Date of Award

Summer 8-15-2021

Author's School

Graduate School of Arts and Sciences

Author's Department

Psychology

Degree Name

Doctor of Philosophy (PhD)

Degree Type

Dissertation

Abstract

Rates of suicide have steadily increased across all age cohorts, revealing a particularly concerning rise in suicide among much younger age groups (10-15 years old). Recent efforts aimed at understanding suicide in youth have leveraged work from the adult literature to more pointedly examine candidate risk factors associated with childhood suicide. A noteworthy body of work has begun to clarify the role that impulsivity plays in elevating suicide risk among adults and adolescents, a critical link warranting further research in childhood suicide given the vast and well-documented changes occurring in self-control and brain maturity throughout development. Here, we examined a large and representative sample of children endorsing lifetime suicide ideation (N= 849), suicide attempt (N=186), and no history of suicide (N=10,754) from the Adolescent Brain and Cognitive Development Study, with a particular interest in delineating group differences in 1) cognitive measures of impulsivity (i.e., set-shifting, working memory, inhibition); 2) personality measures of impulsivity (i.e., five trait impulsivity dimensions) and; 3) several properties of brain organization relevant to self-control (i.e., whole-brain topology, network topology of control networks, and connector hubs). Using multilevel modeling to account for the tiered nature of our dataset (Level 1: Child; Level 2: Family; Level 3: Site), our findings revealed that suicide ideation was marked by broad elevations in trait impulsivity while suicide attempt was better characterized by a dual profile of set-shifting deficits and elevations in urgency measures in girls (only elevated urgency measures in boys). Behavioral profiles in attempters were accompanied by disruptions in several connector hubs, with greatest evidence for altered hubness in the dorsolateral prefrontal cortex (DLPFC) of the frontoparietal network (FPN) relative to ideators. These hub profiles, however, did not emerge as a mechanism by which impulsivity distinguished ideators from attempters, underscoring a dominant view that the shift from ideation to attempt is likely characterized by a complex and interacting profile of emotional, cognitive, environmental, and neural variables. Together, these findings provide supporting evidence for the roles that impulsivity and frontoparietal regions play in suicide ideation and attempt during childhood, overall extending adolescent- and adult-like profiles of suicide into much younger periods of development.

Language

English (en)

Chair and Committee

Deanna M. Barch

Committee Members

Desiree White, Josh Jackson, Nico Dosenbach, Joan Luby,

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