Erik Erickson's Developmental Theory is the development of a person's ego identity. According to Erickson, “the sense of self-awareness that develops through social interaction” evolves a person's self-identity. Erickson's theory states that we go through eight stages and that in each of them we are faced with a conflict that can be resolved successfully or unsuccessfully. If left unresolved, the problem could resurface later in life and cause emotional problems. This theory gives the psychologist developmental stages to work with; For example, a psychologist would be able to look back at any Ericksonian stage and identify which developmental stage the person took unsuccessfully. Example; perhaps something happened during the patient's childhood phase (basic trust vs. distrust) where he was sexually abused which caused the patient to repress his childhood memories and then an event/experience traumatic later life brought on these repressed memories. I unfortunately saw this happen with a young teenage Marine who graduated high school and three months after graduating from boot camp he was sent straight to war. During the conflict, this young man had to kill to ensure his platoon returned safely to base camp. This represents a heavy responsibility for a young man, so early in his life. The young man continued to act in an exemplary manner and was eventually recognized by his command for his valiant actions. However, upon his return to the United States, the Marine's job performance began to decline, he was late for work, and alcohol was now regularly consumed. Once his command became aware of the Marines' actions, they thought it was post-traumatic stress disorder (PTSD). Syndrome, since the Marine was involved in several shootings during his stay in Iraq. After initial observations at our medical aid station, he was referred to our mental health office, which has five psychologists. Immediately after seeing the chief psychologist, it was reported that this young Marine was suffering from PTSD, but not from the war, but from sexual abuse by his stepfather when he was between 3 and 3 years old. years. 4.