One particularly debilitating effect of stress is the development of post-traumatic stress disorder (PTSD). Post-traumatic stress disorder is caused by the experience or witnessing of traumatic or life-threatening events such as military combat, natural disasters, terrorist incidents, serious accidents, physical and emotional abuse, or violent personal assaults.

PTSD is complicated by the fact that it frequently occurs in conjunction with related disorders such as depression, substance abuse, problems of memory and cognition, and other physical and mental problems. The disorder is also associated with impairment of the person’s ability to function in social or family life, including occupational instability, marital problems, family discord and divorces. The impairment caused by PTSD substantially affects work, social, and family life.