Age-related trends in cannabis use in Australia. Findings from a series of large nationally representative surveys

Trends in alcohol, MDMA, methylamphetamine and THC in injured and deceased motor vehicle drivers and motorcyclists over a decade (2010-2019) in Victoria, Australia

BACKGROUND

Driving under the influence of alcohol and other drugs contributes significantly to road traffic crashes worldwide. This study explored trends of alcohol, methylamphetamine (MA), 3,4-methylenedioxy-N-methylamphetamine (MDMA) and Δ9-tetrahydrocannabinol (THC), in road crashes from 2010 to 2019 in Victoria, Australia.

METHODS

We conducted a cross-sectional analysis using data from the Victorian Institute of Forensic Medicine and Victoria Police, examining proscribed drug detections in road crashes. Time series graphs per substance explored indicative trends and comparisons between road users. Negative binomial regression models, with robust SEs and adjusted for exposure (kilometres travelled, Victorian licence holders), modelled the incidence rate ratio, with a Bonferroni-adjusted α=0.007 for multiple comparisons.

RESULTS

There were 19 843 injured drivers and 1596 fatally injured drivers. MA had the highest prevalence (12.3% of fatalities and 9.1% of injured drivers), demonstrating an increase over time. Overall, 16.8% of car drivers and motorcyclists tested positive for one or more drugs, with 14% of crashes involving a blood alcohol concentration (BAC)≥0.05%. MA and THC were the most common drugs in fatalities. Between 2015 and 2019, MA was detected in 27.9% of motorcyclist fatalities, followed by THC (18.3%) and alcohol ≥0.05% (14.2%), with similar but lower frequencies among injured motorcyclists. Alcohol detections (≥0.05% BAC) in fatalities declined, but increased in injured motorcyclists and car drivers until plateauing in 2017. THC detections rose among injured drivers until 2018, detected in 8.1% and 15.2% of injured and fatal drivers, respectively. MDMA-positive driving decreased among injured drivers and remained stable at ~1% of fatalities.

CONCLUSIONS

Despite enhanced road safety measures in Victoria, drug-driving persists, indicating a need for revised prevention strategies targeting this growing issue.

Alcohol and Drug Consumption among Drivers before and during the COVID-19 Pandemic: An Observational Study

Restrictions imposed during the COVID-19 pandemic might have changed recreational habits. In this study, the results of toxicological tests for alcohol and drugs in blood were compared among drivers stopped at roadside checks in the periods before (1 January 2018 to 8 March 2020) and after the lockdown measures (9 March 2020 to 31 December 2021). A total of 123 (20.7%) subjects had a blood alcohol level above the legal limit for driving of 0.5 g/l, 21 (3.9%) subjects tested positive for cocaine, and 29 (5.4%) subjects positive for cannabis. In the COVID-19 period, the mean blood alcohol level was significantly higher than in the previous period. Cannabis use, which was more frequent among younger subjects, was statistically associated with cocaine use. There has also been a quantitative increase in alcohol levels in the population with values above the legal limits, indicative of greater use of alcohol in the population predisposed to its intake.

An age-period-cohort analysis of trends in psychedelic and ecstasy use in the Australian population

AIM

To test the age, cohort, and period effect on past-year use trends in psychedelic drugs and ecstasy.

METHOD

Data were from a repeated cross-sectional nationally representative household survey in Australia conducted every three years between 2001 and 2019. An age-period-cohort model was used to test the effect of age, birth cohort, and period on past year psychedelic and ecstasy use. Participants were between 18 and 80 years old at the time of the survey. The total sample size was 149,296 (Mean age = 45.8; 56% female). Past-year use of psychedelics and ecstasy were the key outcome variables. There were six birth cohorts that were derived in each survey: 1936-50, 1951-60, 1961-70, 1971-80, 1981-90, and 1991-2001. There were seven periods that coincided with survey years: 2001, 2004, 2007, 2010, 2013, 2016 and 2019. Age was treated as continuous.

RESULTS

Past-year use of both psychedelics and ecstasy decreased with age, b = -0.87, 95% CI [-1.14, -0.61] and b = -0.84, 95% CI [-1.08, -0.60]. For ecstasy, while there was significant variation across periods (p < .001), there was no obvious trend. There was a significant birth cohort effect (p < .001), with prevalence increasing from the 1936-50 cohort, peaking in the 1971-80 cohort and then decreasing in the 1991-2001 cohort. For psychedelics, there was significant variation across periods (p < .001) with an upward trend. There was a significant birth cohort effect (p < .001), with prevalence increasing from the 1936-50 cohort to similarly high prevalence for the three most recent cohorts (1971-80, 1981-90, 1991-2001).

CONCLUSION

There were strong cohort and period effects in trends in the use of psychedelic and ecstasy.