Table 1.

WMH sample characteristics by World Bank income categories^a

Country by income category	Surveyb	Sample characteristicsc	Field dates	Age range	Sample size		Response rated
					Part 1	Part 2
I. Low- and 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
India	WMHI	Pondicherry region.	2003–5	18–97	2992	1373	98.8
Nigeria	NSMHW	Twenty-one 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	18–100	6752	2143	79.3
PRC	B-WMH	Beijing and Shanghai metropolitan areas.	2002–3	18–70	5201	1628	74.7
Ukraine	S-WMH CMDPSD	Nationally representative.	2002	18–91	4724	1720	78.3
Total					24 095	9245
II. Upper-middle-income countries
Brazil	São Paulo Megacity	Stratified multistage clustered area probability sample of household residents in the São Paulo metropolitan area.	2005–7	18–93	5037	2942	81.3
Bulgaria	NSHS	Nationally representative.	2003–7	18–98	5318	2233	72.0
Lebanon	LEBANON	Nationally representative.	2002–3	18–94	2857	1031	70.0
Mexico	M-NCS	Stratified multistage clustered area probability sample of household residents in 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	18–96	2357	2357	70.9
South Africae	SASH	Nationally representative.	2003–4	18–92	4315	4315	87.1
Total					25 666	15 240
III. High-income countries
Belgium	ESEMeD	Nationally representative. The sample was selected from a national register of Belgium residents.	2001–2	18–95	2419	1043	50.6
France	ESEMeD	Nationally representative. The sample was selected from a national list of households with listed telephone numbers.	2001–2	18–97	2894	1436	45.9
Germany	ESEMeD	Nationally representative.	2002–3	18–95	3555	1323	57.8
Israel	NHS	Nationally representative.	2002–4	21–98	4859	4859	72.6
Italy	ESEMeD	Nationally representative. The sample was selected from municipality resident registries.	2001–2	18–100	4712	1779	71.3
Japan	WMHJ 2002–2006	Eleven metropolitan areas. Although samples from a clustered household sample, there was no within-household clustering due to setting the sampling fraction so that some households were skipped after enumeration because residents fall below the specified sampling fraction	2002–6	20–98	4129	1682	55.1
Netherlands	ESEMeD	Nationally representative. The sample was selected from municipal postal registries.	2002–3	18–95	2372	1094	56.4
New Zealande	NZMHS	Nationally representative.	2003–4	18–98	12 790	7312	73.3
Northern Ireland	NISHS	Nationally representative.	2004–7	18–97	4340	1986	68.4
Portugal	NMHS	Nationally representative.	2008–9	18–81	3849	2060	57.3
Spain	ESEMeD	Nationally representative.	2001–2	18–98	5473	2121	78.6
United States	NCS-R	Nationally representative.	2002–3	18–99	9281	5692	70.9
Total					60 673	32 387
IV. Total					110 434	56 872	70.8

^aWorld Bank (2008).

^bNSMH (The Colombian National Study of Mental Health), WMHI (World Mental Health India), 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), WMHJ 2002–2006 (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 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, and 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, and 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. Sixteen of the 23 surveys are based on nationally representative (NR) 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 70.8%.

^eSouth Africa and New Zealand interviewed respondents 16+ but for the purposes of cross-national comparisons we limit the sample to those 18 + .