Summarize this article in one sentence.
Someone may feel a constant sense of danger or fear or be reminded of painful memories when experiencing PTSD. It's common to be going along with one's day then suddenly feel the sting of a painful memory or suddenly feel threatened out of the blue. A person may be grocery shopping, then suddenly have memories of gunshots or being hurt in war. Having unpleasant dreams can be a symptom of PTSD. A person with PTSD may wake up distressed from dreams that re-experience the trauma or evoke similar feelings of trauma. The dreams may be distressing both during and after waking. Some people feel as if they are experiencing the trauma just as it happened before. It can feel like the trauma is being relived or as if the trauma is happening once again. When experiencing a flashback, a person may be out of touch with the current reality and get lost in the memory, believing it to be occurring right now. Some people may be extra sensitive to events or things that remind them of the event. This may include anniversaries, places, or people that trigger difficult memories. The triggers can be physical or psychological. A psychological trigger may be experiencing a similar emotions state as right before or during the trauma, but interpreting it as the same event. A physical trigger could be the location or things associated with the trauma. Reminders of the event may cause severe distress and upset. It may be easier to avoid thoughts and feelings connected to the traumatic event. To someone with PTSD, engaging in thoughts or feelings from the traumatic event may feel too overwhelming, so avoidance is used instead. A person may detach or avoid interacting with people that serve as reminders of the event, or avoid places that were associated with the trauma. Engaging in activities, people, places, or thoughts related to the trauma may feel too heavy and it may feel easier to avoid these thoughts altogether.
Notice intrusive thoughts or memories. Observe nightmares. Monitor flashbacks. Note reminders of the event. Observe avoiding thoughts or behaviors.