A nurse is caring for a client who has posttraumatic stress disorder (PTSD) after being physically assaulted. The client is unable to recall any details of the event. Which of the following defense mechanisms should the nurse recognize that the client is displaying?

A. Dissociation. Dissociation is a defense mechanism that causes a client to disconnect from thoughts, memories, feelings, or sense of identity in response to trauma. Clients with PTSD may experience memory gaps (dissociative amnesia) as a way to protect themselves from the emotional distress of the traumatic event. B. Rationalization. Rationalization involves justifying unacceptable behaviors or feelings with logical explanations to avoid true emotions. If the client were rationalizing, they might say, "The assault wasn’t that bad because I fought back." This does not explain memory loss related to PTSD. C. Undoing. Undoing is a defense mechanism where a person tries to reverse or "undo" a negative action or thought by performing an opposite behavior. For example, an individual who was aggressive toward someone might later be overly kind to compensate. This does not relate to memory loss. D. Reaction formation. Reaction formation occurs when a person expresses the opposite of their true feelings to cope with distress. For example, if the client felt fear from the attack but acted overly confident or dismissive about it, this would be reaction formation. However, it does not explain inability to recall details of the trauma.