The automated delivery of psychological treatment using virtual reality (VR) has the potential to revolutionise patient access to evidence-based care. VR creates immersive, interactive computer simulations, which elicit responses similar to the real world. VR simulations provide an ideal opportunity for the experimentation and experiential learning that are key to successful cognitive therapy. If automated, and using the latest consumer kit, VR treatment can substantially scale-up the delivery of psychological therapy. However, the successful application of automated VR to mental health difficulties requires precise treatment targets linked to the right psychological theory and techniques. This paper describes the process of development of an automated VR cognitive therapy targeting anxious avoidance of everyday social situations by patients with psychosis. In the gameChange project, a person-centered design process was used involving people with lived experience of psychosis, clinical psychologists, designers, and software developers. The six-session gameChange VR therapy consists of six everyday scenarios: a street, a bus, a café, a pub, a doctor's waiting room, and a shop. Each scenario has five levels of difficulty. Every level provides an opportunity to test out fearful cognitions while limiting the use of safety-seeking behaviours, allowing patients to build confidence in their ability to cope. Learning is facilitated by a virtual coach and therapeutic gaming elements are included. Data from user testing indicates that the gameChange VR therapy is easy to use and engaging. The clinical effectiveness of gameChange VR therapy is now being tested in a randomised controlled trial with several hundred patients with psychosis.