The effect of early trauma on suicidal vulnerability depends on fronto-insular sulcation

Improving our understanding of pathophysiology of suicidal behavior (SB) is an important step for prevention. Assessment of suicide risk is based on socio-demographic and clinical risk factors with a poor predictivity. Current understanding of SB is based on a stress-vulnerability model, whereby early-life adversities are predominant. SB may thus result from a cascade of developmental processes stemming from early-life abuse and/or neglect. Some cerebral abnormalities, particularly in fronto-limbic regions, might also provide vulnerability to develop maladaptive responses to stress, leading to SB. We hypothesized that SB is associated with interactions between early trauma and neurodevelopmental deviations of the frontal and insular cortices. We recruited 86 euthymic women, including 44 suicide attempters (history of depression and SB) and 42 affective controls (history of depression without SB). The early development of prefrontal cortex (PFC) and insula was inferred using 3D magnetic resonance imaging-derived regional sulcation indices, which are indirect markers of early neurodevelopment. The insula sulcation index was higher in emotional abused subjects; among those patients, PFC sulcation index was reduced in suicide attempters, but not in affective controls. Such findings provide evidence that SB likely traced back to early stages of brain development in interaction with later environmental factors experienced early in life.