Chances are pretty good that you’re familiar with the term post-traumatic stress disorder, commonly known as PTSD. PTSD has long been recognized as a psychiatric condition that can develop in the wake of trauma. But in recent years, experts have begun using a separate, less well-known term—complex PTSD (C-PTSD)—to describe the distinct mental health challenges that can result specifically from prolonged and repeated traumatic events, and they say understanding the differences is key when it comes to effective treatment.

So what should providers and concerned loved ones know about C-PTSD? How do its symptoms differ from those of PTSD? And what types of trauma are most often associated with it?