Table 1.

WMH sample characteristics by World Bank income categories^a

						Sample size
Country by income category	Surveyb	Sample characteristicsc	Field dates	Age range	Response rated	Total	With MDD
I. High-income countries
Israel	NHS	Nationally representative.	2002-4	21-98	72.6	4,859	284
Japan	WMHJ2002-2006	Eleven metropolitan areas.	2002-6	20-98	55.1	4,129	219
New Zealandf	NZMHS	Nationally representative.	2003-4	18-98	73.3	12,790	1,908
N. Ireland	NISHS	Nationally representative.	2004-7	18-97	68.4	4,340	423
Portugal	NMHS	Nationally representative.	2008-9	18-81	57.3	3,849	379
United States	NCS-R	Nationally representative.	2002-3	18-99	70.9	9,282	1,562
Total					67.9	(39,249)	(4,775)
II. Upper-middle income countries
Brazil – São Paulo	São Paulo Megacity	São Paulo metropolitan area.	2005-7	18-93	81.3	5,037	408
Bulgaria	NSHS	Nationally representative.	2003-7	18-98	72.0	5,318	283
Lebanon	L.E.B.A.N.O.N	Nationally representative.	2002-3	18-94	70.0	2,857	267
Mexico	M-NCS	All urban areas of the country (approximately 75% of the total national population).	2001-2	18-65	76.6	5,782	397
Romania	RMHS	Nationally representative.	2005-6	18-96	70.9	2,357	54
Total					74.8	(21,351)	(1,409)
III. Low and lower-middle income countries
Colombia	NSMH	All urban areas of the country (approximately 73% of the total national population)	2003	18-65	87.7	4,426	476
Iraq	IMHS	Nationally representative.	2006-7	18-96	95.2	4,332	193
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	18-100	79.3	6,752	176
PRCe – Beijing/Shanghai	B-WMH/S-WMH	Beijing and Shanghai metropolitan areas.	2002-3	18-70	74.7	5,201	151
PRCe – Shenzhenf	Shenzhen	Shenzhen metropolitan area. Included temporary residents as well as household residents.	2006-7	18-88	80.0	7,132	452
Ukrainef	CMDPSD	Nationally representative.	2002	18-91	78.3	4,724	629
Total					81.4	(32,567)	(2,077)

^aThe World Bank. (2012). Data. Accessed June 5, 2012 at: http://data.worldbank.org/country.

^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); 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 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) 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 11 metropolitan areas and one random respondent selected in each sample household. 19 of the 26 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 73.7%.

^ePeople's Republic of China

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