Psychological trauma is defined differently by psychologists than the general population.  It typically describes a life-threatening event, such as seeing someone badly injured or killed, thinking you might be badly injured or killed, or being harassed or assaulted or witnessing someone else harassed or assaulted.   This can take many forms, such as military experiences (e.g., combat service, a training injury, or military sexual trauma), sexual or physical harassment or assault, a car or motorcycle accident, or experiencing a natural disaster.

After a trauma, a traumatic stress reaction may occur resulting in symptoms such as reexperiencing the trauma, changes in bodily reactions, avoidance of reminders of the trauma, and changes in thoughts.  These typically begin to reduce in intensity and frequency over time until they disappear through a process of natural recovery.  However, for some people the symptoms persist, may even get worse over time, and begin to cause problems in their lives.  These symptoms might also intensify years or even decades after a trauma is experienced, often after a change in life pace such as a change in job or retirement.  That is when someone might receive a diagnosis of post-traumatic stress disorder (PTSD).  People with PTSD often state they no longer feel like themselves and are unable to engage comfortably in activities they used to do.  They also tend to experience associated concerns such as depression, anxiety, guilt, anger, and insomnia. At this point, psychological treatment is effective for understanding why natural recovery did not occur and to "kickstart" the natural recovery process to reduce symptoms and increase functioning and quality of life.

PTSD is not the only issue that may occur following a trauma.  Different constellations of symptoms may lead to receiving a different diagnosis.  However, effective treatment is available for all conditions.