After a trauma, it is normal to be in shock, to have painful memories and to become upset by reminders of the trauma. Thinking may also be negative and exaggerated. For most, these reactions lessen over time. For some, reactions continue and are severe.

PTSD symptoms usually appear soon after trauma. For most people, these symptoms go away on their own within the first few weeks and months after the trauma. For some, the symptoms can last for many years, especially if they go untreated.

PTSD symptoms can stay at a fairly constant level of severity. Individuals may have periods when symptoms are not very intense and other times when symptoms flare up. PTSD symptoms can worsen during times of stress or when trauma survivors are reminded of the trauma. How long PTSD lasts may also depend on whether effective treatment is received.