Veterans Day is a time to remember the sacrifices of troops, and it’s a good time to remember the suffer many of them continue to endure due to post-traumatic stress disorder. An estimated 8 million Americans suffer from PTSD, including about 31 percent of Vietnam War veterans and 20 percent of Iraq veterans, and the rates just keep on rising.

But most people don’t have a good grasp on exactly what PTSD, and what it does to soldiers after they return home. As a result, many veterans find themselves stereotyped and misunderstood. So on Veterans Day, it’s good to educate yourself, or others, on just what PTSD is.

The reality is, most people can’t understand what a veteran has been through, and they may appear to be weak if they suffer mentally from things they’ve experienced in a war zone. Killing other human beings, and being nearly killed yourself, does something to one’s mind that can’t be understood by people who have never had to do these things.

“Going through trauma is not rare,” the U.S. Department of Veterans Affairs says on its website. “About 6 of every 10 men (or 60%) and 5 of every 10 women (or 50%) experience at least one trauma in their lives. Women are more likely to experience sexual assault and child sexual abuse. Men are more likely to experience accidents, physical assault, combat, disaster, or to witness death or injury.

“PTSD can happen to anyone. It is not a sign of weakness. A number of factors can increase the chance that someone will develop PTSD, many of which are not under that person’s control. For example, if you were directly exposed to the trauma or injured, you are more likely to develop PTSD.”