Post-Traumatic Stress Disorder can occur after someone experiences a traumatic event such as combat, natural disasters like a tornado or earthquake, serious accidents, or physical attacks and abuse. Events such as these can cause great emotional upset, including extreme fear and feeling like you have no control over the situation.
It is normal for anyone who experiences a traumatic event to show changes in emotions and behavior. While these changes can be quite upsetting at the onset, these reactions generally lessen with time. If these changes last longer than three months, however, disrupt your work and family life, or cause great emotional distress, you may need to seek professional help.