062_ Explore sex differences regarding clinical, neuropsychological and psychosocial variables in the Psycourse sample in patients with bipolar disorder and schizophrenia.
Research Question and Aims
Bipolar disorder (BD) and schizophrenia (SZ) are associated with neurocognitive impairments, even during periods of remission. Beyond clinical variables, other factors, such as sex, may contribute to neurocognitive performance in these disorders. Sex differences exist in terms of epidemiology, clinical phenomenology, course of illness, and other BD clinical characteristics as well as in patients with SZ and related psychoses. Interest in the study of sex differences in SZ and BD has increased considerably in recent decades, however evidence addressing sex differences in neurocognition in BD and SZ remains unclear given the limited number of studies published reporting conﬂicting results. Whereas some studies reported signiﬁcant sex effects on neuropsychological performance independent of group (i.e. healthy controls -HC- vs. patients) others found signiﬁcant diagnosis group by sex interaction indicating different neurocognitive patterns in BD and HC. The heterogeneity found across studies means that the results on the contribution of sex on neurocognitive differences should be treated with caution. The aim of the study will be to examine sex differences in neurocognition, psychosocial functioning and genetic risk in a large sample of patients with BD, SZ and healthy controls. Genetic variants are involved in the susceptibility to SCZ and BD. The genetic risk for BD or SCZ rarely depends on a single genetic alteration. Generally, many genetic variants, in the form of Single Nucleotide Polymorphisms (SNPs), contribute to the development of BD or SCZ. These genetic variants can be combined into a single polygenic risk score (PRS), that gives an idea of the cumulative genetic risk for BD or SCZ in a specific patient. A recent article has shown an association between the PRS and worse cognitive performance in mid- and old age, as well as worse school performance was seen in males only with no trend effects in females, indicating sex-specific effects of schizophrenia genetics on cognitive ability in healthy individuals across the entire lifespan.
Analysis will include the PsyCourse samples (patients with bipolar disorder and schizophrenia and healthy controls). Using these data we will investigate the association of sex with clinical and cognitive in order to define different profiles among bipolar and schizophrenic patients. Three groups (SZ, BD and controls) will be compared on clinical, neuropsychological and sociodemographic variables using linear and logistic models as appropriate and controlling for the presence of comorbidities/somatic disorder. MANOVA analysis will be performed to show overall differences in neuropsychological tests between groups. These analyses will be adjusted for relevant covariates. The following polygenic risk scores (PRS) will be calculated and included in the models: schizophrenia, bipolar disorder, major depressive disorder, educational attainment, cognitive performance. PRS-cs will be used for the weighting of the effect sizes in each respective discovery GWAS. PLINK 1.9 will be used for scoring and analyses will be run in R.
These analyses will be coordinated with PsyCourse proposal 009 in order to avoid/minimize overlapping approaches.
Genomics data: Raw genotypes (GSA chip) and imputed data from PsyCourse patients and healthy controls.