Signs of PTSD include flashbacks, severe anxiety, nightmares and a persistent feeling of fear. According to CCOHS, other common symptoms include feeling on edge, angry or numb; feeling that something terrible will happen soon; being dissatisfied at work; having trouble concentrating; and using drugs or alcohol to cope.
PTSD is diagnosed by a doctor, psychiatrist, or psychologist based on a personal interview. In order to be diagnosed, a person must display a certain set of symptoms for at least one month. The set of symptoms must include one symptom related to re-experiencing the event like nightmares or flashbacks.