Mood changes, even momentary ones, can significantly amplify the brain’s response to pleasure in people with bipolar disorder, according to recent research. This mental condition, characterized by extreme shifts in mood and energy levels, makes individuals more susceptible to a phenomenon researchers call “mood bias.”
This term describes how a good mood can cause someone to perceive experiences more positively, creating momentum in their mood.
“Imagine going to a new restaurant for the first time. If you’re in a fantastic mood, you’re likely to perceive the experience as better than it actually is,” explained Liam Mason from University College London’s Psychology and Language Sciences, co-lead author of the study published in the journal Biological Psychiatry Global Open Science.
The findings offer insight into why people with bipolar disorder can get caught in a “vicious cycle” of escalating moods, leading to riskier behavior. For the study, researchers scanned the brains of participants while they played a computerized version of the Roulette game. The study involved 21 participants with bipolar disorder and 21 without. The game required making bets on where a small ball would land on a spinning wheel.
Using functional Magnetic Resonance Imaging (fMRI), the researchers tracked brain responses to wins and losses, measuring how mood changes influenced ‘reward signals’ in the brain within seconds. They observed intense activity in the anterior insula, a brain region involved in mood changes, in both groups during the game.
However, only participants with bipolar disorder showed a heightened influence of ‘mood bias’ on their perception of wins and losses. In these participants, brain scans revealed intense activity in the striatum, a region associated with pleasurable experiences.
“In the control group, the insula and striatum were both active in unison, suggesting participants could maintain a balanced mood while perceiving rewards,” said Hestia Moningka, co-lead author from University College London’s Psychology and Language Sciences. “Meanwhile, participants with bipolar disorder showed the opposite; higher momentum in mood led to a stronger response to rewards, making it harder to separate their mood from how exciting they found the rewards.”
The study also found weaker communication between the anterior insula and the striatum in participants with bipolar disorder. These findings suggest that future interventions should focus on helping individuals with bipolar disorder better separate their mood from their perceptions and decisions, rather than just regulating mood and dampening positive experiences.
“New interventions that help people with bipolar disorder to better decouple their mood from their perception and decisions is an avenue we are looking into,” Moningka added.
