Table 1.

World Mental Health sample characteristics by World Bank Income categories^a

					Sample size
Country	Surveyb	Sample characteristicsc	Field dates	Age range	Part 1	Part 2	Response rated (%)
I. Low –lower-middle-income countries
Colombia	NSMH	All urban areas of the country (approximately 73% of the total national population)	2003	18–65	4426	2381	87.7
Iraq	IMHS	Nationally representative	2006–7	18+	4332	4332	95.2
Nigeria	NSMHW	21 of the 36 states in the country, representing 57% of the national population. The surveys were conducted in Yoruba, Igbo, Hausa and Efik languages	2002–4	18+	6752	2143	79.3
Peru	EMSMP	Five urban areas of the country (approximately 38% of the total national population)	2004–5	18–65	3930	1801	90.2
PRCe Beijing/Shanghai	B-WMH & S-WMH	Beijing and Shanghai metropolitan areas.	2001–3	18+	5201	1628	74.7
PRCe Shen Zhenf	Shenzhen	Shenzhen metropolitan area. Included temporary residents as well as household residents	2005–7	18+	7132	2475	80.0
Ukraine	CMDPSD	Nationally representative	2002	18+	4725	1720	78.3
Total					36 498	16 480
II. Upper-middle-income countries
Brazil- São Paulo	São Paulo Megacity	São Paulo metropolitan area	2005–8	18+	5037	2942	81.3
Bulgaria	NSHS	Nationally representative	2002–6	18+	5318	2233	72.0
Colombia (Medellin)g	MMHHS	Medellin metropolitan area	2011–12	18–65	3261	1673	97.2
Lebanon	LEBANON	Nationally representative	2002–3	18+	2857	1031	70.0
Mexico	M-NCS	All urban areas of the country (approximately 75% of the total national population)	2001–2	18–65	5782	2362	76.6
Romania	RMHS	Nationally representative	2005–6	18+	2357	2357	70.9
South Africaf	SASH	Nationally representative	2002–4	18+	4315	4315	87.1
Total					28 927	16 913
III. High-income countries
Belgium	ESEMeD	Nationally representative	2001–2	18+	2419	1043	50.6
France	ESEMeD	Nationally representative	2001–2	18+	2894	1436	45.9
Germany	ESEMeD	Nationally representative	2002–3	18+	3555	1323	57.8
Israel	NHS	Nationally representative	2003–4	21+	4859	4859	72.6
Italy	ESEMeD	Nationally representative	2001–2	18+	4712	1779	71.3
Japan	WMHJ	Eleven metropolitan areas	2002–6	20+	4129	1682	55.1
New Zealandf	NZMHS	Nationally representative	2004–5	18+	12 790	7312	73.3
Northern Ireland	NISHS	Nationally representative	2005–8	18+	4340	1986	68.4
Poland	EZOP	Nationally representative	2010–11	18–64	10 081	4000	50.4
Portugal	NMHS	Nationally representative	2008–9	18+	3849	2060	57.3
Spain	ESEMeD	Nationally representative	2001–2	18+	5473	2121	78.6
Spain (Murcia)	PEGASUS-Murcia	Murcia region. Regionally representative	2010–12	18+	2621	1459	67.4
The Netherlands	ESEMeD	Nationally representative	2002–3	18+	2372	1094	56.4
The USA	NCS-R	Nationally representative	2001–3	18+	9282	5692	70.9
Total					73 376	37 846
IV. Total					138 801	71 239	70.1

^aThe World Bank (2009). Some of the WMH countries have moved into new income categories since the surveys were conducted. The income groupings above reflect the status of each country at the time of data collection. The current income category of each country is available at the preceding URL.

^bNSMH (The Colombian National Study of Mental Health); IMHS (Iraq 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); EMSMP (La Encuesta Mundial de Salud Mental en el Peru); CMDPSD (Comorbid Mental Disorders during Periods of Social Disruption); NSHS (Bulgaria National Survey of Health and Stress); MMHHS (Medellín Mental Health Household Study); LEBANON (Lebanese Evaluation of the Burden of Ailments and Needs of the Nation); M-NCS (The Mexico National Comorbidity Survey); RMHS (Romania Mental Health Survey); SASH (South Africa Health Survey); ESEMeD (The European Study Of The Epidemiology Of Mental Disorders); NHS (Israel National Health Survey); WMHJ2002-2006 (World Mental Health Japan Survey); NZMHS (New Zealand Mental Health Survey); NISHS (Northern Ireland Study of Health and Stress); EZOP (Epidemiology of Mental Disorders and Access to Care Survey); NMHS (Portugal National Mental Health Survey); PEGASUS-Murcia (Psychiatric Enquiry to General Population in Southeast Spain-Murcia);NCS-R (The US National Comorbidity Survey Replication).

^cMost 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, Poland, Spain-Murcia) used municipal, country resident or universal health-care 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 11 metropolitan areas and one random respondent selected in each sample household. 18 of the 28 surveys are based on nationally representative household samples.

^dThe 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. The weighted average response rate is 70.1%.

^ePeople's Republic of China.

^fFor the purposes of cross-national comparisons, we limit the sample to those 18+.

^gColombia moved from the ‘lower and lower-middle income’ to the ‘upper-middle income’ category between 2003 (when the Colombian National Study of Mental Health was conducted) and 2010 (when the Medellin Mental Health Household Study was conducted), hence Colombia's appearance in both income categories. For more information, please see footnote a.