Brain scans as predictors of suicide
Suicide is this country’s 10th leading cause of death. Among teens and young adults, it is the second-leading cause of death. About half of those diagnosed with bipolar disorder, whose moods swing from manic to depressed, will make a suicide attempt and as many as one in five will die by their own hands. Yet, mental health practitioners have traditionally had only such subjective measures as patient interviews to gauge the risk of suicide. Now new imaging technologies can discern brain patterns that suggest an increased risk of suicide.
In a study of patients with bipolar disorder published in January, Yale researchers led by Hilary P. Blumberg, M.D., the John and Hope Furth Professor of Psychiatric Neuroscience, found three indicators linked to suicidal behavior that can be tracked through imaging technology.
“The identification of brain circuits involved in risk for suicide can lead to new ways to identify who is most at risk, and, hopefully, prevent suicides,” said Blumberg of the study published in The American Journal of Psychiatry.
In their study, researchers found that in teenagers and young adults with bipolar disorder who have made suicide attempts, white matter—the brain’s connective wiring—has decreased structural integrity in areas that regulate emotion. Those who attempted suicide also had less gray matter in the frontal-limbic system, where impulses and emotions develop, as well as in the frontal cortex, which helps regulate those feelings and behavioral responses. Researchers also observed a third difference. Using measurements of real-time blood flow between different areas of the brain, an indicator of connectivity and interaction among brain regions, they found that people who had attempted suicide at least once showed less connectivity between the limbic amygdala and the frontal cortex. “The findings suggest that the frontal cortex is not working as well as it should to regulate the circuitry,” Blumberg said. “That can lead to more extreme emotional pain, difficulties in generating alternative solutions to suicide, and greater likelihood of acting on suicidal impulses.”
Previous research has hinted at these findings, but with important exceptions, Blumberg said. First, very few imaging studies have been done in adolescents and young adults who have attempted suicide. Second, no research team thus far has studied suicide by evaluating patients via three imaging techniques—structural and functional MRIs and diffusion tensor imaging—taken in one sitting from a specialized MRI machine.
The next step will be to recruit individuals in other age groups as well as those with other mental disorders who are at risk of suicide, Blumberg said. The current study, though it showed significant differences between groups, was small. It included 26 participants diagnosed with bipolar disorder with at least one previous suicide attempt, 42 men and women with bipolar disorder with no history of suicide attempts, and 45 people in a healthy comparison group with no mental disorder diagnosis and no suicide history, all between ages 14 and 25.
In the burgeoning field of brain imaging, this study “is important because it identifies differences in brain areas that show who might be more likely to act on suicidal thoughts,” Blumberg said. Will MRI scans of a suicidal and non-suicidal person reveal differences? “We’re not there yet,” Blumberg said. “There are no established values in brain measurements.” That goal still remains the point of this research. Blumberg also noted that many paths lead toward suicide, from a weakened ability to self-regulate emotions to sudden tragic life events.
Blumberg and colleagues have already initiated research that follows adolescents over time to record brain changes correlated with suicide attempts, and they hope to pursue further study. This might also provide insight into the subjective experiences of suicide ideation and why those thoughts occur in the first place, she said. “Each day we lose people to suicide,” Blumberg said. “We try to go as fast as we can—it feels like we are racing against the clock.”