Fragmentation describes a state of the self that is the opposite of cohesion. It is a diagnostic sign.
This notion appeared in Heinz Kohut's 1968 article "The Psychoanalytic Treatment of Narcissistic Personality Disorders." A sign of the narcissistic personality, as compared with the neuroses, fragmentation triggers disintegration anxiety, a counterpart of castration anxiety. The fragmentation corresponding to the auto-erotic stage is total in psychosis, in contrast to the narcissistic personality, in which the self is cohesive. In narcissism, transient fragmentation is seen during analysis and during certain periods when the self is vulnerable, such as adolescence.
This notion was developed throughout Kohut's work, becoming one of the four fundamental concepts of self psychology set forth in "Remarks about the Formation of the Self" (1974). To Kohut, narcissistic pathology tends to be progressively reduced to variations in the state of the self, which is fragmented at the preoedipal and oedipal levels. Fragmentation of the self triggers an intensification of the drives, which are redefined as products of the disintegration of the self in the service of its restoration.
Fluctuations in the state of the self are important clinical data for diagnosis and treatment, but the drives become secondary to the self.