The major feature of dissociative identity disorder is the existence of at least two different identities that alternately control a person’s behavior. Dissociative identity disorder is known as a rare disorder due to underdiagnosis and misdiagnosis. One of the presenting symptoms in dissociative identity is a suicide attempt. In this case, dissociative identity disorder and overdose drug intake, which emerges during the treatment of depression with fluoxetine, is identified. With regard to this complex case, the issues of overdose drug intake, suicide attempt, depression, antidepressant-associated suicide or side effects in dissociative disorder and their relations with each other will be discussed.