Reliving a disturbing or traumatic event—a violent encounter, the sudden death of a loved one—is a hallmark of post-traumatic stress disorder (PTSD), which shares some features with anxiety disorders. (Until very recently, in fact, PTSD was seen as a type of anxiety disorder rather than a stand-alone condition.)
But flashbacks may occur with other types of anxiety as well. Some research, including a 2006 study in the Journal of Anxiety Disorders , suggests that some people with social anxiety have PTSD-like flashbacks of experiences that might not seem obviously traumatic, such as being publicly ridiculed. These people may even avoid reminders of the experience—another symptom reminiscent of PTSD.