Here is a very simple model for the pragmatic therapy of schizophrenic psychosis. (I say 'simple', and it is, but the theories in terms of which it is cast are not at all simple. I shan't be spelling out these theories here, and will instead assume a ridiculously happy congruence between i) the reader's prior reading and philosophical prejudices and ii) my own.) It is built on a) an understanding of the nature of the core psychotic disturbance drawn from phenomenology and psychoanalysis, b) an understanding on the nature of the self drawn from existential phenomenology, and c) an understanding of the nature of effective therapeutic treatment drawn from the behavioural therapy known as ACT or acceptance and commitment therapy. I'm posting it because it seems fairly obvious, but I've not seen it articulated in just this way in the literature - probably because a) or b) and c) are not often drawn into close proximity, but also because there is much in the RFT background to ACT which is inimical to the philosophical spirit of existential phenomenological theorising about 'the self'.
a) A person 'with schizophrenia' suffers from a schizotaxic deficit. This constitutes a fragility in their capacity to hold themselves together - or, more accurately, a fragility in the capacity of their lived body to remain held together - in the context of (in particular) emotionally significant interpersonal encounters. The fundamental disturbance is accordingly a 'self disturbance'. The boundary between self and world or self and other - a boundary generated by the body schema in action - is always somewhat fragile, and then when stressed too greatly, becomes altered. The boundary between self and world, or self and other, starts to fall apart. From this basic self disturbance arises all the secondary symptoms such as delusions, hallucinations, passivity phenomena, etc.
b) Additional strain is placed on the smooth functioning of the body schema by powerful affects such as anger/anxiety. Psychotic terror at the dissolution of the self itself promotes further self-dissolution. There is however nothing that any of us can do, directly with the resources of the conscious mind, to reduce self-disturbance. Any thinking will occur 'on top of', grounded in, the self-disturbance. The kinds of hyper-reflexive retreats documented by Laing and Sass do not promote genuinely different ways of grounding the self. (Instead they are simply that: retreats from being, however much they are narcissistically dressed up as alternative realities.) The grounds of the self always remain inarticulate, background, non-reflective, aspects of bodily going-on-being which we can only promote obliquely.
c) Part of that oblique treatment will involve any exercises of whichever sort which can aid in the recalibration and stabilisation of the body schema. The kinds of bodywork promoted by Rohricht and Schoop may help here. However ACT surely has something else - and something important - to offer. Which is the idea of dropping control agendas with regards the occurrence of distressing mental events, and also the idea of promoting an acceptance of whatever comes into the mind (acceptance tempered by a distancing acknowledgement of that whatever's mental as opposed to real state). That much has already been said in the ACT on psychosis literature. But I'd like to propose a third piece of groundless trust which it would behove the therapist to promote - namely, a trust that the body schema will look after itself if one allow it to. If one can allow oneself to 'go with' (without 'buying') the psychotic experience. Take courage, re-engage with the lived environment, and do not hyper-reflexively try to create a psychic retreat or a rigidified way of being to 'manage' the psychotic experience.
The self in psychosis has weak foundations, but these foundations are, as for everyone, constantly enacted (the path that is layed down in walking) in the course of a meaningful life lived. Can the schizotaxic patient allow that path to lay itself down, to not try to lay it down and thereby inadvertently build castles in the air which constantly threaten to crash down to earth, to instead take themselves on walks through familiar and comfortable terrains and tolerate the rough ground?