Posted Wednesday, April 06, 2011
Recent studies suggest the number of children and teens being treated for bipolar disorder has increased dramatically over the last decade, yet experts say there is much that is still unknown about the brain mechanisms that play a role in this disorder.
But new work from Bradley Hospital researchers sheds new light on the disorder by showing that bipolar youth have intrinsic brain activation changes – a discovery that could someday help clinicians make more accurate diagnoses and lead to more effective treatments.
Previous brain imaging studies have compared the brain function of children with bipolar disorder to their healthy peers during certain tests of attention, decision-making and in response to facial expressions. But recent work shows that only five percent of the brain’s energy is spent on such cognitive or emotional processes. This new study by Bradley researchers is the first study ever to use a state-of-the-art method to evaluate how the brain spends the other 95 percent in children with bipolar disorder.
“Functional MRI paired with cognitive and emotional tasks is a very important tool to help us understand how bipolar disorder affects children’s brains and behavior,” said lead author Daniel P. Dickstein, M.D., director of Bradley Hospital’s Pediatric Mood, Imaging and Neurodevelopment (Pedi-MIND) program. “But this new method that we used in our study, which is called resting state functional connectivity, allows us to examine how the brain spends 95 percent of its energy on intrinsic, spontaneous activity.”
According to Dickstein, the study was the first to use this technique in children and adolescents with bipolar disorder. “We found that children with bipolar disorder have significantly different brain activity while they are at rest compared to typically-developing kids in both the frontal and temporal lobes of the brain – areas that are generally associated with personality, behavior and language,” he said. “These findings suggest that some brain changes associated with bipolar disorder in children and adolescents are intrinsic, or hard-wired – meaning they cut across many traditional domains of cognitive or emotional function. So we are now working to see if these hard-wired changes are specific to bipolar disorder, or if children with other psychiatric problems have them as well.”
The findings were recently published in the journal Biological Psychiatry.
Bipolar disorder is characterized by dramatic and frequent mood swings that alternate between euphoria, elation and irritability – the manic phase of the disorder – and severe depression. Although bipolar disorder often begins in late adolescence or early adulthood, it can develop as early as the preschool years. There is no laboratory test for bipolar disorder, or any other psychiatric illness. Instead, establishing a diagnosis is based entirely on detailed clinical history, which is often more difficult to obtain when dealing with children.
In the Bradley Hospital study, researchers scanned 15 children between the ages of 7 and 17 with bipolar disorder and 15 of their healthy peers using functional magnetic resonance imaging (fMRI), a non-invasive technique that localizes brain activity. Unlike more traditional fMRI studies that measure activity while people are performing a cognitive or emotional task, such as making decisions or responding to facial expressions, this study tested intrinsic brain activity while the children were instructed to relax.
Based on previous research, Dickstein and his team focused on three brain areas: the left dorsolateral prefrontal cortex (DLPFC), which is involved in decision-making; amygdala, which processes emotions; and accumbens, which plays a central role in the area of the brain associated with rewards and pleasure.
“Today, clinicians have to rely entirely on a child’s clinical history, questionnaires and interviews with parents to diagnose pediatric bipolar disorder, which can be challenging,” said Dickstein. “Identifying brain-based markers of pediatric bipolar disorder that could supplement the child’s clinical history will ultimately help clinicians make more accurate diagnoses, develop more targeted treatments and possibly allow us to help children at an earlier age.”
Filed under: Bradley, Bradley Hasbro Children's Research Center,