Little bit of  anxiety is normal in stressful situations.But anxiety is “abnormal “ if it :-

• Is out of proportion to the stressful situation
• Persists when the stressful situation has gone or the stress is minor
• Appears for no apparent reason when there is no stressful situation

Panic disorder & agoraphobia: An acute intense attack of anxiety accompanied by feelings of impending doom is known as panic disorder.Patients with panic disorder present with a number of comorbid conditions ,most commonly agoraphobia,which refers to a fear or anxiety regarding places from which escape might be difficult.

Specific pobia & social phobia: A  specific phobia is a strong,persisting fear of an object or situation whereas a social phobia is a strong,persisting fear of situations in which embarrassment can occur.

Post traumatic stress disorder (PTSD) & Acute stress disorder: In PTSD,the person is exposed to a traumatic event that involves actual or threatened death or serious injury,or at hreat to the physical integrity of self or others.

• The person’s response involves intense fear,helplessness or horror.
• The traumatic event is persistently rexperienced as flashbacks.
• Persistence avoidance of stimuli associated with the  trauma
• Persistant symptoms of increased arousal like difficulty in sleeping,irritability,anger,difficulty in concentrating,etc.
• duration of the disturbance is more than a month

Acute stress disorder is similar to PTSD ,but which occurs earlier than PTSD (within 4 weeks of the event ) and remits within 2 days to 4 weeks of the event.