Changes in Brain Connectivity May Protect Against Bipolar Disorder

Why do some individuals develop bipolar disorder while their high-risk siblings do not? A new study has found that naturally occurring changes in brain wiring may help people at high genetic risk of developing bipolar avert the onset of the illness.

The study, conducted by researchers at the Icahn School of Medicine at Mount Sinai, opens up new avenues for researchers to begin investigating novel ways in which the brain can prevent disease expression, also known as resilience, with the hope of developing more effective treatments.

“A family history remains the greatest risk factor for developing bipolar disorder and while we often focus on risk, we may forget that the majority of those who fall into this category remain well,” said Dr. Sophia Frangou, M.D., Ph.D., professor of psychiatry at the Icahn School of Medicine at Mount Sinai and lead author of the study.

“Looking for biological mechanisms that can protect against illness opens up a completely new direction for developing new treatments. Our research should give people hope that even though mental illness runs in families, it is possible to beat the odds at the genetic lottery.”

Frangou’s ongoing research uses neuroimaging to investigate how differences in brain wiring can either increase or decrease the odds of developing mental illness.

Bipolar disorder is a mental illness characterized by strong fluctuations in patients’ mood, energy, activity levels and the ability to carry out everyday tasks. The illness is highly heritable, meaning that people with a parent or sibling with bipolar have a much greater risk of developing the disorder, compared with individuals with no family history.

For the study, the researchers used functional magnetic resonance imaging (fMRI) to map the connectivity patterns in the brains of three groups: patients with bipolar disorder, their siblings who did not develop the illness (resilient siblings), and unrelated healthy individuals.

During the brain scan, each participant was asked to perform an emotional and a non-emotional task that taps into two different types of brain function known to be affected by bipolar disorder.

The findings show that the resilient siblings and the patients have similar abnormalities in the connectivity of brain networks involved in emotional processing. However, the resilient siblings exhibited additional changes in brain wiring within these networks.

“The ability of the siblings to rewire their brain networks means they have adaptive neuroplasticity that may help them avoid the disease even though they still carry the genetic scar of bipolar disorder when they process emotional information,” said Frangou.

The findings are published online in the journal Translational Psychiatry.

Source: Mount Sinai Hospital