TABLE 1.

World Mental Health (WMH) Survey sample characteristics^a

	Surveyb	Sample characteristicsc	Field dates	Age range	Sample size	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	(4,426)	87.7
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.	2002–3	18+	(6,752)	79.3
PRC – Beijing/Shanghai	B-WMH	Beijing and Shanghai metropolitan areas.	2002–3	18+	(5,201)	74.7
	S-WMH
PRC – Shenzhen	Shenzhen	Shenzhen metropolitan area. Included temporary residents as well as household residents.	2006–7	18+	(7,132)	80.0
Ukraine	CMDPSD	Nationally representative.	2002	18+	(4,724)	78.3
Total					(28,235)
II. Upper-middle income countries
Brazil	São Paulo Megacity	São Paulo metropolitan area.	2005–7	18+	(5,037)	81.3
Bulgaria	NSHS	Nationally representative.	2003–7	18+	(5,318)	72.0
Lebanon	LEBANON	Nationally representative.	2002–3	18+	(2,857)	70.0
Mexico	M-NCS	All urban areas of the country (approximately 75% of the total national population).	2001–2	18–65	(5,782)	76.6
Romania	RMHS	Nationally representative.	2005–6	18+	(2,357)	70.9
South Africa	SASH	Nationally representative.	2003–4	18+	(4,315)	87.1
Total					(25,666)
III. High income countries
Belgium	ESEMeD	Nationally representative. The sample was selected from a national register of Belgium residents	2001–2	18+	(2,419)	50.6
France	ESEMeD	Nationally representative. The sample was selected from a national list of households with listed telephone numbers.	2001–2	18+	(2,894)	45.9
Germany	ESEMeD	Nationally representative.	2002–3	18+	(3,555)	57.8
Israel	NHS	Nationally representative.	2002–4	21+	(4,859)	72.6
Italy	ESEMeD	Nationally representative. The sample was selected from municipality resident registries.	2001–2	18+	(4,712)	71.3
Japan	WMHJ2002–2006	Eleven metropolitan areas.	2002–6	20+	(4,129)	55.1
Netherlands	ESEMeD	Nationally representative. The sample was selected from municipal postal registries.	2002–3	18+	(2,372)	56.4
New Zealande	NZMHS	Nationally representative.	2003–4	18+	(12,790)	73.3
N. Ireland	NISHS	Nationally representative.	2004–7	18+	(4,340)	68.4
Spain	ESEMeD	Nationally representative.	2001–2	18+	(5,473)	78.6
United States	NCS-R	Nationally representative.	2002–3	18+	(9,282)	70.9
Total					(56,825)	71.4
IV. Total					(110,726)

^aThe World Bank. (2008). Data and Statistics. Accessed May 12, 2009. Available at: http://go.worldbank.org/D7SN0B8YU0

^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); CMDPSD (Comorbid Mental Disorders during Periods of Social Disruption); NSHS (Bulgaria National Survey of Health and Stress); 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); NMHS (Portugal National Mental Health Survey); 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 United States 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 unclustered sample, with households randomly selected in each of the 11 metropolitan areas and one random respondent selected in each sample household. Of the 22 surveys, 15 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 71.4%.

^eNew Zealand interviewed respondents 16+ but for the purposes of cross-national comparisons, we limit the sample to those 18+.