LP, we often experience that kind of stuff too. Like another internal one is there with you, and its hard to figure out what is what. The opposite is weird too - when another one that you usually have coconsciousness with retreats and disappears for a while... and you suddenly feel very, very alone!

LITW, our coconsciousness comes and goes too. For several years I would have even said that I had integrated with a bunch of front alters. Recent events proved that wrong, though, and we have separated again, with some now in a lesser state of coconsciousness and some behind walls again. We have also experienced 'being dissociated from our multiplicity' several times, for long periods of time. It is like being in a horror movie to 'wake up' again only to see we are still in the same situation.
My theory is it has to do with stress, like you said, and a lack of external safety.

In therapy situations I often experience interference from internal ones that have not fully taken over but instead exert great influence over me. Sometimes I experience this as 'thought insertion' or 'thought deletion' - both schneiderian first rank symptoms but dissociation related rather than psychosis related.

AL, I know you've said before that reality testing remains intact in DID, but I am still confused by that and am not sure what you mean. My own experience is that reality testing doesn't always remain intact at all, yet I know I am not in any way psychotic. What I mean is that some child alters believe they are children and some are emotionally stuck in abuse scenarios. Some parts believe they are male (obviously they are not). A couple believe they are animals (obviously not true either!) Does that mean their (my?) reality testing is not intact?