demand for cocaine in the college population. We find evidence that participation in cocaine use by college students is responsive to changes in the price of cocaine and marijuana and that cocaine and marijuana are economic complements for this population. Further investigation revealed significant differences in the demand for cocaine by those less than age 21 and those at least age 21, years, with the younger age group being more responsive to changes in the price of cocaine. No difference is found, however, in the demand for cocaine across gender.