Yes, in dissociative identity disorder (DID), also previously known as multiple personality disorder, it is common for different alters (alternate identities or personalities) to have varying degrees of awareness about each other. The way alters interact and communicate with one another can differ significantly from one individual to another. This is a complex and intricate aspect of DID that varies from case to case.
In some cases, alters may be fully aware of the existence of other alters, their names, roles, and characteristics. These alters may be able to communicate with each other directly or indirectly, either through internal communication (inside the person's mind) or through external means, such as through writing or drawing.
On the other hand, some alters may have limited awareness or no awareness of the existence of other alters. They might experience memory gaps or have no recollection of the time when other alters are in control. This lack of awareness is known as "amnesia barriers" and serves as a way to compartmentalize traumatic memories and experiences.
The level of awareness and communication between alters can fluctuate and change over time. Some individuals with DID may work towards improving communication and co-consciousness between their alters during therapy, while others might maintain a more separate and disconnected experience.
It's important to understand that DID is a complex and controversial disorder, and research and understanding of it are still evolving. The experiences of individuals with DID can vary widely, and the way alters interact is just one aspect of the disorder. If you or someone you know is experiencing symptoms of DID or any mental health concerns, it's crucial to seek help from a qualified mental health professional for an accurate diagnosis and appropriate support.