Following the baseline interview, veterans randomized to the immediate entry group directly engaged in the Guitars for Vets Intervention and were interviewed at the end of the intervention period, roughly 6 weeks later. The intervention content and duration (6 weeks) was the same across both groups.

Those randomized to the delayed entry group had their baseline interview repeated at the end of the delayed entry period (4 weeks) prior to receiving the 6-week Guitars for Vets Intervention as well as after intervention completion. The intervention content and duration (6 weeks) was the same across both groups.

This was an active intervention providing veterans with an acoustic guitar, guitar pick, tuning instruments, a music book, practice CDs, and individual and group sessions of music instruction during a 6-week intervention period. Six tailored 1-hour individual guitar instruction sessions were scheduled (1 session per week). In addition to the 6 tailored individual lessons, the intervention provided 3 group sessions. Veterans were given a guitar that they could keep upon completion of the program. The same instructor was assigned to a subject for the duration of the study, and group sessions were supervised by the Education Director of Guitars for Vets.

Post-Traumatic Stress Disorder (PTSD) symptoms as measured by the PTSD Checklist Civilian (PCLC), a self-report scale that measures PTSD presence and severity. The 17 items correspond to Diagnostic and Statistical Manual DSM-IV symptoms of PTSD. The level of distress produced by each symptom is rated from 1 (not at all) to 5 (extremely). A score >50 on this measure is considered clinically significant (maximum score = 85).

Depression was assessed using the Beck Depression Inventory-II (BDI-II), a 21-item self-report scale measuring the presence and severity of depressive symptoms over the two weeks preceding test administration. Each answer ranges in score from 0-3. Total scores indicate minimal (0-13), mild (14-19), moderate (20-28), and severe (29-63; maximum = 63) levels of reported depression.