Assortative Mating—A Missing Piece in the Jigsaw of Psychiatric Genetics

Effects of autozygosity and schizophrenia polygenic risk on cognitive and brain developmental trajectories

“…To interpret their findings, Power et al 7 hypothesized that positive assortative mating in couples with better cognitive profiles could partly explain the mentioned association. Observations from other independent reports support the hypothesis of differential assortative mating patterns influencing cognitive, behavioral and psychiatric phenotypes [9][10][11][12][13][14] , which is possibly the most plausible framework to explain the findings from Power et al 7 and the current report. Importantly, further research is needed since both research outcomes indicate relatively small effect sizes which might have been shadowed by unpublished findings.…”

“…While two studies 6,8 suggest that inbreeding depression may decrease adult intelligence, divergent results by Power et al 7 could be explained in view of three evidences. First, assortative mating has recently been highlighted as an important factor underlying psychiatric and behavioral phenotypes [9][10][11][12] , in line with specific findings showing assortative mating in relation to cognitive ability published in the late 20 th century 13,14 genetic effects on brain structure and function, but the evidence of associations between genetic risk for schizophrenia and brain features is scarce, with some studies reporting no overlap between schizophrenia PGRS and subcortical phenotypes derived from magnetic resonance imaging (MRI) 21 ,…”

“…With this background, using a sample of 4183 young participants (ages [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] with Europeanancestry from the PNC, we pursue the following four main aims. First, the putative links between multivariate genome-wide features (ROH burden and schizophrenia PGRS, computed independently) and both intellectual abilities and neuroanatomical features are tested.…”

Associations between loneliness and personality are mostly driven by a genetic association with Neuroticism

“…This relationship can arise when there is pleiotropy, when there is a causal relationship between the two traits (mediated pleiotropy), and when there is cross‐trait assortative mating between loneliness and Neuroticism. Cross‐trait assortative mating has been reported between several psychiatric disorders (Maes et al, ; Plomin, Krapohl, & O'Reilly, ; Van Grootheest et al, ), but it was not significantly different from zero between loneliness and Neuroticism in a relatively large sample, making this an unlikely explanation for the genetic correlation. The results of the longitudinal cross‐lagged analyses suggest that a causal relationship may be present, which is likely to explain at least part of the strong genetic correlation between loneliness and Neuroticism.…”

Evaluating the Impact of Nonrandom Mating: Psychiatric Outcomes Among the Offspring of Pairs Diagnosed With Schizophrenia and Bipolar Disorder

“…Evidence is strong that nonrandom mating occurs for psychiatric traits (1)(2)(3)(4) as it does for features such as height, personality, and IQ (5)(6)(7), with recent epidemiological work illustrating pervasive spousal resemblance within and across major diagnostic groups (8). Such findings have renewed questions about the impact nonrandom mating may have on the transmission dynamics and population maintenance of psychiatric disorders (9,10).…”