Meta-analyses of genome-wide association studies for postpartum depression

Objective: Postpartum depression (PPD) is a common subtype of major depressive disorder (MDD) that is more heritable, yet is understudied in psychiatric genetics. The authors conducted meta-analyses of genome-wide association studies (GWASs) to investigate the genetic architecture of PPD. Method: Meta-analyses were conducted on 18 cohorts of European ancestry (17,339 PPD cases and 53,426 controls), one cohort of East Asian ancestry (975 cases and 3,780 controls), and one cohort of African ancestry (456 cases and 1,255 controls), totaling 18,770 PPD cases and 58,461 controls. Post-GWAS analyses included 1) single-nucleotide polymorphism (SNP)–based heritability (), 2) genetic correlations between PPD and other phenotypes, and 3) enrichment of the PPD GWAS findings in 27 human tissues and 265 cell types from the mouse central and peripheral nervous system. Results: No SNP achieved genome-wide significance in the European or the trans-ancestry meta-analyses. The of PPD was 0.14 (SE=0.02). Significant genetic correlations were estimated for PPD with MDD, bipolar disorder, anxiety disorders, posttraumatic stress disorder, insomnia, age at menarche, and polycystic ovary syndrome. Cell-type enrichment analyses implicate inhibitory neurons in the thalamus and cholinergic neurons within septal nuclei of the hypothalamus, a pattern that differs from MDD. Conclusions: While more samples are needed to reach genome-wide levels of significance, the results presented confirm PPD as a polygenic and heritable phenotype. There is also evidence that despite a high correlation with MDD, PPD may have unique genetic components. Cell enrichment results suggest GABAergic neurons, which converge on a common mechanism with the only medication approved by the U.S. Food and Drug Administration for PPD (brexanolone)

Filling Gaps On-Line: Use of Lexical and Semantic Information in Sentence Processing

Two experiments investigated how people assign an interpretation to question phrases. In order to determine the meaning of the WH-phrase (e.g., who, what), a "gap" must be located and the role associated with the gap assigned to the WH-phrase. Two experiments tested the Lexical Expectation model of Fodor (1978), according to which lexical properties of the verb determine when a gap is posited, and the All Resorts model of Stowe (1984), according to which all possibilities are considered and evaluated on their pragmatic appropriateness. In Experiment 1, subjects judged the meaningfulness of full sentences. The frequency with which verbs are used transitively determined whether there was an effect of the plausibility of the WH-phrase to act as an object of the verb. Effects of plausibility of the WH-phrase as an object showed up in just those cases where the object role should be assigned to the WH-phrase according to the Lexical Expectation model, rather than as predicted by the All Resorts model. In Experiment 2, these results were replicated using the word-by-word self-paced reading paradigm. The plausibility effect showed up at the verb itself when it is normally used transitively. This evidence suggests that a gap is preferred even over a lexically filled object for transitive expectation verbs