Identifying Neurobiological Underpinnings of Two Suicidal Subtypes.

Despite substantial suicide prevention efforts, US suicide rates continue to climb, currently reaching about 14 per 100,000 individuals. Suicidal behavior has been linked to neurobiological, neurocognitive and behavioral factors; however, integrative, multi-modal studies are rare. Furthermore, prospective studies, crucial to understanding future risk factors, have focused on a single predictor and a single outcome, implying that suicidal behavior is homogeneous. But recent research shows suicidal behavior is complex and heterogeneous, with the possible existence of subtypes. The present report describes a project testing a model that posits two putative subtypes, using a prospective, multi-model design. The subtypes differ in regard to the patterns of suicidal ideation and underlying mechanisms. One hundred subjects diagnosed with a Major Depressive episode, half of whom have attempted suicide in the past, are enrolled and followed for two years, notably the highest risk period for suicidal behavior. Baseline assessments include a clinical assessment, neurocognitive and behavioral tasks, Ecological Momentary Assessments (EMA), PET imaging, and a cognitive emotion regulation task in the MRI scanner. The follow-up assessment includes a clinical assessment and EMA. The study findings have the potential to pave the way for a clearer understanding of suicidal ideation and behaviors and to improve our ability to treat those at risk for suicide by developing tailored approaches that will allow for more accurate pharmacological and psychosocial interventions.