Erik Erickson's developmental theory is the development of a person's ego identity. According to Erickson, “the conscious sense of self that develops through social interaction” evolves a person's ego identity. Erickson's theory states that we go through eight stages and that in each we face a conflict that can be resolved successfully or unsuccessfully. If resolved unsuccessfully, it may recur later in life and cause emotional problems. This theory provides the psychologist with developmental stages to work with; For example, a psychologist would be able to trace back any Erickson stage and pinpoint which developmental stage the person has unsuccessfully completed. Example; perhaps something happened during the patient's childhood phase (basic trust vs. mistrust) in which he was sexually abused, which led the patient to repress his childhood memories, then a traumatizing event/experience later in his life brought those repressed memories. Unfortunately I saw this happen to a young teenage Marine who graduated from high school and within 3 months of graduating from boot camp, was sent straight to war. During the conflict this young man had to kill to ensure that his platoon returned safely to base camp. There are many responsibilities that a young person must take on, so early in their life. The young man continued to perform exemplary and was eventually recognized by his command for his valiant actions. However, upon returning to the United States, the Marine's job performance began to decline, he was late to work, and alcohol was regularly abused. Once his command learned of the Marines' actions, they thought it was post-traumatic stress (PTSD). Syndrome, since the Marine was involved in several firefights during his stay in Iraq. After initial observations by our medical care center, he was referred to our mental health office, where five psychologists work. Soon after seeing the chief psychologist it was reported that this young Marine was suffering from PTSD, but not from the war, but from having been sexually abused by his stepfather when he was between the ages of 3 and 3 years. 4.