Table 1.

Characteristics of study participants

Characteristic	AD-exposed n=8,833	(%)	AD-not exposed n=646,782	(%)	P-valued
Maternal age at conception					<0.001
<21 years	373	4.2	25,869	4.0
21–25 years	1,564	17.7	125,783	19.4
26–30 years	3,044	34.5	259,853	40.2
31–35 years	2,669	30.2	178,433	27.6
≥36 years	1,183	13.4	56,844	8.8
Paternal age at conception					<0.001
<25 years	1,071	12.1	75,696	11.7
26–30 years	2,388	27.0	211,695	32.7
31–35 years	2,587	29.3	209,555	32.4
≥36 years	2,371	26.8	136,072	21.0
Data missing	416	4.7	13,764	2.1
Parental psychiatric historya					<0.001
Yes	1,897	21.5	17,853	2.8
No	6,523	73.8	615,251	95.1
Data missing	413	4.7	13,678	2.1
Gestational age at birth					<0.001
<28 weeks	17	0.2	1,215	0.2
28–31 weeks	99	1.1	4,526	0.7
32–36 weeks	723	8.2	35,870	5.5
≥37 weeks	7,994	90.5	605,171	93.6
Birth weight					<0.001
<2,500 g	631	7.1	31,640	4.9
2,500–2,999 g	1,291	14.6	71,513	11.1
3,000–3,499 g	2,903	32.9	196,827	30.4
≥3,500 g	3,973	45.0	343,054	53.0
Data missing	35	0.4	3,748	0.6
Sex					0.41
Boy	4,587	51.9	331,523	51.3
Girl	4,246	48.1	315,244	48.7
Data missing	0	0.0	15	0.0
Congenital malformationb					<0.001
Yes	459	5.2	25,160	3.9
No	8,374	94.8	621,622	96.1
Parity					0.70
0	3,780	42.8	279,513	43.2
>1	5,053	57.2	367,263	56.8
Data missing	0	0.0	6	0.0
Affective disorder (mother)c					<0.001
Yes	1,756	19.9	4,324	0.7
No	7,077	80.1	642,458	99.3
Affective disorder (father)c					<0.001
Yes	159	1.8	3,195	0.5
No	8,261	93.5	629,909	97.4
Data missing	413	4.7	13,678	2.1
Autism spectrum disorder
Yes	104	1.2	5,333	0.8
No	8,729	98.8	641,449	99.2
Childhood autism
Yes	37	0.4	2,030	0.3
No	8,796	99.6	644,752	99.7

Notes:

^aOne or both parents diagnosed with a psychiatric disorder before birth of the child (except maternal affective disorder) (ICD-8: 290–315 and ICD-10: All F-codes)

^bchild diagnosed with congenital malformations (ICD-10: Q0–99 codes, except for Q53 and Q65; see text)

^cparent diagnosed with an affective disorder before birth of the child (ICD-8: 296.09, 296.19, 296.29, 296.39, 296.99, 298.09, 298.19, 300.49, 301.19 and ICD-10: F30–F34 and F38–F39)

^dtest for no association between characteristic and exposure group.

Abbreviations: AD, antidepressants; n, number.