The term "narcissism" has been used in various psychological contexts, but was never officially a diagnostic category in the DSM. The DSM-III (1980) officially introduced and recognized "Narcissistic Personality Disorder" as a specific diagnosis with its own set of criteria for clinicians to use in their practice. This was not a case of "replacing" the term narcissism, but rather a formalization that allowed for a more precise diagnosis of this specific subset of personality disorder. In 1967-68, psychoanalysts Otto Kernberg and Heinz Kohut presented two early theories on narcissism. Kernberg described a "narcissistic personality structure," proposing three types of narcissism - normal adult narcissism, normal infantile narcissism, and pathological narcissism. Kohut presented the concept of "narcissistic personality disorder," arguing that narcissism is an essential aspect of normal development. Both contributed to the body of knowledge that ultimately shaped the definition and diagnostic criteria of NPD.