All 3 disorders are associated with experiencing or witnessing a life-threatening (or potential life-threatening) event or an event where there was actual or threatened harm to one’s physical safety.

The clinical criteria are very similar for both acute stress disorder (ASD) and post traumatic stress disorder (PTSD). The most distinguishing factor is the time criterion where acute stress disorder has onset immediately after the trauma and lasts between 3 days to 1 month compared to PTSD which is either a continuation of ASD or has first onset, not immediately afterwards, but within 6 months of the trauma.

Both disorders are characterised by re-experiencing symptoms, avoidance symptoms, physical and behavioural symptoms.

Both disorders were previously classified as anxiety disorders. This has recently been revised because both disorders are associated with prominent mood (anger, irritability or depressed mood) symptoms.

Treatment must include a combination of medication and psychotherapy to achieve optimal recovery.