Association between mitochondria-related genes and cognitive performance in the PsyCourse Study
(2023)
Older Adults with Bipolar Disorder (OABD) represent a heterogeneous group, including those with early and late onset of the disorder. Recent evidence shows both groups have distinct clinical, cognitive, and medical features, tied to different neurobiological profiles. This study explored the link between polygenic risk scores (PRS) for bipolar disorder (PRS-BD), schizophrenia (PRS-SCZ), and major depressive disorder (PRS-MDD) with age of onset in OABD. PRS-SCZ, PRS-BD, and PRS-MDD among early vs late onset were calculated. PRS was used to infer posterior SNP effect sizes using a fully Bayesian approach. Demographic, clinical, and cognitive variables were also analyzed. Logistic regression analysis was used to estimate the amount of variation of each group explained by standardized PRS-SCZ, PRS-MDD, and PRS-BD. A total of 207 OABD subjects were included (144 EOBD; 63 LOBD). EOBD showed higher PRS-BD compared to LOBD (p = 0.005), while no association was found between age of onset and PRS-SCZ or PRS-MDD. Compared to LOBD, EOBD individuals also showed a higher likelihood for suicide attempts (p = 0.01), higher presence of psychotic symptoms (p = 0.003), higher prevalence of BD-I (p = 0.002), higher rates of familiarity for any psychiatric disorder (p = 0.004), and lower processing speed measured with Trail-Making Test part A (p = 0.03). OABD subjects with an early onset showed a greater genetic burden for BD compared to subjects with a late onset. These findings contribute to the notion that EOBD and LOBD may represent different forms of OABD, particularly regarding the genetic predisposition to BD.
Background
Employment and relationship are crucial for social integration. However, individuals with major psychiatric disorders often face challenges in these domains.
Aims
We investigated employment and relationship status changes among patients across the affective and psychotic spectrum – in comparison with healthy controls, examining whether diagnostic groups or functional levels influence these transitions.
Method
The sample from the longitudinal multicentric PsyCourse Study comprised 1260 patients with affective and psychotic spectrum disorders and 441 controls (mean age ± s.d., 39.91 ± 12.65 years; 48.9% female). Multistate models (Markov) were used to analyse transitions in employment and relationship status, focusing on transition intensities. Analyses contained multiple multistate models adjusted for age, gender, job or partner, diagnostic group and Global Assessment of Functioning (GAF) in different combinations to analyse the impact of the covariates on the hazard ratio of changing employment or relationship status.
Results
The clinical group had a higher hazard ratio of losing partner (hazard ratio 1.46, P < 0.001) and job (hazard ratio 4.18, P < 0.001) than the control group (corrected for age/gender). Compared with controls, clinical groups had a higher hazard of losing partner (affective group, hazard ratio 2.69, P = 0.003; psychotic group, hazard ratio 3.06, P = 0.001) and job (affective group, hazard ratio 3.43, P < 0.001; psychotic group, hazard ratio 4.11, P < 0.001). Adjusting for GAF, the hazard ratio of losing partner and job decreased in both clinical groups compared with controls.
Conclusion
Patients face an increased hazard of job loss and relationship dissolution compared with healthy controls, and this is partially conditioned by the diagnosis and functional level. These findings underscore a high demand for destigmatisation and support for individuals in managing their functional limitations.
Although lipid biology may play a key role in the pathophysiology of mental health disorders such as schizophrenia (SCZ) and bipolar disorder (BD), the nature of this interplay and how it could shape phenotypic presentation, including cognitive performance is still incompletely understood. To address this question, we analyzed the association of plasma level of different lipid species with cognitive performance in the transdiagnostic PsyCourse Study. Plasma lipidomic profiles of 623 individuals (188 SCZ, 243 BD, 192 healthy controls) belonging to the PsyCourse Study were assessed using liquid chromatography and untargeted mass spectrometry. The association between 364 annotated lipid species from 16 lipid classes and six cognitive tests was evaluated. Likewise, the association of polygenic risk scores (PRS) for SCZ, BD, executive function (EF), and educational attainment (EA) with lipid plasma levels were also investigated. In the regression analysis, three lipid species belonging to phosphatidylethanolamine plasmalogen and one belonging to ceramide class showed significant negative association with Digit-Symbol test scores. Lipid class-based enrichment analysis in LipidR replicated the significance of the phosphatidylethanolamines class for the Digit-Symbol test, which evaluates the processing speed in cognitive tasks. Polygenic load for SCZ, BD, EF, or EA was not associated with lipid levels. Our findings suggest a link between lipids and cognitive performance independent of mental health disorders. Still, independent replication is warranted to better understand if phosphatidylethanolamines could represent an actionable pharmacologic target to tackle cognitive dysfunction, an important unmet clinical need that affects long-term functional outcomes in individuals with severe mental health disorders.
Alterations in glial cell function and cytokine levels in the central nervous system may be influenced by neuroinflammatory processes, which have a pathogenic role in psychiatric disorders. Variability in genes that encode inflammatory mediators is associated with risk of developing mental disorders. Therefore, by analyzing data from the transdiagnostic PsyCourse Study, we aimed to investigate whether variations in inflammatory mediator genes are associated with current symptom severity.
We used cross-sectional data from 1320 individuals with a psychiatric disorder and 466 neurotypical individuals. Outcome variables were the psychopathological data from various rating scales and questionnaires that measured depressive, psychotic, and manic symptoms. Furthermore, from a whole-genome SNP array dataset, we extracted single nucleotide polymorphisms (SNPs) in the loci of genes related to inflammatory mediators, and we performed an association analysis by considering covariates. False discovery rate (FDR) was used to adjust the results for multiple comparisons.
A total of 1594 individuals and 1336 SNPs were included in the analyses. The results of regression analysis showed a significant positive association of six SNPs located on the interleukin (IL)-1 receptor type 1 (IL-1R1) gene locus with Altman Self-Rating Mania Scale scores (FDR-adjusted p value < 0.05).
Our findings show that genetic variations in IL-1R1 may influence the pathophysiology of psychiatric disorders by affecting brain cytokine profiles associated with manic episodes. IL-1R1 encodes a membrane-bound receptor for IL-1. Several physiological functions, including inflammation, are linked to the IL-1/IL-1R1 signaling pathway. Replication of our findings is warranted.
