Not everyone will have the same symptoms, but diagnosis is usually based on the patient having at least one or two symptoms from each of four categories: re-experiencing, avoidance, arousal and reactivity, and cognition and mood. Here are some common ways these symptoms may appear: Flashbacks or repeatedly remembering or re-experiencing the accident. Nightmares, difficulty sleeping, or insomnia. Disturbing thoughts. Avoiding things that remind you of the accident, which may include people, places, objects, or experiences. Avoiding talking about the accident. Feeling anxious or tense. Having a strong or sensitive “startle” response. Outbursts of temper or other mood changes. Difficulties with memory, concentration, or cognition. Losing interest in activities you used to enjoy. Negative thoughts about yourself or life in general. Feeling guilt or responsibility for the accident even if it wasn’t your fault.