Psychosocial Concerns and Health-Compromising Behaviors among Overweight and Nonoverweight Adolescents

Objective: To compare weight-specific and global psychosocial concerns and health-compromising behaviors among overweight and nonoverweight youth across gender and ethnicity. Methods: A cross-sectional school-based survey of 31,122 adolescents in grades 7 to 12. Based on self-reported heights and weights, respondents were categorized as nonoverweight (body mass index (BMI) <85th percentile), moderately overweight (85th percenile <BMI <95th percentile), or severely overweight (BMI >95th percentile). Results: Global psychosocial concerns, such as emotional well-being, suicidal ideation, future job concerns, and peer concerns, did not differ greatly between nonoverweight, moderately overweight, and severely overweight adolescents. Substance abuse behaviors were equally or less prevalent among the overweight group. Overweight girls were significantly less likely to consume alcohol, whereas overweight boys were at lower risk for marijuana use. In contrast, overweight youth were more likely to perceive their health as only fair or poor and were more likely to express weight-specific concerns and engage in behaviors such as chronic dieting and binge eating than nonoverweight youth. Overweight American Indian girls perceived their physical health more positively than nonoverweight American Indian girls. Strong associations were found between overweight status and chronic dieting among African American boys and girls. Conclusions: Nutritional counseling and educational programs need to address the weight-specific concerns and behaviors of overweight adolescents. However, assumptions regarding global psychosocial concerns and health-compromising behaviors among overweight adolescents of different genders and ethnicities should be avoided. These broad issues need to be explored in more depth at both the research and intervention levels.     

Tobacco, alcohol and illicit drug use among Aboriginal youth living off-reserve: results from the Youth Smoking Survey

Background

Despite the high prevalence of smoking among Aboriginal youth, there is a paucity of research related to tobacco use and other risk behaviours among Aboriginal youth living off-reserve in Canada. We used data from the national Youth Smoking Survey to characterize non-traditional tobacco use, exposure to second-hand smoke, and alcohol and drug use among Aboriginal youth living off-reserve. We examined whether these youth were at increased health risk compared with non-Aboriginal youth.

Methods

We examined cigarette smoking behaviour, use of other tobacco products, use of alcohol and other drugs, and exposure to second-hand smoke among 2620 Aboriginal youth living off-reserve and 26 223 non-Aboriginal youth in grades 9 to 12 who participated in the 2008/09 Youth Smoking Survey.

Results

The prevalence of current smoking among the Aboriginal youth was more than double that among non-Aboriginal youth (24.9% v. 10.4%). Aboriginal youth also had a higher prevalence of regular exposure to second-hand smoke at home (37.3% v. 19.7%) and in cars (51.0% v. 30.3%). Aboriginal youth were more likely than non-Aboriginal youth to be current smokers, to be regularly exposed to second-hand smoke, to have tried marijuana and other illicit drugs, and to engage in binge drinking. They were less likely than non-Aboriginal youth to have tried to quit smoking.

Interpretation

Current national estimates of smoking, and alcohol and illicit drug use among youth underestimate the prevalence of these behaviours among Aboriginal youth living off-reserve. Our findings highlight the need for culturally appropriate prevention and cessation policies and programs for this at-risk population.Compared with the general population in Canada, Aboriginal youth start smoking earlier¹ and have a higher prevalence of smoking,^1–3 with female Aboriginals at greatest risk.¹ Research has also shown that Aboriginal youth have high rates of binge drinking¹ and are more likely than non-Aboriginal youth to use marijuana.⁴Despite the high prevalence of smoking among Aboriginal youth in Canada, there is a paucity of research related to their patterns of tobacco use, especially among Aboriginals living off-reserve.⁵ Most Aboriginals in Canada live off-reserve,⁶ and those 15 years of age and older are more likely than non-Aboriginals to have chronic health conditions, to drink heavily and to smoke.⁷ Given that the Canadian Tobacco Control Strategy emphasizes targeting youth, young adults, First Nations, Inuit and other Aboriginal groups,⁸ a better understanding of tobacco use among Aboriginal youth living off-reserve is required.We conducted this study to examine patterns of tobacco use, exposure to second-hand smoke and the prevalence of alcohol and other drug use among Aboriginal youth living off-reserve. We compared these data with those for non-Aboriginal youth using nationally representative data from the 2008/09 Youth Smoking Survey.     

Early sexual intercourse and risk factors in Croatian adolescents

Sexual behaviour in adolescence is a sensitive issue and has possible immediate and long term medical and psychical consequences. The aim of the study was to examine whether early sexual intercourse varies by gender and how is associated with unhealthy behaviour and factors of psycho-social well-being. 773 boys and 857 girls of 15.5 years old, included in a representative national school-based survey, conducted in Croatia in 2006, were invited to fill in anonymous questionnaires. Sexual experience before the age of 16 years was reported by 28.6% of the boys and 16.5% of the girls. Early sexual experience in boys was associated with smoking, drinking of alcohol, marijuana taking, physical fighting, and bullying other The odds ratio was highest for smoking. (OR:8. 1; CI:5.4-12. 1). For girls the same variables were associated with the early sexual intercourse, marijuana use being the strongest independent predictor (OR:8.0; CI:5.0-12.6). While controlled for other behaviours, daily smoking remained the strongest predictor for both genders. Girls who had early sexual experience were more prone to be dissatisfied with their health (OR:2.9; CI:2.0-4.2), with their life (OR:2.1; CI:1.4-3.0), communication with father and mother (OR:1.9; CI:1.2-2.8 and OR:1. 7; CI:1.1-2.6) and reported more psychosomatic symptoms (OR:2.9; CI:2.0-4.3). For both genders odds were higher if they had good communication with the friend of the opposite gender. Evenings spent out with friends were associated to early sexual experience in boys and girls as well as poorer school achievement. Early menarche was associated with the probability of being engaged in the early sexual intercourse and with smoking, marijuana use and psychosomatic symptoms. Early sexual intercourse is associated with unhealthy behaviour such as smoking, substance abuse, aggressiveness and lower psychosocial well-being. Preventive educational programmes should follow multi-facet approaches and recognize differences between boys and girls. Human papillomavirus (HPV) vaccination could be part of a comprehensive approach and is not to be viewed as an isolated activity.     

Components of School Engagement Among African American Adolescents

Human-animal relationships are ubiquitous and diverse across the life span and may be especially salient among children and adolescents. However, there is little information regarding whether human-animal interaction (HAI) is actually linked to young people's positive development in normative, nontherapeutic settings. Therefore, the purpose of this study was to explore if and how HAI may be linked to positive youth development (PYD) using data from the 4-H Study of PYD. Results suggested that emotions and cognitions about animals were related to indices of positive development. The implications of these findings, and suggestions for new areas of inquiry regarding the role of HAI as an important developmental context, are discussed.     

Effects of the Positive Action Program on Indicators of Positive Youth Development Among Urban Youth

This study evaluated effects of Positive Action, a school-based social-emotional and character development intervention, on indicators of positive youth development (PYD) among a sample of low-income, ethnic minority youth attending 14 urban schools. The study used a matched-pair, cluster-randomized controlled design at the school level. A multiple-measure self-report protocol assessed four key strengths and resources for PYD: self-concept, peer affiliations, ethics, and social skills. Students (n = 1170) were assessed from grades 3 to 8; the duration of the intervention, with drop-outs and late entrants was included in analyses. Growth curve analyses revealed evidence of favorable program effects on each of the four types of resources. The study contributes to PYD research by providing evidence for school-based interventions in low-income, urban contexts for ethnic minority youth.     

Cancer patterns in Canada.

Data from a cross-sectional survey of the health of Ontario children carried out in 1983 were used to provide estimates of the prevalence, patterns and sociodemographic correlates of the use of tobacco, alcohol and illicit drugs (substance use) among adolescents aged 12 to 16 years. Ninety-one percent of selected households participated. The prevalence rates of all categories of substance use, except use of inhalants, increased with increasing age. Among children aged 14 to 16 years the rates for girls were higher than those for boys for all categories of substance use except use of other, nondefined drugs. The prevalence rates of substance use tended to be higher in small urban areas except for use of marijuana (more prevalent in large urban areas) and use of inhalants (more prevalent in rural areas). The strongest evidence of clustering of substance use within families was found for smoking. Children who used less prevalent drugs (e.g., "hard" drugs) also tended to use the more prevalent ones (e.g., marijuana, tobacco and alcohol). Associations between substance use and low socioeconomic status suggested a positive relation with smoking and a negative relation with use of alcohol. The findings highlight the need for preventive programs aimed at specific subgroups in the adolescent population.     

Focus: Preventive Medicine: Assessing the Social Influences,Self-Esteem,and Stress of High School Students Who Vape

Adolescent vaping is rapidly rising in Canada, and e-cigarettes have become the most widely used tobacco product among high school students; 29% of students in grades 10 to 12 reported e-cigarette use in 2019. Vaping among adolescents is a problem because the long-term health consequences of e-cigarettes remain unknown, large numbers of teens are becoming addicted to the harmful drug nicotine, and vaping has been shown to increase risk of initiation of combustible tobacco product use. To address the gaps in the current understanding of adolescent e-cigarette use, this study aims to examine the role of social peer and family influence, self-esteem, and stress on teen vaping. Seventy-nine students in grades 10 to 12 at an independent, co-ed high school in Toronto, Ontario completed an online survey about factors that influence them to vape, and about their perceived self-esteem and stress. Survey data was analyzed using Chi-Square tests and T-tests. Common motivations for vaping included stress relief (70%) and peer influence (60%). Family history of smoking or vaping and the ability to vape indoors also influenced vaping habits. Notably, e-cigarette users reported higher stress levels than non-users, but self-esteem levels were comparable. Our findings suggest that high school vaping prevention strategies should focus on stress reduction and encourage healthy coping strategies. Similar research studies should be conducted in other high schools, and future research should further explore the correlation between stress and adolescent vaping.     

Drinking, substance use and the operation of motor vehicles by young adolescents in Canada

Background

Impaired driving is a recognized cause of major injury. Contemporary data are lacking on exposures to impaired driving behaviours and related injury among young adolescents, as well as inequities in these youth risk behaviours.

Methods and Findings

Cycle 6 (2009/10) of the Health Behaviour in School-Aged Children survey involved 26,078 students enrolled in 436 Canadian schools. We profiled cross-sectionally the reported use of alcohol, marijuana, or other illicit drugs by on-road and off-road vehicle operators when young adolescents (mean age 13.3 (±1.6) years) were either driving or riding as a passenger. Comparisons were made across vulnerable subgroups. Multi-level logistic regression analyses were used to quantify the effects of the driving behaviours on risks for motor vehicle-related injury. Attributable risk fractions were also estimated. A total of 10% (±3%) of participants reported recent operation of an on-road or off-road motor vehicle after consuming alcohol, marijuana, or other illicit drugs, while 21% (±3%) reported riding as a passenger with a driver under the same conditions. Larger proportions of youth reporting these risk behaviours were males, and from older age groups, rural communities, and socio-economically disadvantaged populations. The behaviours were consistently associated with increased risks for motor vehicle-related injury at the individual level (RR 2.35; 95% CI: 1.54 to 3.58 for frequent vs. no exposure as a driver; RR 1.68; 95% CI: 1.20 to 2.36 for frequent vs. no exposure as a passenger) and at the population level (Attributable Risk Fraction: 7.1% for drivers; 14.0% for passengers). The study was limited mainly by its reliance on self-reported data.

Conclusion

Impaired driving is an important health priority among young adolescents in Canada. Inequities in the involvement of younger adolescents in these risk behaviours suggest the need for targeted interventions for specific subgroups such as youth from rural communities, and among socially disadvantaged populations.     

Protobacco Media Exposure and Youth Susceptibility to Smoking Cigarettes,Cigarette Experimentation,and Current Tobacco Use among US Youth

Purpose

Youth are exposed to many types of protobacco influences, including smoking in movies, which has been shown to cause initiation. This study investigates associations between different channels of protobacco media and susceptibility to smoking cigarettes, cigarette experimentation, and current tobacco use among US middle and high school students.

Methods

By using data from the 2012 National Youth Tobacco Survey, structural equation modeling was performed in 2013. The analyses examined exposure to tobacco use in different channels of protobacco media on smoking susceptibility, experimentation, and current tobacco use, accounting for perceived peer tobacco use.

Results

In 2012, 27.9% of respondents were never-smokers who reported being susceptible to trying cigarette smoking. Cigarette experimentation increased from 6.3% in 6th grade to 37.1% in 12th grade. Likewise, current tobacco use increased from 5.2% in 6th grade to 33.2% in 12th grade. Structural equation modeling supported a model in which current tobacco use is associated with exposure to static advertising through perception of peer use, and by exposure to tobacco use depicted on TV and in movies, both directly and through perception of peer use. Exposure to static advertising appears to directly increase smoking susceptibility but indirectly (through increased perceptions of peer use) to increase cigarette experimentation. Models that explicitly incorporate peer use as a mediator can better discern the direct and indirect effects of exposure to static advertising on youth tobacco use initiation.

Conclusions

These findings underscore the importance of reducing youth exposure to smoking in TV, movies, and static advertising.     

All Military Adolescents Are Not the Same: Sexuality and Substance Use among Adolescents in the U.S. Military Healthcare System

Data examining sexuality and substance use among active duty and military-dependent youth is limited; however, these psychosocial factors have military implications. Adolescents and young adults aged 12–23 were recruited from an active-duty trainee clinic (n = 225) and a military pediatric clinic (n = 223). Active duty participants were more likely to be older, male, White, previous tobacco users, and report a history of sexual activity and less contraception use at their most recent intercourse, compared to the dependent group. Over 10% of all participants indicated attraction to members of the same gender or both genders. In logistic regression analysis, non-White participants were less likely to use contraception compared to White participants. Adolescents and young adults seen in military clinics frequently engage in high-risk behavior. Clinicians who care for military youth should assess their patient’s psychosocial history. Further study of this population is warranted to identify factors that may influence risk and resilience.     

Prevalence and Correlates of HIV Infection among Street Boys in Kisumu,Kenya

Introduction

Despite their perceived vulnerability to HIV, East African street youth have been neglected in HIV prevention research. We examined HIV seroprevalence and correlates of HIV infection in a sample of male street youth in Kisumu, Kenya.

Methods

We enrolled a street-recruited sample of 13–21 year old street youth. Participants completed a survey followed by voluntary HIV counseling and testing. Survey items included demographics, homelessness history, survival activities, sexual behavior and substance use. We examined the relationship between predictor variables, markers of coercion and marginalization and HIV.

Results

The sample included 296 males. Survival activities included garbage picking (55%), helping market vendors (55%), begging (17%), and working as porters (46%) or domestic workers (4%). Forty-nine percent of participants reported at least weekly use of alcohol and 32% marijuana. Forty-six percent of participants reported lifetime inhalation of glue and 8% fuel. Seventy-nine percent of participants reported lifetime vaginal sex, 6% reported lifetime insertive anal sex and 8% reported lifetime receptive anal sex. Twelve (4.1%; 95% CI: 2.3–7.0) participants tested positive for HIV. Of those, all had been on the street for at least one year and all had engaged in vaginal sex. Occupations placing youth at particular risk of coercion by adults, including helping market vendors (prevalence ratio (PR) = 8.8; 95% CI: 1.2–67.5) and working as domestic workers (PR = 4.6; 95% CI: 1.1–19.0), were associated with HIV infection. Both insertive anal sex (PR = 10.2; 95% CI: 3.6–29.4) and receptive anal sex (PR = 3.9; 95% CI: 1.1–13.4) were associated with HIV infection. Drug use, begging, and garbage picking were not associated with HIV infection.

Conclusions

Although HIV prevalence in our sample of street youth is comparable to that of similarly-aged male youth in Nyanza Province, our findings highlight behavioral factors associated with HIV infection that offer opportunities for targeted prevention among street youth in East Africa.     

Unemployment and illegal drug use: concordant evidence from a prospective study and national trends.

Data from a previous study of 1036 young people in the Lothian region that indicated an association between unemployment and illegal drug use were examined in more depth to investigate the inter-relation between duration of unemployment and the use of illegal drugs, alcohol, and tobacco. After factors such as social class background and educational qualifications had been taken into account a weak but significant association was found between duration of unemployment and illegal drug use. No such association was found for alcohol or tobacco. Similar results were obtained from an analysis of national statistics related to unemployment and illegal drug use. Both sets of data thus indicate that illegal drug use is moderately associated with unemployment.     

Diet, tobacco, alcohol, and stress as causes of coronary artery heart disease: an ecological trend analysis of national data

The present investigation examined the temporal relationships between changes in coronary artery heart disease (CAHD) mortality rates from whites (1938-1980) and changes in national measures of dietary elements, tobacco consumption, alcohol consumption, and unemployment. The magnitude and latency of the causal relationships were estimated with the use of cross-lagged correlation functions (CCFs) and Granger causality tests. Preliminary CCFs showed consistent correlational patterns between CAHD and tobacco, ethanol, and dietary fats. There was little association between CAHD and dietary cholesterol. Ethanol, tobacco, and the ratio of saturated to polyunsaturated fats (S:P) were analyzed for directional causality using Granger causality tests. The S:P ratio demonstrated a unidirectional Granger causal relationship with CAHD mortality in all sex and age groups. The estimated latency of this relationship was 23 to 30 years. This finding supports a causal relationship between diet, specifically fats, and the risk of CAHD two or three decades later.     

Ethnic Identity and Positive Youth Development in Adolescent Males: A Culturally Integrated Approach

The present study examined the relation between ethnic identity and indicators of positive youth development (PYD) in a sample of low-income, urban Black and Latino male youth (N = 254; 66% Black, mean age = 14). Using structural equation modeling, a two-factor model of PYD and ethnic identity was found to provide the best fit to the data with a significant, positive relation between the two factors. At age 14, PYD was positively related to concurrent involvement in prosocial activities, and negatively related to criminal and externalizing behaviors; ethnic identity was related to lower levels of internalizing symptoms. The PYD factor was also related to higher prosocial activity involvement and lower criminal offending at age 15. The findings suggest that male Black and Latino teens living in urban poverty have intrapersonal competencies that promote healthy outcomes and that integration of culturally-relevant factors can enhance our understanding of positive youth development.     

Nonmedical drug use among adolescent students: highlights from the 1999 Ontario Student Drug Use Survey

BACKGROUND: During the 1990s, rates of nonmedical drug use among adolescents escalated. We assessed data from 5 cycles of the Ontario Student Drug Use Survey for overall trends in the proportion of students reporting illegal drug use between 1991 and 1999. METHODS: The survey is a repeated, cross-sectional, 2-stage cluster-design survey of students enrolled in grades 7, 9, 11 and 13. Outcome measures were prevalence of use of 17 drugs, including alcohol and tobacco, over the 12 months preceding the survey. RESULTS: The rates of drug use increased between 1993 and 1999. The 95% confidence intervals (CIs) for the differences in proportions between 1997 and 1999 indicated significant increases in the overall use of 6 drugs: alcohol (95% CIdiff 6.1, 1.9-10.3), cannabis (95% CIdiff 46.3, 0.2-8.4), glue (95% CIdiff 2.3, 1.3-3.3), other solvents (95% CIdiff 5.0, 3.1-6.3), barbiturates (95% CIdiff 1.9, 0.4-3.4) and hallucinogens such as mescaline and psilocybin (95% CIdiff 3.5, 0.8-6.9). Fewer grade 7 students in 1999 than in earlier cohorts reported using alcohol or cigarettes by age 9. INTERPRETATION: The public health implications of the findings are mixed. On the positive side, there is no evidence of increases in early onset of drug use. On the negative side, the overall proportion of students reporting illegal drug use has continued to rise.     

Correlates of Adolescent Marijuana Use as Related to Age,Sex, and Ethnicity

This study examines the interactive effects of background factors and personality/attitudinal and perceived environmental dimensions on adolescent drug behavior. Data were collected during home interviews using a structured interview schedule. The sample consisted of 403 British West Indian black, American black, and white adolescents, ranging in age from 13 to 17. Results suggested that two processes, nonconformity to conventional middle class values at both the personality/attitudinal and institutional level, and modeling of familial and peer drug use account in large part for adolescent drug behavior. The majority of correlates of adolescent drug behavior were similar in different sex, age, and ethnic groups.     

Sperm count, morphology and fluorescent body frequency in autopsy service workers exposed to formaldehyde

A battery of monitoring tests that could indicate genetic damage was used to investigate occupational formaldehyde exposure in a population of a hospital autopsy service workers. 11 exposed individuals and 11 matched controls were evaluated for sperm count, abnormal sperm morphology and 2F-body frequency. Subjects were matched for sex, age and customary use of alcohol, tobacco and marijuana. Additional information was collected on health, medications and other exposures to toxins. 10 subjects were employed for 4.3 months (range 1-11 months) prior to the first sample and 1 was employed for several years. Formaldehyde exposures were episodic but with a time weighed average between 0.61 and 1.32 ppm (weekly exposure range 3-40 ppm X h). Exposed and control subjects were sampled 3 times at 2-3 month intervals. Sperm morphology was also evaluated in B6C3F1 mice after 5 daily oral doses of 100 mg/kg formalin. No increase in abnormal morphology was detected in the treated animals. In humans, no statistically significant differences were observed between the exposed and control groups for the observed variables. Reduced sperm count correlated with increased abnormal morphology and 2F-body frequency in the exposed group but not in the control group. Evaluation of the impact of incidental exposures suggests a reduced count with marijuana use and increased abnormal morphology with medications used by controls. No effects on sperm were seen from formaldehyde or its metabolites in this population after occupational exposure, nor in mice following a high acute exposure. It is possible that minor effects might have occurred. The lack of an effect in this study may be due to a lack of statistical power to detect effects at this exposure level.     

The relative risks and etiologic fractions of different causes of death and disease attributable to alcohol,tobacco and illicit drug use in Canada

BACKGROUND: In 1996 the number of deaths and admissions to hospital in Canada that could be attributed to the use of alcohol, tobacco and illicit drugs were estimated from 1992 data. In this paper we update these estimates to the year 1995. METHODS: On the basis of pooled estimates of relative risk, etiologic fractions were calculated by age, sex and province for 90 causes of disease or death attributable to alcohol, tobacco or illicit drugs; the etiologic fractions were then applied to national mortality and morbidity data for 1995 to estimate the number of deaths and admissions to hospital attributable to substance abuse. RESULTS: In 1995, 6507 deaths and 82,014 admissions to hospital were attributed to alcohol, 34,728 deaths and 194,072 admissions to hospital were attributed to tobacco, and 805 deaths and 6940 admissions to hospital were due to illicit drugs. INTERPRETATION: The use and misuse of alcohol, tobacco and illicit drugs accounted for 20.0% of deaths, 22.2% of years of potential life lost and 9.4% of admissions to hospital in Canada in 1995.     

A Latent Growth Curve Model of Delinquent Activity Among Adolescents

Latent growth curve (LGM) modeling of a 4-wave longitudinal dataset was conducted to examine a segment of the age-related, quadratic curve for adolescent delinquent activity. A quadratic (inverted U-shaped) LGM model was supported for the sample of 1,016 adolescents and indicated a temporal pattern across the 4 waves of an increase in delinquent activity, a plateau or asymptote, and then an initial deceleration. A time-invariant predictor model was specified to account for variation in intraindividual change in delinquency. Male gender, lower family support, greater peer alcohol use, more stressful life events, and lower grades significantly predicted the intercept; a (less) difficult temperament predicted the linear growth parameter; and lower peer alcohol use, a less difficult temperament, and higher grades predicted the quadratic component that was associated with a deceleration in delinquency. Person-centered analyses for a subgroup of adolescents engaged in persistently high, versatile delinquent activity indicated that these adolescents had temperamentally higher activity levels, lower positive affect, greater inflexibility, more overt and covert conflict with best friends, more childhood conduct problems, and greater current substance use.     

Toward a global view of alcohol, tobacco, cannabis, and cocaine use: findings from the WHO World Mental Health Surveys

Background

Alcohol, tobacco, and illegal drug use cause considerable morbidity and mortality, but good cross-national epidemiological data are limited. This paper describes such data from the first 17 countries participating in the World Health Organization''s (WHO''s) World Mental Health (WMH) Survey Initiative.

Methods and Findings

Household surveys with a combined sample size of 85,052 were carried out in the Americas (Colombia, Mexico, United States), Europe (Belgium, France, Germany, Italy, Netherlands, Spain, Ukraine), Middle East and Africa (Israel, Lebanon, Nigeria, South Africa), Asia (Japan, People''s Republic of China), and Oceania (New Zealand). The WHO Composite International Diagnostic Interview (CIDI) was used to assess the prevalence and correlates of a wide variety of mental and substance disorders. This paper focuses on lifetime use and age of initiation of tobacco, alcohol, cannabis, and cocaine. Alcohol had been used by most in the Americas, Europe, Japan, and New Zealand, with smaller proportions in the Middle East, Africa, and China. Cannabis use in the US and New Zealand (both 42%) was far higher than in any other country. The US was also an outlier in cocaine use (16%). Males were more likely than females to have used drugs; and a sex–cohort interaction was observed, whereby not only were younger cohorts more likely to use all drugs, but the male–female gap was closing in more recent cohorts. The period of risk for drug initiation also appears to be lengthening longer into adulthood among more recent cohorts. Associations with sociodemographic variables were consistent across countries, as were the curves of incidence of lifetime use.

Conclusions

Globally, drug use is not distributed evenly and is not simply related to drug policy, since countries with stringent user-level illegal drug policies did not have lower levels of use than countries with liberal ones. Sex differences were consistently documented, but are decreasing in more recent cohorts, who also have higher levels of illegal drug use and extensions in the period of risk for initiation.