Did Inubushi Keiko really have DID?

How long did she have DID?
During Satoru’s route, the Inubushi we see is almost entirely Inubushi Keiko’s true personality. However, if you think about her personality on its own, some things don’t quite line up. Inubushi is supposed to have DID, but we never really see any signs of that. In Satoru’s route, Inubushi’s memories seem to be continuous, and not fragmented between personalities.

Did Inubushi Keiko have DID? Yes, most likely. The symptoms of DID were still present while she was under hypnosis, so there’s probably no doubt about that. But the question is, did she have DID in the year 2012? The answer is probably no. Since she seems to have all her memories, they were probably all consolidated into a single personality.

Unstable mind
In Kokoro’s route, Inubushi displays personalities similar to the ones listed below:

C: An innocent 6-year-old boy who cries a lot
D: A gloomy young man that injures himself sometimes
F: A seductive woman in her late 20s
H: A quiet, introverted girl with a kind personality
J: A murderous personality. Prone to destructive and sadistic behavior.

For example…
– Playing Kagome Kagome with Yuni
– Asking if you would want to cut someone with a knife or be cut yourself
– Seducing Satoru when he came to her room
– Letting Utsumi tend to the wound on her back
– Killing a mouse with no hesitation

As you can see, traces of her different personalities still remain. Though they may all be part of one personality now, she still remains mentally unstable.

What does her instability mean?
If she’s so unstable, perhaps that means the merging of her personalities is something that happened only recently. Her instability may also indicate that they were merged somewhat forcibly. There’s also the fact that she wasn’t familiar with the name Inubushi and didn’t know about Satoru (Blondie), which would be hard to believe for someone who was living at SPHIA. This may have just been a practical joke on her part or another sign of instability, but there’s another possibility. Perhaps she recently experienced memory loss…

What recent event could have caused her personalities to merge and caused her to lose some of her memory?