Why parents worry: Initiation into cannabis use by youth and their educational attainment

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Abstract

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.

Introduction

One of parents’ greatest fears is that their child will become involved with drugs. Underlying this fear is the belief that drug use could lead to poor educational attainment, subsequent failure in the labor market, and without a good job to anchor their lives, an unhappy future. Viewed within a human capital framework, this scenario may find resonance. For example, drug use could lead teenagers to substitute time spent under the influence of drugs for time spent studying, resulting in poor academic achievement and an early exit from education. This is particularly a concern with cannabis because initiation into its use typically occurs during the teenage years, coinciding with the timing of critical decisions about investment in formal education, both at the extensive and intensive margins. There is, therefore, potential for youthful cannabis use to have a long lasting affect through its impact on the individual’s stock of human capital. This paper investigates the extent to which this is the case by examining how the age of initiation into cannabis use effects subsequent educational attainment.

There is substantial evidence that early cannabis use is associated with lower levels of education (Macleod et al., 2004). What is less well understood is the extent to which this association reflects the causal impact of cannabis use on education outcomes. Associations will not reflect causal effects if, for example, those who self-select into cannabis use differ from those who do not use cannabis in ways that also impact on their academic achievement (selection on unobservables). For example, cannabis users may be more risk loving or discount the future more heavily than non-users and these attributes could also lead them to leave school early. A further issue in identifying the causal impact of cannabis uptake is that poor educational attainment may be both a cause and a consequence of youthful initiation into cannabis (reverse causality). For example, individuals who have low academic ability may leave school early. With less supervision from adults and more free time than those in school, early school leavers may have greater opportunity to start cannabis use. The presence of either selection on unobservables or reverse causality will render cannabis use endogenous to decisions regarding education. If unaccounted for, this endogeneity will lead to inconsistent estimates of the effect of cannabis use on education. Given the obvious objections to using an experimental approach, economics is particularly well placed to address these issues and hence obtain reliable estimates of the impact of youthful drug use on educational attainment.

Despite this, there are only a handful of relevant studies in the economics literature. These studies, reviewed in the following section, find that drug use during high school reduces the number of years of education completed by between 0.2 and 1 year. None of the previous studies, however, investigate the role of the age at which initiation occurs, nor do they consider whether the effect of cannabis use differs across gender. Thus, there is no evidence on whether initiation into cannabis use at age 14 is more or less damaging in terms of educational outcomes than initiation at age 17, or whether the negative effect is the same for males and females. The aim of this paper is to provide answers to these questions. Knowledge about the relative impact of uptake at different ages and across gender is useful from a policy perspective because it can help in targeting strategies that aim to minimize the harm associated with cannabis use.

In this paper, we adopt a bivariate duration model to investigate the impact of the age at which initiation into cannabis use occurs on the probability of leaving formal education.1 We find that the age at which initiation occurs matters in terms of educational attainment and that its effect differs across gender. More specifically, we find that uptake of cannabis before the age of 18 for males, and before the age of 20 for females, leads to a reduction in their expected years of completed education and that this reduction is greater for those who initiate earlier. Moreover the magnitude of the effect is larger for females than males.2 While our data are not rich enough to allow an investigation into why initiation into cannabis use during adolescence has a negative effect on educational attainment, previous studies may provide some insights. Early initiation into cannabis use has been shown to lead to higher levels and longer duration of use by Pudney (2004) and Van Ours and Williams (2007a), respectively. Further, Pacula et al. (2005) reports that it is frequent persistent use that leads to lower educational attainment. Therefore, it may be that starting cannabis use at younger ages leads to heavy persistent use, and it is this mode of use that has a deleterious effect on education.

The rest of this paper is laid out as follows. Section 2 reviews economic studies that investigate the impact of early cannabis use on educational attainment. Section 3 describes the data used in this paper. Section 4 contains the econometric set-up and results for the empirical analysis. Section 5 concludes with a discussion of our findings.

Section snippets

Literature review

The focus of this review is on studies from the economics literature, and particularly those which empirically address the potential endogeneity of cannabis use in decisions about formal education. For a wider review of research on the relationship between drug use and education, see Chatterji (2006) or Pacula et al. (2005).

The economics literature on the relationship between youthful cannabis use and education is limited and relies solely on data from the US. The first two published studies

Australian National Drug Strategy Household Survey

This research draws on information collected in the 2001 Australian National Drug Strategy Household Survey (NDSHS). The NDSHS is managed by the Australian Institute of Health and Welfare on behalf of the Commonwealth Department of Health and Ageing. It is designed to provide data on awareness, attitudes and behavior relating to licit and illicit drug use by the non-institutionalized civilian population aged 14 years and older in Australia. A multistage stratified design was used to generate

Econometric set-up

Previous research by Chatterji (2006), Pacula et al. (2005) and Register et al. (2001) find that early cannabis use reduces educational attainment. This raises the question of whether the adverse consequences of uptake at age 12 are the same as at age 16, and whether this effect persists at older ages. These questions relate to the issue of the timing of events, which is naturally handled within a duration model framework. Therefore, in this section, we model transitions into cannabis use and

Discussion

In this paper, we investigate the impact of initiation into cannabis use by youth on their educational attainment. Our contribution to the literature is threefold. First, we use the dynamic framework of hazard rate analysis while previous studies rely on an instrumental variable approach. Second, using this dynamic framework we show that the magnitude of the effect of initiation into cannabis use depends on the age of first use. Our third contribution is to show that there are differences

Acknowledgments

We gratefully acknowledge support from the Australian Research Council; grant number DP0770580 and thank two anonymous referees for their very helpful comments on a previous version of the paper.

References (26)

  • P. Chatterji

    Illicit drug use and educational attainment

    Health Economics

    (2006)
  • C. Godfrey

    Evidence-based illicit drug policy: the potential contribution of economic evaluation techniques

    De Economist

    (2006)
  • D.W. Hommer et al.

    Evidence for a gender-related effect of alcoholism on brain volumes

    American Journal of Psychiatry

    (2001)
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