Background: Dissociation may be defined as a psychopathological process in which an individual’s psyche splits into two or more parts. The division of personality is a key element in trauma, especially if the patient is not able to cope with it. At least one part of personality may be relatively able to understand and function in the objective reality, whilst other part(s) of the psyche may be more or less disorganized, dysfunctional and less able to understand the truth. Methods: literature review; conceptualization of dissociation, dissociative disorders and partial psychosis from medical and philosophical perspective. Conclusion: The core of dissociation and dissociative disorders is usually psychological trauma, especially emotional trauma, although some individuals may experience dissociation without any obvious cause or trigger. Carefully designed trauma-focused psychotherapy and psychosocial support are considered and must be further studied as the cornerstone of multidisciplinary approach in the treatment of dissociative disorders. Dissociative identity disorder in its severe form may resemble characteristics of partial psychosis. Some patients suffering from partial psychosis have narcissistic personality traits, such as shamelessness, magical thinking, arrogance, envy, entitlement, exploitation and bad boundaries, and therefore, developing healthy self-love, which is based on healthy self-criticism, realistic thinking, humility, gratefulness, democratic behavior, altruism and good boundaries, might be helpful for these patients.