Modulating Impulsivity in Suicidal Adolescents With tDCS

Suicide is one of the leading causes of death in adolescence. To improve the ability to
predict and prevent suicidal behavior, there is a pressing need for research in this area to
advance beyond identifying risk factors toward a greater focus on the mechanisms of risk for
this behavior. In particular, elucidating the neural pathways underlying risk for suicidal
behavior is important insofar as such work may yield specific and modifiable targets for
clinical intervention. The adoption of new experimental paradigms providing experimental
control over potentially modifiable risk factors has been recommended as a means of
meaningfully advancing the field in this regard. Although yet to be applied to the study of
suicidality, transcranial direct current stimulation (tDCS), in conjunction with measures of
electroencephalography (EEG) and event-related potentials (ERPs), may hold promise as an
experimental paradigm in the study of potentially modifiable risk factors, and underlying
neural mechanisms, for suicidality. One such risk factor of particular relevance to suicide
in adolescence is state-sensitive aspects of impulsivity. Impulsivity has been consistently
linked with suicidality, with this association appearing to be stronger in adolescence than
adulthood. As a first step toward investigating whether modulation of impulsivity and
associated neural pathways may yield clinically meaningful changes in risk for adolescent
suicidal behavior, the R21 is a proof-of concept study evaluating the potential for tDCS
targeting brain regions associated with behavioral impulsivity (right inferior frontal gyrus
[rIFG]) and cognitive impulsivity (left orbitofrontal cortex [lOFC]) to modulate these facets
of impulsivity in a sample of adolescent suicide attempters. Participants will be randomly
assigned to receive anodal tDCS over the rIFG, anodal tDCS over the lOFC, or a sham
stimulation condition, in a three-group design. Task-based measures of behavioral and
cognitive impulsivity will be administered before and after tDCS or sham stimulation.
Additionally, EEG and ERP data will be collected during the impulsivity tasks, and
resting-state EEG data will be collected pre- and post-tDCS administration to confirm
engagement of the targeted brain regions and to delineating the neural pathways underlying
the effects of tDCS on impulsivity.

Inclusion Criteria:

- have attempted suicide prior to admission

- speak and read English fluently

- do not display evidence of significant cognitive impairment, based on a standard
psychiatric exam as well as school records on admission

- are not actively psychotic at time of intake.

Exclusion Criteria:

- a significant general medical condition

- history of seizure, head injury, brain surgery or tumor

- intracranial metallic implants or implanted electrical devices

- substance abuse or dependence in the past six months.