. Author manuscript; available in PMC: 2022 Jan 5.

Published in final edited form as: Am J Med Genet B Neuropsychiatr Genet. 2020 Aug 19;183(7):403–411. doi: 10.1002/ajmg.b.32814

TABLE 2.

Correlations and heritabilities in the Schizophrenia group

	Age of onset (AOO)	SANS	SAPS	Cognition	Community functioning
Phenotypic correlation with AOO		−0.196 (.003)^*	−0.228 (.045)^*	0.295 (.030)^*	0.318 (.008)^*
Genetic correlation with AOO		−1.00 (.007)^*	−1.00 (.296)	1.00 (.150)	1.00 (.590)
Bivariate heritability with AOO^a		−0.447	−0.258	0.337	0.124
Environmental correlation with AOO		1.00 (.078)	0.103 (.889)	−0.106 (.840)	0.248 (.388)
Heritability^b	0.198 (.277)	0.977 (<.001)^*	0.853 (.003)^*	0.835 (.013)^*	0.320 (.182)

Note: p value in parentheses. Analyses were conducted in SOLAR using the t-distribution function and age and sex as covariates. Higher SANS and SAPS scores indicate more severe symptoms and higher cognition and community factor scores indicate better functioning.

Bivariate heritability (also known as standardized genetic covariance) is calculated by multiplying the square root of the heritability of the first phenotype by the square root of the heritability of the second phenotype by the genetic correlation (e.g., h of age of onset * h of negative symptoms * R_g of age of onset and negative symptoms). The individual heritabilities are estimated within a model that contains both phenotypes (i.e., they differ slightly from the univariate phenotypes presented in the table above). Bivariate heritability therefore captures the total genetic effect explained by the two phenotypes.

Univariate heritability.

Significant at p = .05.