Cross-national comparisons of sex differences in opportunities to use

alcohol or drugs, and the transitions to use

J Elisabeth Wells1, Hui Cheng2, Louisa Degenhardt2, 3 Jim Anthony2 plus other

authors from contributing countries

1. Department of Public Health and General Practice University of Otago, Christchurch P O Box 4345 Christchurch Mail Centre Christchurch 8140 NEW ZEALAND Ph: +64-3-364-3616 Fax: +64-3-364-3614 2. Department of Epidemiology Michigan State University B601 West Fee Hall East Lansing MI 48824 UNITED STATES 3. National Drug and Alcohol Research Centre University of New South Wales Sydney NSW 2052 AUSTRALIA

5045 words all up except for this sentence

1

Abstract

Background: Previous studies in the US and among Latin American adolescents have

shown that while males were more likely to have had an opportunity to use drugs, males and

females were equally likely to have progressed from opportunity through to use.

Aim: To see if previous findings are replicated in 14 countries.

Methods: 15 community surveys. Only respondents aged 18-29 at interview were included

in these analyses. Respondents were asked if they had ever had an opportunity to use alcohol

or to use drugs and about use. Transition probabilities of progression from opportunity

through to use were calculated for alcohol and for drugs.

Results: A complex picture emerged with different results for alcohol and for drugs, and for

opportunity to use and for the transition to use. For high income countries alcohol was

widely available and sex differences were small. Males were much more likely than females to

have had an opportunity to use alcohol in Lebanon (85% vs 55%) and in Nigeria (72% vs

51%) but sex differences in transition probabilities were much smaller. For opportunity to

use drugs the largest sex differences were found in Mexico (69% vs 27%) and Colombia

(57% vs 29%), followed by Nigeria (28% vs 17%). Sex differences in transition to use varied

across countries.

Conclusions: In countries where alcohol or drugs are readily available, males and females

may differ little in the first stages of use. Elsewhere women may be protected from use by

lack of opportunity.

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2

Introduction

Gender differences in the use of alcohol and drugs occur in most countries, with males being

more likely than females to use at all ((World Health Organization 1999; Holmila and

Raitasalo 2005)(Louisa – good international review for drugs?). What is less clear is whether

sex differences in the percentage who have ever used drugs have arisen through unequal

opportunity to use alcohol or drugs, or in the progression from opportunity to first use.

There are now a number of US studies which have looked at these two stages, using the

perspective of infectious disease epidemiology in which exposure corresponds to

opportunity to use and consequent infection corresponds to use given opportunity. One of

the earliest such papers looked at marijuana use in the US in National Household Surveys on

Drug Abuse (NHSDA) samples (Van Etten et al. 1997). Subsequent analyses investigated sex

differences for marijuana, cocaine, hallucinogens and heroin and showed that males were

more likely than females to ever have an opportunity to use drugs but that there were few

sex differences in use given opportunity (Van Etten and Anthony 1999; Van Etten et al.

1999), even among subgroups (Van Etten and Anthony 2001).

Similar studies outside the US mainland have been restricted to adolescents at school in

Guam(Storr et al. 2004), Panama (Delva et al. 1999) , Mexico (Wagner et al. 2003; Benjet et

al. 2007), and other Latin American countries (Chen et al. 2004). Again, males were more

likely than females to have an opportunity to use drugs. Use was not assessed in Guam. In

the Latin American countries females were equally or more likely than males to make the

transition from opportunity to first use.

The World Mental Health (WMH) Initiative surveys

(http://www.hcp.med.harvard.edu/wmh/) have included questions for alcohol and drugs

which enable estimates of opportunity to use and the transition from opportunity to first

use. This paper presents results from the first 15 completed surveys in five of the World

Health Organization regions. The first aim is to see if the previous findings from the US and

from Latin American adolescents hold in all these WMH surveys. The second aim is to look

at country-wide measures of gender equality to see if these are associated with the observed

3

gender differences in opportunity to use alcohol or drugs and the transition to first use. If

the rank order of gender differences across countries is similar for alcohol and for drugs, a

single country descriptor such as the Gender Empowerment Measure (GEM)

(http://hdr.undp.org/hdr2006/statistics/indicators/) may explain much of the cross

country variation; if the pattern of differences is not similar for alcohol and drugs, then drug

specific explanations are required.

Because of the complexity of looking at both opportunity to use and use given opportunity,

for alcohol and for drugs, across 15 surveys, in the presence of varying time trends, this

paper presents results only for the youngest age group, namely those who were 18-29 years

of age at the time of interview. This also reduces the recall problems and biases which may

have occurred for older people. Results for other age groups are available online (See

Appendix A).

4

Method

Descriptions of methods for each survey are in the individual country chapters and in the

methods chapters of the first volume from the World Mental Health Survey Consortium (in

press) and in some individual papers (http://www.hcp.med.harvard.edu/wmh/).

Surveys and participants

Data from 15 surveys in 14 countries were included in this study. All surveys produced

probability samples which were representative of the country or regions included. Nine

samples were nationally representative. Table 1 shows the characteristics of the surveys and

the sample sizes.

Table 1: Surveys included

The interview

All surveys used the WMH Composite International Diagnostic Interview (CIDI), which is

now the CIDI 3.0. This is a personal interview delivered either as a Computer Assisted

Personal Interview (CAPI) or a Pencil and Paper Interview (PAPI). The interview was

divided into Part 1, which everyone was asked, and Part 2 which contained additional

sections. Selection into Part 2 was based on responses to Part 1; those with anxiety or mood

diagnoses from Part 1 or reports of a suicide plan or attempt or hospital admission for

mental problems went on to Part 2, as did a random sample of other respondents. The

substance use section was in Part 1 in Mexico, Colombia and New Zealand and in Part 2 in

the other surveys which accounts for much of the variation seen in Table 1 between the total

sample size and the samples used in these analyses.

5

Variables

At the end of the substance use section everyone was asked directly about opportunity ever

to use alcohol or other drugs:

“By an opportunity to use I mean someone offered you alcohol or drugs, or you

were present when others were using and you could have used if you wanted to.

Please do not include times when a health care provider may have offered you

free samples.”

Separate responses were recorded for alcohol and for drugs

Alcohol use and symptom questions were asked prior to questions about other drugs. Drug

use questions (ever, 1st use, use in last year) were asked for four drug groups: cannabis,

cocaine, prescription drugs (used not as prescribed) and a composite group of any other

drugs. Symptom questions were asked only of those who had ever used drugs. The

opportunity to use question, which followed these drug questions, did not distinguish

between drug groups.

Use given opportunity was calculated from reports of use and opportunity for alcohol and

for drugs.

Country measures of gender equality

One measure of gender equality was obtained from the Human Development Report 2006

(http://hdr.undp.org/hdr2006/) which is based on data from 2000 to 2004, covering the

period of the WMH surveys in this paper. The Gender Empowerment Measure (GEM) is a

composite index measuring gender inequality in economic participation and decision making,

political participation and decision-making and power over economic resources

(http://hdr.undp.org/hdr2006/statistics/indicators/). GEM is not available for all countries

(France, Lebanon, Nigeria and China among WMH countries) whereas there is complete

data on the percent of seats held by women in the national parliament (Indicator 12 of the

UN Millenium goals (http://unstats.un.org/unsd/demographic/default.htm).

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Data analysis

All estimates were weighted according to study design variables including the probability of

selection into part 2, if the substance use section was in Part 2. There was also adjustment

for non-response and post-stratification to census variables, where possible. This weighting

was to ensure that each survey would produce results as unbiased as possible for the

population surveyed.

The prevalence of opportunity to use alcohol or drugs, and prevalence of use given the

opportunity to use, for each sex, was estimated by the SURVEYFREQ procedure using SAS

9.1.3. Sex differences in opportunity to use, and use given opportunity to use, were also

estimated using the SURVERYREG procedure.

7

Results

Opportunity to use alcohol or drugs

For males the percentage who had had an opportunity to use alcohol ranged from 72% in

Nigeria up to 100% in Japan, and was over 95% in another seven surveys. For women the

percentage ranged from 51% in Nigeria to 99% in the Netherlands (Table 2), again with

seven other surveys with percentages of 95% or more. Figure 1a illustrates the magnitude of

the observed sex differences in opportunity to use alcohol and the precision of the estimates.

It shows clearly that the largest sex differences were seen in Lebanon (30%) and in Nigeria

(21%). Males were also significantly more likely than females to have had an opportunity to

use alcohol in Mexico (5% difference). The remaining 11 surveys had no significant

difference between men and women, although the precision of the estimated difference

varied widely because of the sample sizes in each country. No survey found men significantly

less likely than women to have had an opportunity to use alcohol

Table 2 about here

Figure 1 about here

A different pattern emerged for opportunity to use drugs. Opportunity to use drugs was

much less common than opportunity to use alcohol for males and for females in all 15

surveys and was under 30% for Lebanon, Nigeria, Japan and both Chinese sites (Table 2).

Figure 1c shows that the largest sex differences were found in Mexico (42%) and Columbia

(28%). The sex differences in Nigeria (11%), the US (9%) and New Zealand (6%) were also

significant. The 10 other surveys did not find significant differences between men and

women in opportunity to use drugs although difference estimates were quite imprecise,

8

especially for low opportunity countries. As for alcohol, there were no surveys in which men

were significantly less likely than women to have had an opportunity to use drugs.

Use given an opportunity to use

For alcohol, the progression from opportunity to actual use was over 90% for males in all

surveys except for Beijing (87%) and Lebanon (75%). For females the range was 80%

(Shanghai) to 99% (Germany and Japan). Figure 2b shows that the sex difference was

significant only in Mexico (8%) and Italy (9%) with a small but marginally significant

difference in Colombia (1%). Germany and New Zealand had quite precise small estimates

(1% and 0% respectively). Other surveys had broader confidence intervals for the sex

difference, particularly low use countries such as Lebanon, Nigeria, Beijing and Shanghai.

The evidence for sex differences in the progression to use of alcohol is mixed. Males are

more likely to progress in Mexico and Italy, there is clearly no sex difference in Germany or

New Zealand and only a small difference in Columbia but in all the other surveys the

estimates of sex differences are imprecise.

For drugs the progression from opportunity to use was mostly lower than for alcohol and

ranged widely across countries. Because opportunity to use drugs was less common than

opportunity to use alcohol, the progression estimates from opportunity through to use are

particularly imprecise for those countries where drug use opportunities were low. Much the

largest sex difference was seen in Japan (48%). The three surveys in the Americas also all

showed that males were significantly more likely than females to progress to use: Mexico

(15%), US (15%) and Colombia (12%). In contrast New Zealand (-2%) and Italy (0.1%)

showed quite precisely that there was no sex difference in progression in these countries. No

country other than Germany (-17%) found that males were significantly less likely than

females to progress.

Comparison across cohorts for the US and New Zealand

As previous studies of opportunity to use and the progression to use in adults have all been

carried out in the US, results over all ages and across birth cohorts are reported for that

country to enable comparisons with previous findings. In addition New Zealand results are

reported here because they are based on much the largest sample. Results for all other

9

surveys are presented in Appendix A. Sex differences for alcohol in the US were consistent

in magnitude across the three age cohorts of 18-29 years, 30-44 years and 45+. The sex

difference in opportunity to use drugs was largest in the 45+ age group (23%, p<0.001) but

still significant in the 30-45 age group (6%, p<0.02) and the 18-29 age group (9%,

p<0.0001). The opposite pattern was observed for use of drugs, given opportunity to use.

Sex differences were small in the oldest age group (4%, p=0.33), larger for 30-44 year olds

(9%, p=0.006) and largest for the youngest age group (15%, p<0.0001).

In New Zealand, as in the US, sex differences for alcohol were consistent across age groups

and were small (0% to 2%). In contrast, sex differences decreased across the age groups

from oldest to youngest both for opportunity to use drugs (14%, 9%, 6%) and for use given

opportunity (12%, 6%, -2%).

Discussion

The diversity of results across countries and across drugs (alcohol or other drugs) shows that

there is no consistent pattern of sex differences in opportunity to use or in the progression

from opportunity through to use. This precludes the use of any single measure of gender

equality per country to explain the extent of sex differences across all the countries included

here.

Opportunity to use alcohol was almost universal in the high income countries of Europe,

the US and New Zealand and there were no sex differences. Opportunity to use drugs was

also common in these countries (>70% for all). None of the smaller European surveys

showed clear evidence of sex differences in opportunity to use drugs but in the larger

surveys in the US and New Zealand males were more likely than females to have had an

opportunity to use drugs, although the differences were not large (9% in the US, 6% in New

Zealand). These countries have high values on the Gender Employment Measure (GEM): all

about 0.75 except for Spain (0.65). There is no measure for France.

Mexico and Colombia and Lebanon and Nigeria formed contrasting pairs of countries in

terms of opportunity to use alcohol and drugs. Males were much more likely than females to

10

have an opportunity to use alcohol in Lebanon (30%) and Nigeria (21%) whereas sex

differences were small in Mexico (5%) and Colombia (2%). For opportunity to use drugs

large sex differences were found in Mexico (42%) and Colombia (28%) but differences were

much smaller in Lebanon (6%) and Nigeria (11%). where both sexes had low opportunity to

use drugs. Religious prohibitions against alcohol use may underlie the large sex differences

in opportunity to use alcohol found in the two countries with majority Muslim populations

(Lebanon and Nigeria) whereas alcohol availability is widespread in the two Catholic

countries (Mexico and Colombia). Mexico and Colombia score only moderately on the

GEM (0.60 and 0.51 respectively). There are no GEM scores for Lebanon and Nigeria but

one measure of sexual inequality is that they have the lowest percentage of seats in the

national parliament held by women (2.3%, 6.7%) compared with all the other countries

considered here. Perhaps sex differences in opportunity to use a substance do not appear if

the substance is acceptable in the society but are marked if there are religious or social

sanctions against use.

Japan and the Chinese surveys were distinguished by moderate to high opportunity to use

alcohol but low opportunity to use drugs, with no significant sex differences for either

substance. The opportunity to use drugs in China was so low that there was little room for

sex differences. In Japan females were non-significantly less likely to have an opportunity to

use drugs than males (8% difference).

Sex differences in the progression from opportunity through to use did not follow the same

pattern as was seen for opportunity to use. Only in Mexico were males more likely to go on

to use alcohol although there was considerable uncertainty about such sex differences in

some countries. Sex differences in the progression to use of drugs was large in Japan and

moderate but clear in all three countries in the Americas (US, Mexico, Colombia) even

though they looked very difference in terms of opportunity to use drugs. In some countries

there are sex differences in progression for some substances whereas in other countries or

for other substances sex differences in progression are clearly do not exist (see New

Zealand) or were not large enough to be detected with certainty in these surveys.

11

One limitation of these surveys is that they, like all other epidemiological studies of

substance use, rely on self-report. However by restricting analyses to those aged 18-29 recall

problems will have been less than if all adult ages had been used. Another limitation comes

from non-response, particularly in the European countries apart from Spain and Italy. Even

with response rates of over 70%, which are regarded as acceptable for community surveys,

there is the possibility of non-response bias (WMH book chapter). Furthermore, the

opportunity to use drugs was reported for all drugs together. Thus the across-country

difference in opportunities and progression to use across different types of drugs cannot be

estimated, especially the difference between prescription drugs and illegal drugs. Although

cannabis is usually the first drug to be used in US and New Zealand??? (Degenhardt cross-

national lifetime and onset paper, NZ onset paper if accepted in time to be referenced), it

does not necessarily hold for other countries, especially countries with distinct cultures and

policies (Gureje et al. 2007)

These results from 14 countries for 18-29 year olds do not support the pattern found

previously in the US of greater opportunity to use drugs for males but no difference in the

transition from opportunity to use. There appears to have been a secular change in the US

whereby sex differences in opportunity to use have decreased in recent cohorts while sex

differences in the transition from opportunity through to use have increased. Meanwhile in

New Zealand sex differences have decreased for opportunity and for the transition to use.

..

Conclusions: In countries where alcohol or drugs are readily available, there may be only

small or non-existent sex differences in the first two stages of use, namely an opportunity to

use and then first use. Subsequent consumption differences must occur after first use. In

some other countries women are protected from use by not having the opportunity to do so.

In the two metropolitan cities in China at least, both sexes are protected from drug use

because of its unavailability. These different patterns preclude generalization about sex

differences and require data about each substance in each country.

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Acknowledgements

The surveys discussed in this article were carried out in conjunction with the World Health

Organization World Mental Health (WMH) Survey Initiative. We thank the WMH staff for

assistance with instrumentation, fieldwork, and data analysis. These activities were supported by the

United States National Institute of Mental Health (R01MH070884), the John D. and Catherine T.

MacArthur Foundation, the Pfizer Foundation, the US Public Health Service (R13-MH066849, R01-

MH069864, and R01 DA016558), the Fogarty International Center (FIRCA R01-TW006481), the

Pan American Health Organization, Eli Lilly and Company, Ortho-McNeil Pharmaceutical, Inc.,

GlaxoSmithKline, and Bristol-Myers Squibb. A complete list of WMH publications can be found at

http://www.hcp.med.harvard.edu/wmh/. The Chinese World Mental Health Survey Initiative is

supported by the Pfizer Foundation. The Colombian National Study of Mental Health (NSMH) is

supported by the Ministry of Social Protection, with supplemental support from the Saldarriaga

Concha Foundation. The ESEMeD project is funded by the European Commission (Contracts

QLG5-1999-01042; SANCO 2004123), the Piedmont Region (Italy), Fondo de Investigación

Sanitaria, Instituto de Salud Carlos III, Spain (FIS 00/0028), Ministerio de Ciencia y Tecnología,

Spain (SAF 2000-158-CE), Departament de Salut, Generalitat de Catalunya, Spain, and other local

agencies and by an unrestricted educational grant from GlaxoSmithKline. The World Mental Health

Japan (WMHJ) Survey is supported by the Grant for Research on Psychiatric and Neurological

Diseases and Mental Health (H13-SHOGAI-023, H14-TOKUBETSU-026, H16-KOKORO-013)

from the Japan Ministry of Health, Labour and Welfare. The Lebanese National Mental Health

Survey (LEBANON) is supported by the Lebanese Ministry of Public Health, the WHO (Lebanon),

anonymous private donations to IDRAAC, Lebanon, and unrestricted grants from Janssen Cilag, Eli

Lilly, GlaxoSmithKline, Roche, and Novartis. The Mexican National Comorbidity Survey (MNCS) is

supported by The National Institute of Psychiatry Ramon de la Fuente (INPRFMDIES 4280) and by

13

the National Council on Science and Technology (CONACyT-G30544- H), with supplemental

support from the PanAmerican Health Organization (PAHO). Te Rau Hinengaro: The New Zealand

Mental Health Survey (NZMHS) is supported by the New Zealand Ministry of Health, Alcohol

Advisory Council, and the Health Research Council. The Nigerian Survey of Mental Health and

Wellbeing (NSMHW) is supported by the WHO (Geneva), the WHO (Nigeria), and the Federal

Ministry of Health, Abuja, Nigeria. The South Africa Stress and Health Study (SASH) is supported

by the US National Institute of Mental Health (R01-MH059575) and National Institute of Drug

Abuse with supplemental funding from the South African Department of Health and the University

of Michigan. The Ukraine Comorbid Mental Disorders during Periods of Social Disruption

(CMDPSD) study is funded by the US National Institute of Mental Health (RO1-MH61905). The

US National Comorbidity Survey Replication (NCS-R) is supported by the National Institute of

Mental Health (NIMH; U01-MH60220) with supplemental support from the National Institute of

Drug Abuse (NIDA), the Substance Abuse and Mental Health Services Administration (SAMHSA),

the Robert Wood Johnson Foundation (RWJF; Grant 044780), and the John W. Alden Trust.

Appendix A. Supplementary data – results for older age groups

Supplementary data associated with this article can be found by accessing the online version

of this paper at http://dx.doi.org by entering XXXXXX.

14

References

Benjet, C., Borges, G., Medina-Mora, M. E., Blanco, J., Zambrano, J., Orozco, R., Fleiz, C. Rojas, E., 2007. Drug use opportunities and the transition to drug use among adolescents from the Mexico City Metropolitan Area. Drug Alcohol Depend. 90, 128-134.

Chen, C. Y., Dormitzer, C. M., Bejarano, J. Anthony, J. C., 2004. Religiosity and the earliest stages of adolescent drug involvement in seven countries of Latin America. Am. J. Epidemiol. 159, 1180-1188.

Delva, J., Van Etten, M. L., Gonzalez, G. B., Cedeno, M. A., Penna, M., Caris, L. H. Anthony, J. C., 1999. First opportunities to try drugs and the transition to first drug use: evidence from a national school survey in Panama. Substance Use & Misuse 34, 1451-1467.

Gureje, O., Degenhardt, L., Olley, B., Uwakwe, R., Udofia, O., Wakil, A., Adeyemi, O., Bohnert, K. M. Anthony, J. C., 2007. A descriptive epidemiology of substance use and substance use disorders in Nigeria during the early 21st century. Drug Alcohol Depend. 91, 1-9.

Holmila, M. Raitasalo, K., 2005. Gender differences in drinking: why do they still exist? Addiction 100, 1763-1769.

Storr, C. L., Arria, A. M., Workman, Z. R. Anthony, J. C., 2004. Neighborhood environment and opportunity to try methamphetamine ("ice") and marijuana: evidence from Guam in the Western Pacific region of Micronesia. Substance Use & Misuse 39, 253-276.

Van Etten, M. L. Anthony, J. C., 1999. Comparative epidemiology of initial drug opportunities and transitions to first use: marijuana, cocaine, hallucinogens and heroin. Drug Alcohol Depend. 54, 117-125.

Van Etten, M. L. Anthony, J. C., 2001. Male-female differences in transitions from first drug opportunity to first use: searching for subgroup variation by age, race, region, and urban status. Journal of Womens Health & Gender-Based Medicine 10, 797-804.

Van Etten, M. L., Neumark, Y. D. Anthony, J. C., 1997. Initial opportunity to use marijuana and the transition to first use: United States, 1979-1994. Drug Alcohol Depend. 49, 1-7.

Van Etten, M. L., Neumark, Y. D. Anthony, J. C., 1999. Male-female differences in the earliest stages of drug involvement. Addiction 94, 1413-1419.

Wagner, F. A., Gonzalez-Forteza, C., Aguilera R.M. Ramos-Lira, L. E., Medina-Mora, M. E. Anthony, J. C., 2003. Oportunidades de exposicion aluso de drogas entre estudiantes de secundaria dila cuidad de Mexico. Salud Mental 26, 1402-1412.

World Health Organization, 1999. Drinking prevalence. Global Status Report on Alcohol (document WHO/HSC/SAB/99.11). World Health Organization. Geneva, World Health Organization,.

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Table 1: Surveys and samples

Sample size Survey1

Name Year Response

rate2

Total Ages 18-29 asked about ‘opportunity to use’

Sample Characteristics3

The Americas

Mexico M-NCS 2001-2 76.6% 5782 2055 Stratified multistage clustered area probability sample of household residents in all urban areas of the country (approximately 75% of the total national population)

United States NCS-R 2002-3 70.9% 9281 1377 Stratified multistage clustered area probability sample of household residents, nationally representative

Colombia NSMH 2003 94.3% 4426 1431 Stratified multistage clustered area probability sample of household residents in all urban areas of the country (approximately 73% of the total national population)

Europe

Belgium ESEMeD 2001-2 50.6% 2419 139 Stratified multistage clustered probability sample of individuals residing in households from the national register of Belgium residents, nationally representative

Netherlands ESEMeD 2002-3 56.4% 2372 135 Stratified multistage clustered probability sample of individuals residing in households that are listed in municipal postal registries, nationally representative

Germany ESEMeD 2002-3 57.8% 3555 191 Stratified multistage clustered probability sample of individuals from community resident registries, nationally representative

Spain ESEMeD 2001-2 78.6% 5473 340 Stratified multistage clustered area probability sample of household residents, nationally representative

France ESEMeD 2001-2 45.9% 2894 237 Stratified multistage clustered sample of working telephone numbers merged with a reverse directory (for listed numbers). Initial recruitment was by telephone, with supplemental in-person recruitment in households with listed numbers, nationally representative

Italy ESEMeD 2001-2 71.3% 4712 330 Stratified multistage clustered probability sample of individuals from municipality resident registries, nationally representative

The Eastern Mediterranean

Lebanon LNMHS 2002-3 70.0% 2857 235 Stratified multistage clustered area probability sample of household residents, nationally representative

17

18

Africa

Nigeria NSMHW 2002-4 79.9% 6752 697 Stratified multistage clustered area probability sample of household residents in the Yoruba-speaking Southwestern and North Central parts of the country (approximately 22% of the total national population)

Western Pacific

Japan WMHJ 2002-4 56.4% ? 2436 94 Unclustered 2-stage probability sample of individuals residing in households in 4 metropolitan areas (Fukiage, Kushikino, Nagasaki, Oyayama)

Beijing B-WMH 2002-3 74.8% 2633 115 Stratified multistage clustered area probability sample of household residents in the Beijing metropolitan area

Shanghai S-WMH 2002-3 74.6% 2568 147 Stratified multistage clustered area probability sample of household residents in the Shanghai metropolitan area

New Zealand NZMHS 2003-4 73.3% 12,992 2350 Stratified multistage clustered area probability sample of household residents, nationally representative

1ESEMeD (The European Study Of The Epidemiology Of Mental Disorders); NSMH (The Colombian National Study of Mental Health); NHS (Israel National Health Survey); WMHJ2002-2003 (World Mental Health Japan Survey); LEBANON (Lebanese Evaluation of the Burden of Ailments and Needs of the Nation); M-NCS (The Mexico National Comorbidity Survey); NZMHS (New Zealand Mental Health Survey); NSMHW (The Nigerian Survey of Mental Health and Wellbeing); B-WMH (The Beijing World Mental Health survey); S-WMH (The Shanghai World Mental Health Survey); SASH (South Africa Health Survey); CMDPSD (Comorbid Mental Disorders during Periods of Social Disruption); NCS-R (The US National Comorbidity Survey Replication). 2The response rate is calculated as the ratio of the number of households in which an interview was completed to the number of households originally sampled, excluding from the denominator households known not to be eligible either because of being vacant at the time of initial contact or because the residents were unable to speak the designated languages of the survey. 3Most WMH surveys are based on stratified multistage clustered area probability household samples in which samples of areas equivalent to counties or municipalities in the US were selected in the first stage followed by one or more subsequent stages of geographic sampling (e.g., towns within counties, blocks within towns, households within blocks) to arrive at a sample of households, in each of which a listing of household members was created and one or two people were selected from this listing to be interviewed. No substitution was allowed when the originally sampled household resident could not be interviewed. These household samples were selected from Census area data in all countries other than France (where telephone directories were used to select households) and the Netherlands (where postal registries were used to select households). Several WMH surveys (Belgium, Germany, Italy) used municipal resident registries to select respondents without listing households. The Japanese sample is the only totally un-clustered sample, with households randomly selected in each of the four sample areas and one random respondent selected in each sample household. Nine of the 15 surveys are based on nationally representative household samples, while two others are based on nationally representative household samples in urbanized areas (Colombia, Mexico).

Table 2: Opportunities to use, and subsequent use, of alcohol and other drugs, in males and

females aged 18-29 years

Opportunity to use Use, given the opportunity to use Males Females Males Females Alcohol Alcohol Mexico 0.98 0.93 0.93 0.85 United States 0.99 0.98 0.96 0.93 Colombia 0.99 0.97 0.98 0.97 Belgium 0.85 0.95 1.00 0.98 Netherlands 0.94 0.99 0.99 0.90 Germany 0.99 0.98 1.00 0.99 Spain 0.97 0.95 0.96 0.95 France 0.96 0.94 1.00 0.97 Italy 0.86 0.80 0.98 0.89 Lebanon 0.85 0.55 0.75 0.63 Nigeria 0.72 0.51 0.92 0.90 Japan 1.00 0.98 0.95 0.99 Beijing 0.83 0.90 0.87 0.84 Shanghai 0.84 0.79 0.95 0.80 New Zealand 0.99 0.97 0.96 0.96 Other drugs1 Other drugs1 Mexico 0.69 0.27 0.33 0.18 United States 0.93 0.84 0.69 0.54 Colombia 0.57 0.29 0.41 0.29 Belgium 0.72 0.66 0.71 0.91 Netherlands 0.75 0.80 0.51 0.62 Germany 0.89 0.89 0.75 0.92 Spain 0.82 0.91 0.80 0.83 France 0.86 0.80 0.87 0.90 Italy 0.72 0.74 0.94 0.93 Lebanon 0.16 0.10 0.59 0.54 Nigeria 0.28 0.17 0.83 0.87 Japan 0.21 0.13 1.00 0.52 Beijing 0.05 0.02 0.84 1.00 Shanghai 0.01 0.07 0.73 1.00 New Zealand 0.87 0.81 0.71 0.73 1 Cannabis, cocaine, prescription drugs (used not as prescribed or without a prescription), any other drugs

.

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Figure Legend.

Figure 1. Sex differences (M-F) in opportunity to use alcohol or drugs and in subsequent use, given

the opportunity to use, 18-29 years.

a) Opportunity to use alcohol b) Use of alcohol, given opportunity to use

c) Opportunity to use drugs d) Use of drugs, given opportunity to use

21