Genetic influences on eight psychiatric disorders based on family data of 4 408 646 full and half-siblings, and genetic data of 333 748 cases and controls.

Psychol Med
Authors
Abstract

BACKGROUND: Most studies underline the contribution of heritable factors for psychiatric disorders. However, heritability estimates depend on the population under study, diagnostic instruments, and study designs that each has its inherent assumptions, strengths, and biases. We aim to test the homogeneity in heritability estimates between two powerful, and state of the art study designs for eight psychiatric disorders.

METHODS: We assessed heritability based on data of Swedish siblings (N = 4 408 646 full and maternal half-siblings), and based on summary data of eight samples with measured genotypes (N = 125 533 cases and 208 215 controls). All data were based on standard diagnostic criteria. Eight psychiatric disorders were studied: (1) alcohol dependence (AD), (2) anorexia nervosa, (3) attention deficit/hyperactivity disorder (ADHD), (4) autism spectrum disorder, (5) bipolar disorder, (6) major depressive disorder, (7) obsessive-compulsive disorder (OCD), and (8) schizophrenia.

RESULTS: Heritability estimates from sibling data varied from 0.30 for Major Depression to 0.80 for ADHD. The estimates based on the measured genotypes were lower, ranging from 0.10 for AD to 0.28 for OCD, but were significant, and correlated positively (0.19) with national sibling-based estimates. When removing OCD from the data the correlation increased to 0.50.

CONCLUSIONS: Given the unique character of each study design, the convergent findings for these eight psychiatric conditions suggest that heritability estimates are robust across different methods. The findings also highlight large differences in genetic and environmental influences between psychiatric disorders, providing future directions for etiological psychiatric research.

Year of Publication
2018
Journal
Psychol Med
Pages
1-8
Date Published
2018 Sep 17
ISSN
1469-8978
DOI
10.1017/S0033291718002039
PubMed ID
30221610
PubMed Central ID
PMC6421104
Links
Grant list
U01 MH109536 / MH / NIMH NIH HHS / United States
U01 MH109532 / MH / NIMH NIH HHS / United States
Wellcome Trust / United Kingdom
MR/L010305/1 / Medical Research Council / United Kingdom
U01 MH109528 / MH / NIMH NIH HHS / United States