I assume a person can end up with multiple personality by having social withdrawal.
For a person who does not like the people surrounding, he or she can withdraw intellectually and emotionally (if he or she knows how). I believe by keep repeating this process will cause split or multiple personality.
By not interacting with others, we might find ourselves being little more than a reflection of the people who we have needed. Thus, a feeling of being multiple people.
I can kind of relate. DID involves amnesiac barriers to conceal trauma, so there wouldn’t be any of that going on. But my mind definitely has a stronger tendency to come alive and talk to itself (myself, whatever) when I’ve been alone for a while.