The number of Veterans with PTSD varies by service era. The data below are from a large study of Veterans across the country:
| Service Era | PTSD in the Past Year | PTSD at Some Point in Life | |
| Operations Iraqi Freedom (OIF) and Enduring Freedom (OEF) | 15 out of 100 (15%) | 29 out of 100 (29%) | |
| Persian Gulf War (Desert Storm) | 14 out of 100 (14%) | 21 out of 100 (21%) | |
| Vietnam War | 5 out of 100 (5%) | 10 out of 100 (10%) | |
| World War II (WWII) and Korean War | 2 out of 100 (2%) | 3 out of 100 (3%) | |
| NOTE: The data in this table is from Veterans alive at the time of the study. As such, it does not include Veterans in any service area who have died and may have had PTSD. | |||