Participants were military veterans of Operations Enduring Freedom and Iraqi Freedom. Exclusion criteria were a history of seizures, serious medical illness (including prior cerebrovascular accident or myocardial infarction), acute suicide risk, current psychotic disorder, bipolar disorder, or cognitive disorder due to general medical condition, pregnancy, metal implant, shrapnel, aneurysm clip, or pacemaker, and moderate or severe TBI. To avoid potential genetic confounds related to ancestry, the sample was limited to genetically-confirmed White non-Hispanic individuals. We did not have adequate statistical power in our sample to conduct analyses with other ethnically-homogenous groups. Only participants with viable functional neuroimaging data were analyzed. Study approval was obtained from all relevant Institutional Review Boards and regulatory committees. Participants provided written informed consent and were compensated financially.
