Im sorry we cant tell you what to do for you, but I can tell you what I did when something similar happened to be. I contacted my treatment providers and spent sometime in a hospital to get stabilized.

this was not a bad thing for me because the fact that others were not taking control and letting one or me handle the situation actually showed improvement, healing and part of the integration process.

I tried so many times to get my therapist to tell me how to get the others to take control. she said it doesn't work that way. when the alters are not taking control no matter why, its because I have healed enough to handle things by myself with out dissociating every which way. she even asked when the suicidal / psychotic one was in control why others could not do so, and that alter said because they cant handle this I am the one that knows how to handle being psychotic and suicidal. that what I do.

while inpatient we talked about what possibly could be triggering the psychosis (hallucinations and delusions) adjusted my meds. and we discussed why I was suicidal what triggered that response, in other words why was the psychotic/ suicidal alter in control. that was when I was diagnosed Bipolar disorder. after I was stabile on antipsychotics / antidepressants for my bipolar disorder my brain naturally switched back to my normal awareness instead of the dissociated side of my personalities.

my suggestion if this continues to bother you contact yours or a mental health treatment provider who can help you get stabilized for what ever the trigger may be that has caused this psychotic/ suicidal alter to be in control (in other words their sense of agency and what in your life caused your brain to switch into being this alter)