As Phil says in his 'Critical Psychiatry in The UK: A Personal View':-
Postpsychiatry started life as a series of short articles in Open Mind magazine [see reprints] from 1997 – 2001 .... This was followed by an article in the British Medical Journal Education and Debate section (Bracken & Thomas, 2001), and a book of the same name four years later in Oxford University Press’s series on philosophy and psychiatry (Bracken & Thomas, 2005).Postpsychiatry sees psychiatry as a creation of the Enlightenment and a modernist enterprise. The book starts with a reference to Foucault's Madness and Civilisation. Foucault viewed the Enlightenment as oppressive and saw the 'great confinement' in the 17th and 18th centuries as, in Pat and Phil's words, "a massive European move towards the social exclusion of 'unreason'" (p. 91). Pat and Phil note that Foucault moved away from an understanding of power as something negative. As they also say, "in the 20th century, psychiatry became something bigger than simply the governing power of the asylum" (p. 93).
They, therefore, view postmodernism as "an addition to, rather than a rejection of, previous critical positions" and insist that it is "not a flight to mindless relativism" (p. 95). Just to be clear, they say that "Foucault did not get everything right" (p.189). They, therefore, want to also follow Heidegger and Wittgenstein with a hermeneutical perspective. In the book, they look at what they call the narrative turn in medicine and psychiatry. Overall, they are not proposing "some sort of postmodern canon" (p.189).
Postpsychiatry is, therefore, not arguing for a strong form of social constructivism. My main problem with postpsychiatry is its historical narrative, maybe because it starts from Foucault. I have always tended to emphasise that there has always been a critical perspective within psychiatry (eg. see previous post), since the origins of modern psychiatry, which I would tend to date from state intervention in the asylum, rather than the 'great confinement'. The development of pathology in medicine from the beginning of the nineteenth century and the application of the anatomoclinical method led to psychiatry not completely fitting with an organic understanding of illness and, for example, produced the idea of functional psychosis (see another of my book chapters).
Although Pat and Phil mention the Enlightenment, they don't talk about Romanticism, which, in a way, was a reaction against the norms of the Enlightenment. I have highlighted the work of Ernst von Feuchtersleben in this respect (see eg. another previous post) and he used the critical philosophy of Immanuel Kant to argue against a materialistic understanding of mental illness. Similarly, modernism wasn't the only perspective at the turn of the twentieth century and, as I have said, Pat and Phil themselves mention hermeneutics. Personally, I have emphasised the pragmatic perspective of Adolf Meyer (eg. see another previous post), which, at least in theory, focused on the limitations of psychiatric practice (see eg. my article).
Postpsychiatry may be the best known form of critical psychiatry and is central to critical psychiatry's understanding of its own nature.