PTSD ... or post-traumatic stress disorder ... means you have stressful symptoms or memories after a traumatic or life-threatening event.

It can be caused by many things, such as a natural disaster, military combat, a bad wreck, or sexual abuse or assault.

Symptoms can start soon after the event or they may come months or even years later.

These symptoms may not go away over time, and they can make your daily life ... like your work, or relationships ... very hard to deal with.

[sound of footsteps, radio chatter, helicopter] [Justin] "PTSD makes your world feel very small. You isolate yourself ... and feel trapped, and it's not a good place to be."

[sound of clock ticking, music box] [doorbell rings] [Meredith] "I had a hard time getting close to people ... something in me was broken."

PTSD can cause different types of symptoms.

For example, you may feel like you're reliving the event, through flashbacks, nightmares, or memories that feel very real.

[sound of clock ticking] [Meredith] "The nightmares were the worst. I barely slept.

I hated being alone at night."

[Justin] "I'd hear a loud car [sound of car backfire] or a firecracker, and it would send me right back there into the desert."

[sound of helicopter, radio chatter] Another common symptom is avoiding people, places, or situations that trigger the memory.

[sound of police sirens] [Angie] "I planned my whole day around avoiding traffic. It affected my job.

My kids would get annoyed with me. I had no social life."

[Justin] "I stayed away from crowds, so I'd go to the store late at night, or wouldn't go at all.

One time I just lost it and had to get out of there."

You also may feel very on edge, like you're in danger ... or feel angry or nervous a lot.

You may blame yourself for the trauma or have a hard time remembering it ... or feel like the world is a dangerous place.

[Justin] "There was a threat around every corner.

And I was constantly on guard, planning how to defend myself [tires screech] ... and my family.

It was exhausting. And it scared the kids."

[Angie] "I hated going anywhere.

Getting behind the wheel felt like I was having a heart attack."

And the stress from PTSD can lead to other problems, like depression, or using alcohol or drugs.

[Meredith] "Alcohol was a way to escape the pain, but over time it just made things worse."

If any of these symptoms or stories sound familiar, you might benefit from treatment.

Treatment can help you get better, so you can feel more in control and more like yourself again.