Anti-Social/ Dissociative Personality Disorder

DID may lead to discrete states that can take identities of their own, alternate personalities. Changes between these personalities are described as "switching". In many cases, each "alter" performs a certain role for the host.

Antisocial personality disorder is characterized by a long standing pattern of disregard for other's rights, often crossing the line and violating those rights. The Zodiac could have began experiencing this during his childhood into his early teens.