There are many kinds of insane, martin. And having symptoms of a condition does not mean you have the actual condition. Especially since many of the symptoms and early indicators of dissociative identity disorder are also symptoms and indicators of a couple dozen other mental illnesses. And who is going to to do an in depth psych profile of a dragon? Furthermore, the info in Street Legends comes from Eliohann himself, and do you really want to trust everything a dragon (even a dragon e-ghost) tells you about themselves? Hell, even Plan 9 says later on in that same profile (once he realized that Eliohann gave him this info) that the dragon e-ghost had vetted everything.
Even if you take the Street Legends profile as 100% gospel, there are counter-indicators even within the profile that suggests that even if he did have a full-on psychotic break, he got better over time, especially after he got an upgraded datajack. And how would you check his records before and after the Crash? How many psych evals of a dragon do you think actually survived Jormungand? We have hearsay and conjecture, brought to us by a conspiracy theorist fed info by a dragon. I'd say a healthy degree of skepticism is in order.