Orbitofrontal cortex response to angry faces in men with histories of suicide attempts

Objective: The authors sought to elucidate the functional neural basis of the neurobiological abnormalities underlying the vulnerability to suicidal behavior. Method: Event-related functional MRI was used to measure neural activity in response to angry and happy versus neutral faces. Thirteen currently euthymic men with a history of major depressive disorder and suicidal behavior were compared with 14 currently euthymic men with a history of major depressive disorder but not of suicidal acts (affective comparison subjects) and 16 healthy male comparison subjects. Results: Relative to affective comparison subjects, suicide attempters showed greater activity in the right lateral orbito-frontal cortex (Brodmann's area 47) and decreased activity in the right superior frontal gyrus (area 6) in response to prototypical angry versus neutral faces, greater activity in the right anterior cingulate gyrus (area 32 extending to area 10) to mild happy versus neutral faces, and greater activity in the right cerebellum to mild angry versus neutral faces. However, activation in these frontal regions did not differ between healthy individuals and either patient group. Relative to healthy comparison subjects, both patient groups showed reduced activity in the right cerebellum to neutral faces and to mild happy versus neutral faces. Conclusions: Suicide attempters were distinguished from nonsuicidal patients by responses to angry and happy faces that may suggest increased sensitivity to others' disapproval, higher propensity to act on negative emotions, and reduced attention to mildly positive stimuli. These patterns of neural activity and cognitive processes may represent vulnerability markers of suicidal behavior in men with a history of depression.