With respect to disorders... It depends on what you take to be fundamental to identity.

What used to be called axis II were thought to be more to do with identity insofar as they were unchanging through the lifespan. Personality disorders, as I mentioned before. Mental retardation. Think also of acquired. So... Personality changes or whatever resulting from an almighty whack to the head. Pole through the frontal lobes. Lobotomy.

Then think about memory... Memory used to be thought of as the crucial strand tying together self to self into the past... So interruptions to memory count as interruptions to the self. Think of how people fear Alzeheimers / dementia as a loss of themself... Then think of whacks to the head again... States of unconsciousness... Coma... And of course we have dissociative disorders and amnesia disorders in their various forms.

Depression... Loss of self? All the meaninful and valuable things... The love of life. The expression of self...

Mania... Not happiness... Extacy... Extreme emotions quite divorced from the rational self...

Schizophrenia used to be known as 'split personality'. Not a vertical split of different alters (contextual selves) but a vertical split of thought vs feeling vs behaviour. Disintegration between these parts of self...

*edit -- one of the above is regarded as 'vertical split' the other 'horizontal' i can't remember which way around or who made up that metaphor

Basically... Arguably... Every single item in the DSM could be construed as a disorder of the mind / self.

And... A whole bunch that are excluded due to being the result of substance or organic process, too...