Global Study Identifies 36 Genes Linked to Bipolar Disorder

BARCELONA, Spain — An international study published in the journal Nature on January 22, 2025, has identified 36 genes involved in the onset and development of bipolar disorder, marking the largest genetic study on the condition to date. The research, led by the Bipolar Disorder Working Group, involved over 800 researchers from 40 countries, including professionals from IDIBAPS-Hospital Clínic and Hospital Vall d’Hebron, both affiliated with CIBER de Salud Mental (CIBERSAM).

Bipolar disorder, a chronic mental illness affecting 40 to 50 million people worldwide, is characterized by alternating episodes of depression and mania or hypomania. The disorder has a substantial genetic basis, with heritability estimated between 60% and 80%. However, pinpointing specific genes has been challenging due to the condition’s complexity, which involves both genetic and environmental factors.

The study conducted a meta-analysis of genome-wide association studies, comparing the genes of 158,000 patients with bipolar disorder to 2.8 million individuals without the condition. For the first time, the research included participants from all six inhabitable continents, ensuring a diverse and comprehensive dataset.

Researchers identified 337 genome-wide significant (GWS) variants, grouped into 298 specific regions of the genome. This discovery is four times larger than any previous study. These variants are linked to brain plasticity, signal transmission, and the disorder’s underlying causes. Using advanced genetic mapping techniques, the team pinpointed 36 reliable genes associated with bipolar disorder.

The study also revealed genetic differences between bipolar disorder subtypes. Type 1 bipolar disorder showed a stronger genetic link to schizophrenia, while type 2 was more closely associated with major depressive disorder and attention deficit hyperactivity disorder (ADHD).

Dr. Eduard Vieta, head of Hospital Clínic’s Psychiatry Service and the IDIBAPS research group, emphasized the study’s significance: ‘With this study, we have taken a big step forward to better understand how this disorder functions and what causes it. Given a little more time, we also hope to develop new and better treatments for it.’

The findings, published under the title ‘Characterising the genetic landscape of bipolar disorder yields novel biological insights,’ provide a foundation for future research and potential therapeutic advancements.