Table 1. Prevalence of DSM-IV IED ^a in the World Mental Health surveys.

Country	Lifetime prevalence	12-month prevalence	30-day prevalence	12-month prevalance of IED among lifetime cases	30-day prevalence of IED among 12-month cases	Sample size used, n
Low–lower middle-income countries	0.6 (0.1)	0.4 (0.0)	0.3 (0.0)	60.1 (3.8)	70.4 (5.0)	36 498
Colombia	1.2 (0.2)	0.5 (0.1)	0.4 (0.1)	41.9 (6.1)	75.7 (10.0)	4426
Iraq	0.4 (0.2)	0.4 (0.2)	0.3 (0.1)	93.9 (6.1)	86.6 (10.9)	4332
Nigeria	0.1 (0.0)	0.0 (0.0)	0.0 (0.0)	79.6 (20.7)	25.9 (27.2)	6752
Peru	0.6 (0.2)	0.2 (0.1)	0.2 (0.1)	37.7 (10.3)	72.1 (13.6)	3930
PRC China	0.5 (0.1)	0.3 (0.1)	0.2 (0.1)	52.8 (13.9)	71.5 (13.5)	5201
PRC Shen Zhen	0.7 (0.1)	0.6 (0.1)	0.4 (0.1)	83.9 (5.7)	63.7 (10.8)	7132
Ukraine	1.1 (0.2)	0.6 (0.1)	0.4 (0.1)	56.3 (7.9)	69.7 (9.9)	4725
Upper-middle-income countries	0.7 (0.1)	0.3 (0.1)	0.2 (0.0)	48.3 (5.6)	71.6 (6.7)	19 884
Brazil	0.7 (0.1)	0.4 (0.1)	0.2 (0.1)	53.0 (10.8)	49.5 (14.2)	5037
Bulgaria	0.2 (0.1)	0.2 (0.1)	0.1 (0.1)	68.8 (17.2)	84.6 (11.4)	5318
Lebanon	0.6 (0.1)	0.3 (0.1)	0.2 (0.1)	44.4 (12.6)	89.9 (10.9)	2857
Romania	0.5 (0.2)	0.3 (0.2)	0.3 (0.2)	66.0 (18.7)	93.1 (7.3)	2357
South Africab	1.2 (0.3)	0.5 (0.2)	0.3 (0.1)	37.9 (9.6)	70.9 (9.0)	4315
High-income countries	1.1 (0.1)	0.6 (0.1)	0.3 (0.0)	51.4 (3.8)	52.2 (4.4)	31 681
Japan	0.4 (0.1)	0.2 (0.1)	0.1 (0.0)	66.6 (11.8)	39.5 (16.2)	4129
Northern Ireland	1.1 (0.2)	0.4 (0.1)	0.3 (0.1)	31.7 (7.5)	76.2 (12.2)	4340
Poland	0.2 (0.0)	0.1 (0.0)	0.0 (0.0)	49.4 (13.2)	36.0 (16.4)	10 081
Portugal	0.5 (0.1)	0.3 (0.1)	0.1 (0.1)	45.9 (11.7)	46.3 (24.0)	3849
USA	2.7 (0.2)	1.5 (0.2)	0.8 (0.1)	55.0 (4.8)	51.9 (5.0)	9282
All countries combined	0.8 (0.0)	0.4 (0.0)	0.3 (0.0)	53.6 (2.5)	61.9 (3.2)	88 063
WHO regionsc
Region of the Americas	1.6 (0.1)	0.8 (0.1)	0.5 (0.1)	51.7 (3.7)	55.4 (4.4)	22 675
African region	0.5 (0.1)	0.2 (0.1)	0.1 (0.1)	40.1 (9.1)	66.1 (9.8)	11 067
Western Pacific region	0.6 (0.1)	0.4 (0.1)	0.3 (0.1)	72.5 (6.0)	61.7 (8.1)	16 462
Eastern Mediterranean region	0.5 (0.1)	0.3 (0.1)	0.3 (0.1)	69.0 (9.8)	87.7 (8.2)	7189
Western European region	0.9 (0.1)	0.3 (0.1)	0.2 (0.1)	35.9 (6.3)	64.8 (13.0)	8189
Eastern European region	0.4 (0.0)	0.2 (0.0)	0.2 (0.0)	57.8 (6.1)	69.6 (7.0)	22 481
Comparison between countries	${\chi }_{16}^2=21.9$, p < 0.001*	${\chi }_{16}^2=7.9$, p < 0.001*	${\chi }_{16}^2=8.3$, p < 0.001*	${\chi }_{16}^2=2.4$, p = 0.002*	${\chi }_{16}^2=1.4$, p = 0.153
Comparison between low-, middle- and high-income country groups	${\chi }_2^2=19.1$, p < 0.001*	${\chi }_2^2=5.5$, p = 0.044*	${\chi }_2^2=0.9$, p = 0.405	${\chi }_2^2=2.0$, p = 0.133	${\chi }_2^2=4.3$, p = 0.014*
Comparison between WHO regions	${\chi }_5^2=26.1$, p < 0.001*	${\chi }_5^2=8.3$, p < 0.001*	${\chi }_5^2=5.4$, p < 0.001*	${\chi }_5^2=4.1$, p = 0.001*	${\chi }_5^2=1.5$, p = 0.186

Data are given as percentage (standard error).

DSM-IV, Diagnostic and Statistical Manual of Mental Disorders, fourth edition; IED, intermittent explosive disorder; PRC, People's Republic of China; WHO, World Health Organization.

^aThe definition of IED in this study conforms to the ‘narrow’ definition used in prior reports from the World Mental Health Surveys but with the additional criterion of some degree of interference in functioning.

^bThe higher South African estimate in the paper by Fincham et al. (2009) was not calculated by the World Mental Health Data Coordination Centre and is incorrect: http://www.hcp.med.harvard.edu/wmh/ftpdir/Fincham_et_al_2009_erratum.pdf

^cRegion of the Americas (Colombia, Brazil, Peru, USA); African region (South Africa, Nigeria); Western Pacific region [PRC Shen Zhen, PRC China (Beijing and Shanghai), Japan]; Eastern Mediterranean region (Iraq, Lebanon); Western European region (Northern Ireland, Portugal); Eastern European region (Romania, Poland, Bulgaria, Ukraine).

^*p < 0.05; two-sided test.