Table 2.

HRs and 95% CIs comparing the risk for ADHD in exposed and unexposed children by timing and type of antipsychotic exposure

	Number with ADHD/N	Person-years at risk	Hazard ratio (95% CI)
			Crude	Model 1*	Model 2†
Antipsychotic exposure
Unexposed	71775/4 308 620	41 863 339	1.00 (Reference)	1.00 (Reference)	1.00 (Reference)
Exposed anytime during pregnancy	482/15 466	130 211	2.28 (2.08 to 2.49)	2.00 (1.83 to 2.19)	1.10 (1.00 to 1.21)
Timing of antipsychotic exposure
First trimester only	210/6478	56 144	2.17 (1.90 to 2.49)	1.72 (1.51 to 1.97)	1.07 (0.93 to 1.23)
Second/third trimester only	103/3349	28 534	2.24 (1.84 to 2.72)	2.09 (1.72 to 2.54)	1.08 (0.89 to 1.32)
First trimester and second/third trimester	169/5639	45 534	2.45 (2.10 to 2.85)	2.46 (2.11 to 2.85)	1.06 (0.90 to 1.25)
Type of antipsychotic exposure
Typical antipsychotics only	272/6896	75 179	1.84 (1.63 to 2.08)	1.71 (1.51 to 1.93)	1.11 (0.98 to 1.26)
Atypical antipsychotics only	166/7752	48 100	3.11 (2.67 to 3.62)	2.40 (2.06 to 2.79)	1.00 (0.85 to 1.17)

*Adjusted for source country, birth year, sex of child, maternal age, and parity.

†Adjusted for source country, birth year, sex of child, maternal age, parity, maternal education, cohabitation, mother born within source country, BMI, smoking, maternal comorbidity, use of known teratogens, use of suspected teratogens, other medications during pregnancy.

ADHD, attention-deficit/hyperactivity disorder; BMI, body mass index; CI, confidence interval; HR, hazard ratio.