Psychiatric Disorders Are Genetically Connected

     Previously, psychiatric disorders have been defined by their symptoms over their genetics, yet the overlap of diagnosed individuals is no coincidence. Disorders such as schizophrenia, bipolar disorder, depression, anxiety, ADHD, and substance addiction often affect individuals of the same lineage. A study conducted by Andrew D. Grotzinger of the University of Colorado analyzes genetic data from over one million people to focus on these specific neurological disorders and to determine how distinct they are at a genetic level. 

    The researchers at University of Colorado found that many psychiatric conditions share substantial genetic risk. Most of the neurological disorders focused on did not have their own unique genetic signature as expected. Instead, the risk clusters into five major gene factors that span multiple disorders. For example, the article states "The two factors defined by (1) Schizophrenia and bipolar disorders (SB factor); and (2) major depression, PTSD and anxiety (Internalizing factor) showed high levels of polygenic overlap6 and local genetic correlation and very few disorder-specific loci". This means that schizophrenia and bipolar disorder share a genetic dimension related to psychosis whereas depression and anxiety cluster on a "mood related" genetic axis. Some dimensions capture shared risk for neurological and substance- abuse disorders. 

    Functionally, the shared genetic factors were related to specific biological annotations, including differential enrichment in brain regions, developmental time points, and cell type specific expression profiles. These findings using Genomic SEM suggest that psychiatric comorbidity shows convergence on partially shared pathways. 

    This article is an extreme step in furthering understanding of 14 different neurological disorders. Although the analysis is limited by ancestry, being that only European patients were used, it still provides significant framework for integrating genetics into psychiatric classifications.  

Sources: 

    Grotzinger, A. D., de la Fuente, J., Li, Z., Hansell, N. K., Stahl, E. A., Walters, R. K., Wray, N. R., et al. (2025). Genetic architecture of 14 psychiatric disorders at multiple levels of analysis. Nature, 621(7976), 134–142. https://doi.org/10.1038/s41586-025-09820-3

    Grotzinger, A., van der Zee, M., Rhemtulla, M., Ip, H., Nivard, M., & Tucker‑Drob, E. (2025). GenomicSEM: Structural equation modeling based on GWAS summary statistics https://github.com/GenomicSEM/GenomicSEM