The mental health care sector has been slow to adopt technology. However pressure on services from worsening mental health trends and a pressing need to develop innovative approaches to improved services has led to increased activity in this area. This paper discusses potential uses of ontologies in the development of interactive systems to support mental health interventions. Different aspects of the domain that may be modelled using ontologies are discussed and initial work in the development of an ontology based system is described. The paper also notes the importance and benefits of incorporating risk management into ontology based systems for this domain.