Evidence of increasing age of onset of cannabis use among younger Australians

Universal cannabis outcomes from the Climate and Preventure (CAP) study: a cluster randomised controlled trial

Background

The Climate and Preventure (CAP) study was the first trial to assess and demonstrate the effectiveness of a combined universal and selective approach for preventing alcohol use and related harms among adolescents. The current paper reports universal effects from the CAP study on cannabis-related outcomes over three years.

Methods

A cluster randomized controlled trial was conducted with 2190 students from twenty-six Australian high schools (mean age: 13.3 yrs., SD 0.48). Participants were randomised to one of four conditions; universal prevention for all students (Climate); selective prevention for high-risk students (Preventure); combined universal and selective prevention (Climate and Preventure; CAP); or health education as usual (Control). Participants were assessed at baseline, post intervention (6–9 months post baseline), and at 12-, 24- and 36-months, on measures of cannabis use, knowledge and related harms. This paper compares cannabis-related knowledge, harms and cannabis use in the Control, Climate and CAP groups as specified in the protocol, using multilevel mixed linear models to assess outcomes.

Results

Compared to Control, the Climate and CAP groups showed significantly greater increases in cannabis-related knowledge initially (p <  0.001), and had higher knowledge at the 6, 12 and 24-month follow-ups. There was no significant difference between the Climate and CAP groups. While no differences were detected between Control and the CAP and Climate groups on cannabis use or cannabis-related harms, the prevalence of these outcomes was lower than anticipated, possibly limiting power to detect intervention effects. Additional Bayesian analyses exploring confidence in accepting the null hypothesis showed there was insufficient evidence to conclude that the interventions had no effect, or to conclude that they had a meaningfully large effect.

Conclusions

Both the universal Climate and the combined CAP programs were effective in increasing cannabis-related knowledge for up to 2 years. The evidence was inconclusive regarding whether the interventions reduced cannabis use and cannabis-related harms. A longer-term follow-up will ascertain whether the interventions become effective in reducing these outcomes as adolescents transition into early adulthood.

Trial registration

This trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12612000026820) on the 6th of January 2012, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=347906&isReview=true

Electronic supplementary material

The online version of this article (10.1186/s13011-018-0171-4) contains supplementary material, which is available to authorized users.

Time Trends of Cannabis Use Among Treatment-seeking Individuals at Government De-addiction Centers Across India Over a Period of 7 Years

BACKGROUND

Cannabis continues to be the most commonly used illicit psychoactive substance globally. The National Survey in India conducted in the year 2004 also reported it to be the most commonly used illicit substance in the country. Furthermore, it was reported to be the second most commonly used psychoactive substance by the treatment seekers at de-addiction centers in the country.

OBJECTIVES

To assess time trends of cannabis use among treatment-seeking individuals at government de-addiction centers across India over a period of 7 years.

MATERIALS AND METHODS

The study utilized data collected through Drug Abuse Monitoring System across India. The data of treatment seekers from de-addiction centers established under the Drug De-addiction Program, Ministry of Health and Family Welfare, Government of India and supported by the Ministry of Social Justice and Empowerment, Government of India (122 in number) across the country were analyzed.

RESULTS

A total of 107,469 individuals sought treatment from government de-addiction centers over the 7 years (2007-2013) period. With the exception of an aberration for the year 2012, there has been a steady decline in the proportion of treatment seekers who are not current cannabis users. A significantly greater proportion (Chi-square: 586.30, df: 1, P < 0.001) of individuals with current cannabis use alone or along with tobacco (20.4%) tend to have a co-morbid psychiatric disorder as compared to treatment seekers with current use of substances other than cannabis (6.1%).

CONCLUSIONS

It is important to focus on cannabis in clinical service delivery and research in the country.

Incidence trends of cannabis and cocaine use from periodic Spanish general population surveys: effect of standardizing results by age structure

AIMS

This study estimates life-time incidence trends of cannabis and cocaine use over 38 years from general population surveys of drug use (GPSDU) in Spain, taking into account changes of population age structure.

DESIGN

Periodic cross-sectional studies.

SETTING

Eight biennial GPSDU from 1995 to 2009 in Spain.

PARTICIPANTS

Interviewees aged 15-64 years who reported age of first ever cannabis and/or cocaine use between 10 and 64 years between 1971 and 2008.

MEASUREMENTS

Estimates of raw and standardized incidences were calculated as a weighted mean of the incidences from all surveys. Standardization was conducted to take into account changes of population age structure. Incidence trends were extracted applying weighted cubic smoothing splines to incidence estimates.

FINDINGS

For both substances, estimated raw incidence trends increased up until 2000 (rates of 11.5 ± 0.7 and 3.6 ± 0.5 per 1000, respectively, for cannabis and cocaine), and then decreased significantly (in 2008, 9.6 ± 1.2 and 2.7 ± 0.6, respectively). In contrast, standardized rates exhibit a steadily increasing trend up to 2000 (9.0 ± 0.6 and 2.8 ± 0.4), followed by a statistically non-significant increasing trend afterwards (in 2008, 9.5 ± 1.2 and 2.8 ± 0.6). The largest increases of incidence were observed in both male and female subjects aged 15-19 years.

CONCLUSIONS

Using data from Spanish general population surveys of drug use, an apparently decreasing trend of raw incidence rates in both cannabis and cocaine use from 2000 became non-decreasing trends when these rates were standardized. First experiences of cannabis and cocaine use in Spain occur mainly in younger ages (15-19 years).

Changes in cannabis use among young people: impact on mental health

PURPOSE OF REVIEW

The aim of this review was to examine current trends in cannabis use and cannabis use disorder (CUD) among youth, and to investigate recent findings concerning the relationship between cannabis use and mental health concerns, with a focus on how use during adolescence may interact with related mental health disorders.

RECENT FINDINGS

Current data indicate that cannabis use among adolescents has shown both marginal increases and decreases, depending on global location; however, the profile of cannabinoids in cannabis may now be biased toward those that promote psychotogenic and memory-impairing effects. CUD has been found most prevalent among youth. After controlling for multiple confounders, longitudinal research suggests that cannabis use predicts the development of anxiety disorders, depression, suicidal ideation, certain personality disorders, and interpersonal violence. Further, associations have been found stronger in adolescents relative to adults, and younger age of initiation increases the risk of developing mental health disorders.

SUMMARY

Cannabis use among youth remains prevalent, and recent studies are consolidating previous findings that adolescents are especially vulnerable to mental health disorders associated with cannabis. This suggests that cannabis involvement requires increased prominence in research, prevention initiatives, routine screening, and interventions to improve adolescent mental health.

Sex differences in the cumulative incidence of substance use by birth cohort

BACKGROUND

Men present higher overall rates of substance use and abuse than women; yet, evidence suggests that an increase of substance use by the younger cohorts of women in recent decades is narrowing this gap in western societies. Moreover, younger cohorts may also be reporting earlier initiation of substance use, representing an increased risk for developing substance-related problems. With this study we intend to identify changes in the patterns of substance use of men and women in Spain for public health policy, planning and intervention.

METHODS

Sex differences in the cumulative incidence of alcohol, tobacco, cannabis and cocaine were examined by birth cohort using a combined sample of individuals aged 15-64 years from eight editions of the Spanish National Survey on Drugs (1995-2009).

RESULTS

Initiation of substance use in Spain is progressively taking place at younger ages, particularly among women. The gender-gap of life-time occurrence of substance use is narrowing (cannabis and cocaine) almost closing (alcohol) and even reversing (tobacco) in the youngest cohort.

CONCLUSION

These results reflect the particular evolution and trends of Spanish society regarding substance use. Women's increased use of substances and the earlier age of initiation of substance use by both sexes present particular challenges for prevention and treatment of future substance-related problems. The trends registered for legal and illegal substances would require re-evaluation of existing prevention policies.

Age-related patterns of drug use initiation among polydrug using regular psychostimulant users

INTRODUCTION AND AIMS

To determine age-related patterns of drug use initiation, drug sequencing and treatment entry among regular psychostimulant users.

DESIGN AND METHODS

Cross-sectional study of 269 regular psychostimulant users, administered a structured interview examining onset of use for major licit and illicit drugs.

RESULTS

The mean age at first intoxication was not associated with age or gender. In contrast, younger age was associated with earlier ages of onset for all of the illicit drug classes. Each additional year of age was associated with a 4 month increase in onset age for methamphetamine, and 3 months for heroin. By the age of 17, those born prior to 1961 had, on average, used only tobacco and alcohol, whereas those born between 1986 and 1990 had used nine different drug classes. The period between initial use and the transition to regular use, however, was stable. Age was also negatively correlated with both age at initial injection and regular injecting. Onset sequences, however, remained stable. Consistent with the age-related patterns of drug use, each additional year of age associated with a 0.47 year increase in the age at first treatment.

DISCUSSION AND CONCLUSIONS

While the age at first intoxication appeared stable, the trajectory through illicit drug use was substantially truncated. The data indicate that, at least among those who progress to regular illicit drug use, younger users are likely to be exposed to far broader polydrug use in their teens than has previously been the case.