Answer:
PTSD
Explanation:
Post Traumatic Stress Disorder is a condition developed by many people who experienced a traumatic event in the past.
It can be a death of a loved one, a shocking or a scary event o a prolonged exposure to a dangerous situation (as fighting in a war).
Some people recover from the initial symptoms ( sadness, helplessness, flashbacks, anxiety) within 6 months after the event. Some people, however, never recover fully and may need medical help and some medication.