David Yeung said this quote

Among DID individuals, the sharing of conscious awareness between alters exists in varying degrees. I have seen cases where there has appeared to be no amnestic barriers between individual alters, where the host and alters appeared to be fully cognizant of each other. On the other hand, I have seen cases where the host was absolutely unaware of any alters despite clear evidence of their presence. In those cases, while the host was not aware of the alters, there were alters with an awareness of the host as well as having some limited awareness of at least a few other alters. So, according to my experience, there is a spectrum of shared consciousness in DID patients. From a therapeutic point of view, while treatment of patients without amnestic barriers differs in some ways from treatment of those with such barriers, the fundamental goal of therapy is the same: to support the healing of the early childhood trauma that gave rise to the dissociation and its attendant alters.Good DID therapy involves promoting co­-consciousness. With co-­consciousness, it is possible to begin teaching the patient’s system the value of cooperation among the alters. Enjoin them to emulate the spirit of a champion football team, with each member utilizing their full potential and working together to achieve a common goal.Returning to the patients that seemed to lack amnestic barriers, it is important to understand that such co-consciousness did not mean that the host and alters were well-­coordinated or living in harmony. If they were all in harmony, there would be no “dis­ease.” There would be little likelihood of a need or even desire for psychiatric intervention. It is when there is conflict between the host and/or among alters that treatment is needed.