BACKGROUND AND INTRODUCTION During pregnancy, adverse maternal events that mount an immune response have been linked with neuropsychiatric disorders in the offspring. An imbalance between pro- and anti-inflammatory cytokines is suggested as a contributing mechanism to a child?s risk of neuropsychiatric disorders. In 2013, 41,149 individuals died by suicide in the United States. In that year, suicide was the third leading cause of death among children aged 10 to 14, and the second leading cause of death between the ages of 15 and 24. Evidence for the effectiveness of suicide prevention strategies are not convincingly positive. Moreover, a lack of understanding of suicide etiology limits our ability to predict who is at the greatest risk. This study shall link data from 52,966 children born to participants in the United States Collaborative Perinatal Project (CPP) between 1959-1966 to the National Death Index, determine their vital status through 2013, and investigate the prenatal, socioeconomic, behavioral, cognitive, and neurologic risks for completed suicide. We shall conduct a nested case-control study to investigate the contributions of gestational immune activity to fetal origins of suicide. The Division of Intramural Population Health Research (DIPHR) has identified 2371 serum specimens in the NICHD-DIPHR repository from CPP participants for which we shall compare levels of immune system biomarkers between offspring who died by suicide and a matched group of non-suicide controls. We hypothesize that there shall be a systematic pattern of differences between these groups, with cases exhibiting a pattern of biomarker concentrations consistent with a perturbation of the maternal immune system. SCOPE This task order shall use a Q-PlexTM Human Cytokine HS Screen (for 15 cytokines) and additional assays to detect immune system markers including but not limited to IL-8 and hsCRP.