Table 2

Studies of the association between ADHD and the DRD4 7-repeat allele

Study	Location	No. of probands	Diagnostic system	Test of association	Linkage	Statistic	p value^*
Case–control association studies

Mill et al58	United Kingdom	132	DSM-IV	χ²	+	OR = 6.2	0.01

Holmes et al30	United Kingdom	129	ICD-10, DSM-IV and DSM-III-R	χ²	+	OR = 1.9	0.001

Muglia et al59	Canada	66	DSM-IV	χ²	+	OR = 2.5	0.01

Comings et al60	United States	52	DSM-III-R and DSM-IV	χ²	+	χ² = 6.64	0.01

Rowe et al61	United States	70	DSM-IV	χ²	+	χ² = 5.9	< 0.05

Swanson et al62	United States	39	DSM-IV and ICD-10	χ²	+	χ² = 4.65	< 0.035

Castellanos et al63	United States	41	DSM-III-R	χ²	–	χ² = 0.06	0.81

La Hoste et al64	United States	39	DSM-IV	χ²	+	OR = 3.0	95% CI = 1.3–7.1

Family-based association studies
Roman et al28	Brazil	81	DSM-IV	HHRR	–	χ² = 0.37	0.54

Payton et al52	United Kingdom	103	ICD-10, DSM-IV and DSM-III-R	TDT	–	N/A	0.75

Mill et al58	United Kingdom	85	DSM-IV	TDT, HHRR	–	N/A

McCracken et al65	United States	371	DSM-IV	TDT	+	χ² = 5.4	0.02

Barr et al66	Canada	82	DSM-IV	TDT	+	χ² = 15.68	< 0.016

Holmes et al30	United Kingdom	110	ICD-10, DSM-IV and DSM-III-R	TDT	–	OR = 0.95	95% CI = 0.6–1.5

Kotler et al67	Israel	49	DSM-IV	HHRR	–	LR = 7.94	0.16

Muglia et al59	Canada	66	DSM-IV	TDT	+	z = 1.41	0.07

Hawi et al68	Ireland	78	DSM-IV	HHRR	–	χ² = 0.00	0.95

Tahir et al69	Turkey	104	DSM-IV	TDT	+	χ² = 2.79	0.05

Eisenberg et al70	Israel	49	DSM-IV	HHRR	–	χ² = 0.14	0.71

Faraone et al71	United States	54	DSM-IV	TDT	+	χ² = 7.4	0.007

Rowe et al61	United States	70	DSM-IV	TDT	–	χ² = 0.03	N/A

Smalley et al72	United States	129	DSM-III-R and DSM-IV	TDT	+	χ² = 4.85	0.03

Swanson et al62	United States	52	DSM-IV	HHRR	+	χ² = 4.65	< 0.035

Note: CI = confidence interval; LR = likelihood ratio.
↵* Unless otherwise indicated.