​Traumatic stress is a normal response to events that are overwhelming and frightening, they may leave the person feeling powerless and helpless. They may occur as a one-of event or a series of events. Common examples may be:

• violence or abuse (e.g. assaults, emotional, physical or sexual abuse in adulthood or childhood)
• accidents (e.g. road traffic accident, negligence, house fires, burglary)
• natural disasters, terror attacks, combat stress

Other traumatic events that may be deemed more typical life events include:

• bereavement and loss (death of a loved one, miscarriage, redundancy, loss of health or end of relationship)
• bullying or shaming experiences
• intoxication or psychotic experiences (events while intoxicated or under a psychotic experience)

Common responses to traumatic events:

• flashbacks and reliving past events
• intrusive thoughts and feelings
• nightmares and sleep disturbance
• being easily startled and being hyper-alert for danger
• sexual disturbance or performance issues
• difficulty concentrating 
• emotional responses: guilt, anger, depression, low self esteem
• suicidal thoughts
• self harm to cope with distress (injuring self, excessive alcohol or drug use)

Treatment of traumatic stress:

• understanding how trauma effects the brain and keeps the threat system on alert for danger
• learning strategies for tolerating distress and managing feelings

Trauma and the brain: The UK Trauma Council have produced a good video that explains trauma.