Table 4.

Risks of Schizophrenia, Bipolar Disorder, and Schizoaffective Disorder in OCD-Unaffected Relatives of Individuals With OCD (Exposed) Compared With Relatives of Individuals Without OCD (Unexposed)

	Risk of Schizophrenia			Risk of Bipolar Disorder			Risk of Schizoaffective Disorder
	Exposed	Unexposed	RRs (CIs)	Exposed	Unexposed	RRs (CIs)	Exposed	Unexposed	RRs (CIs)
	n (%)			n (%)			n (%)
First-degree relatives
Parents	26 (0.19)	114 (0.09)	2.2 (1.5–3.4)	38 (0.28)	207 (0.16)	1.8 (1.3–2.5)	11 (0.08)	54 (0.04)	2.0 (1.1–3.6)
Children	125 (0.39)	750 (0.24)	1.6 (1.4–2.0)	248 (0.77)	1512 (0.48)	1.6 (1.4–1.9)	60 (0.19)	403 (0.13)	1.5 (1.1–1.9)
Full siblings	114 (0.51)	533 (0.24)	2.1 (1.7–2.6)	138 (0.62)	728 (0.33)	1.9 (1.6–2.2)	39 (0.18)	262 (0.12)	1.5 (1.1–2.0)
All first-degree relatives	265 (0.39)	1397 (0.21)	1.9 (1.6–2.1)	424 (0.63)	2447 (0.37)	1.7 (1.6–1.9)	110 (0.16)	719 (0.11)	1.5 (1.2–1.8)
Second-degree relatives
Maternal half-siblings	18 (0.41)	102 (0.29)	1.3 (0.8–2.2)	27 (0.61)	142 (0.40)	1.6 (1.1–2.3)	4 (0.09)	47 (0.13)	0.6 (0.2–1.6)
Paternal half-siblings	18 (0.32)	143 (0.32)	0.9 (0.6–1.5)	23 (0.41)	160 (0.36)	1.3 (0.8–1.9)	7 (0.13)	48 (0.11)	1.1 (0.5–2.4)
All half-siblings	37 (0.37)	253 (0.27)	1.3 (0.9–1.8)	52 (0.51)	380 (0.41)	1.3 (1.0–1.7)	11 (0.11)	98 (0.11)	1.0 (0.5–1.8)
All second-degree relativesa	329 (0.47)	2399 (0.35)	1.4 (1.2–1.5)	342 (0.49)	2758 (0.40)	1.2 (1.1–1.4)	121 (0.17)	1008 (0.15)	1.2 (1.0–1.4)
Third-degree relatives
Cousins	149 (0.20)	1091 (0.15)	1.4 (1.2–1.6)	258 (0.34)	2049 (0.27)	1.3 (1.1–1.4)	70 (0.09)	511 (0.07)	1.4 (1.1–1.7)

Note: Abbreviations are explained in the first footnote to table 1. Statistically significant RRs are highlighted in bold.

^aSecond-degree relatives include half-siblings, grandparents, grandchildren, uncles/aunts, and nephews/nieces.