Similar to PTSD (post-traumatic stress disorder) people who have once shared their life with a narcissist may go through corresponding occurrences resembling the symptoms of PTSD. Maybe we should call it PNSD or Post-Narcissist Stress Disorder.
Post-traumatic stress disorder develops after one has experienced an event or action that causes intense fear, disbelief, helplessness or horror.
While it is common to have a period of adjusting and coping after a narcissist, for many these periods of difficult adjustments may continue for quite a while. With time, attitude adjustment, letting go of the narcissist and giving the narcissism back to the narcissist (it is THEIR problem and ISSUE, no longer yours) and taking care of you, such traumatic reactions usually get better and dissipate completely.