Psychological trauma is the experience (in the client's perception) in which the individual has experienced a physically or psychologically (often life-) threatening situation, and the client has overwhelming psychological difficulty integrating this experience.

Typical examples of traumatic events are abuse, violence (or simply the threat thereof), or witnessing abuse and/or violence. Violent acts may also include natural disasters, accidents, war, etc. Trauma seems particularly disruptive when it occurs during childhood.

The term 'Posttraumatic Stress Disorder (PTSD)' first emerged after the Vietnam War, when many veterans were shunned upon their return from the war. Now, the term PTSD may apply to people who have experienced any number of traumatic events. Symptoms often include nightmares, avoidance of certain situations and places, depression, hypervigilance, etc. The therapist will consider all symptoms before making a diagnosis.