Long-term effects of minimum legal drinking age laws on marijuana and other illicit drug use in adulthood

Examining the Intended and Unintended Impacts of Raising a Minimum Legal Drinking Age on Primary and Secondary Societal Harm and Violence from a Contextual Policy Perspective: A Scoping Review

Raising a minimum legal drinking age (MLDA) has generated interest and debate in research and politics, but opposition persists. Up to now, the presentation of impacts focussed on effectiveness (i.e., intended impact); to our knowledge, no literature syntheses focussed on both intended and unintended impacts. A systematic scoping review was conducted in which a search strategy was developed iteratively and literature was obtained from experts in alcohol research and scientific and grey databases. Ninety-one studies were extracted and analysed using formative thematic content analysis. Intended impacts were reported in 119 units of information from the studies (68% positive), forming four paths: implementation, primary and (two) on secondary societal harm and violence. Unintended developments were reported in 43 units of information (30% positive), forming five themes. Only eight studies reported on implementation. Furthermore, a division between primary and secondary paths and the use of a bridging variable (drinking patterns in analyses or methodology) was discovered. These results provide an insight into how well legislation works and can be used to discover or implement new means of curbing underage drinking and alcohol-related violence and harm. They also offer valuable starting points for future research and underline the importance of considering unintended developments.

Does cannabis complement or substitute alcohol consumption? A systematic review of human and animal studies

BACKGROUND

Whether alcohol and cannabis complement or substitute each other has been studied for over two decades. In the changing cannabis policy landscape, debates are moving rapidly and spill-over effects on other substances are of interest.

AIMS

update and extend a previous systematic review, by: (a) identifying new human behavioural studies reporting on substitution and/or complementarity of alcohol and cannabis, and (b) additionally including animal studies.

METHODS

We replicated the search strategy of an earlier systematic review, supplemented with a new search for animal studies. Search results were crossed checked against the earlier review and reference lists were hand searched. Findings were synthesised using a narrative synthesis.

RESULTS

Sixty-five articles were included (64 in humans, one in animals). We synthesised findings into categories: patterns of use, substitution practices, economic relationship, substance use disorders, policy evaluation, others and animal studies. Overall, 30 studies found evidence for substitution, 17 for complementarity, 14 did not find evidence for either, and four found evidence for both.

CONCLUSIONS

Overall, the evidence regarding complementarity and substitution of cannabis and alcohol is mixed. We identified stronger support for substitution than complementarity, though evidence indicates different effects in different populations and to some extent across different study designs. The quality of studies varied and few were designed specifically to address this question. Dedicated high-quality research is warranted.

The Impact of the Minimum Legal Drinking Age on Alcohol-Related Chronic Disease Mortality

BACKGROUND

The minimum legal drinking age (MLDA) of 21 has been associated with a number of benefits compared to lower MLDAs, including long-term effects, such as reduced risk for alcoholism in adulthood. However, no studies have examined whether MLDA during young adulthood is associated with mortality later in life. We examined whether individuals exposed to permissive MLDA (<21) had higher risk of death from alcohol-related chronic disease compared to those exposed to the 21 MLDA. Because prior work suggests that MLDA affects college students differently, we also conducted conditional analyses based on ever having attended college.

METHODS

Data from the 1990 through 2010 U.S. Multiple Cause-of-Death files were combined with data on the living population and analyzed. We included individuals who turned 18 during the years 1967 to 1990, the period during which MLDA varied across states. We examined records on death from several alcohol-related chronic diseases, employing a quasi-experimental approach to control for unobserved state characteristics and stable time trends.

RESULTS

Individuals who reported any college attendance did not exhibit significant associations between MLDA and mortality for the causes of death we examined. However, permissive MLDA for those who never attended college was associated with 6% higher odds for death from alcoholic liver disease, 8% higher odds for other liver disease, and 7% higher odds for lip/oral/pharynx cancers (odds ratio [OR] = 1.06, 95% confidence interval [CI] [1.02, 1.10]; OR = 1.08, 95% CI [1.03, 1.13]; OR = 1.07, 95% CI [1.03, 1.12], respectively).

CONCLUSIONS

The 21 MLDA likely protects against risk of death from alcohol-related chronic disease across the lifespan, at least for those who did not attend college. This is consistent with other work that shows that the long-term association between MLDA and alcohol-related outcomes is specific to those who did not attend college.

Alcohol and cannabis use among college students: Substitutes or complements?

AIMS

Economists debate whether changes in availability of alcohol or cannabis are positively or negatively related to changes in use of the other substance. Implicit in these arguments are two competing, individual-level hypotheses-that people use alcohol and cannabis either as complements or substitutes for one another. This is the first study to test these hypotheses using micro-longitudinal data on individuals' alcohol and cannabis use on a given evening.

METHODS

United States college students who use alcohol and cannabis (n=876) were selected from a larger sample who participated in a 30-day online daily diary study. At baseline, students reported their proclivity to use alcohol/drugs to cope with stress. Each day students reported their level of alcohol use from the prior evening as well as whether they had used cannabis.

RESULTS

Evening levels of alcohol use and mean levels of alcohol use positively predicted the likelihood of evening cannabis use, results indicative of complementary use. This relation, however, was moderated by coping style, such that students who were more likely to use alcohol/drugs to cope were less likely to use cannabis as their evening or mean alcohol use levels increased, results indicative of substitution.

CONCLUSIONS

Substance-using college students showed evidence for complementary alcohol and cannabis use at both the within- and between-person levels. Students with a proclivity toward using alcohol/drugs to cope, however, showed evidence of substitution. These findings suggest that studies based on economic theories of substance use should take into account individual differences in substance use motives.