Abstract: The NeuroPsyGrid Project aims to build an ontology of psychosis that will be usable by practitioners and scientists across a range of different disciplines as a common and formalised knowledge framework. This paper provides a socio-technical perspective on the collaborative work involved in the development of such an ontology of psychosis. After introducing the context and nature of the project, we will elaborate on the challenges of such an undertaking, focussing on the process of ontology building and the socio-technical aspects of collaboration, including the meaningfulness of documents as boundary objects.