Direct Link Between Insulin Resistance and Behavioral Disorders Found

In a study recently published in the journal PNAS, researchers from the Joslin Diabetes Center discovered one potential explanation for reasons why people with diabetes are more prone to anxiety and depression compared to those with other chronic diseases that require similar levels of management. By genetically modifying mice to make their brains resistant to insulin, scientists first found that the animals exhibited behaviors that suggested anxiety and depression, and then pinpointed a mechanism that lowers levels of a key neurotransmitter, dopamine, in areas of the brain associated with those conditions. “This is one of the first studies that directly shows that insulin resistance in the brain actually can produce a behavioral change,” said the senior author of the study. Further examining the brains of the mice, scientists also found altered metabolism in mitochondria, which produce energy for cells. Among the changes, the mitochondria increased production of two enzymes that degrade dopamine. Although the mice were releasing a normal amount of dopamine, chance in the mitochondria meant that they metabolized the dopamine more quickly. “We think that contributes to these behaviors, and in fact when we give the mice antidepressants that work by slowing dopamine degradation, we can correct some of the behavioral changes,” said the senior author. Previous research in both mice and humans has made connections between insulin resistance and other neurodegenerative conditions. To read more about this study, click here.