Citation

Gripe I, Danielsson AK, Ramstedt M. Addiction 2018; ePub(ePub): ePub.

Affiliation

The Swedish Council for Information on Alcohol and Other Drugs (CAN), Stockholm, Sweden.

Copyright

(Copyright © 2018, John Wiley and Sons)

DOI

10.1111/add.14244

PMID

29679954

Abstract

AIMS: To examine if changes in alcohol consumption are associated with changes in cannabis use among Swedish adolescents in a period of diverging trends, and to investigate if cannabis and alcohol act as complements or substitutes. DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS: Data comprise a nationally representative annual school survey of alcohol and drug habits among Swedish 9^th grade students (15-16 years) covering the years 1989-2016 (n=149 603). Alcohol and cannabis use were measured concurrently and alcohol consumption was measured in liters of 100% alcohol per year. Frequency of cannabis use was transformed into a mean using category midpoints. Autoregressive integrated moving average (ARIMA) time-series analysis was used to estimate the association between cannabis and alcohol use. To elucidate changes in the association during the study period, two sub-periods (2000-2016 and 1989-1999) were analyzed.

FINDINGS: There was a positive and statistically significant association between changes in alcohol consumption and changes in frequency of cannabis use among cannabis users for the period 1989-2016. A 1-liter increase in mean alcohol consumption was associated with a 0.28 increase in frequency of cannabis use (P=0.010). The corresponding increase for the period 1989-1999 was 0.52 (P=0.003). When restricting the analysis to 2000-2016, the association was not statistically significant (P=0.735). When analyzing all adolescents we found no statistically significant association between changes in alcohol consumption and changes in frequency of cannabis use.

CONCLUSIONS: From 1989 to 2016 there appears to be a positive association between alcohol consumption and cannabis among Swedish adolescents who use cannabis. This association seems to have become weaker over time, suggesting that alcohol and cannabis are neither substitutes nor complements among Swedish adolescents and that the recent decline in youth drinking is not associated with the increase in frequency of cannabis use.

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Language: en

Keywords

Adolescents; Alcohol; Cannabis; Complement; Substitute; Time series analysis