One of the more unusual uses of virtual reality is to study -- and even treat -- schizophrenia. You might be thinking that putting a schizophrenic person into an imaginary world is a terrible idea; it certainly sounds a bit counterintuitive. But remember that one of the biggest benefits of virtual reality is the safety of the environment. In this case, that applies not just to the patient, but to the people around him or her.
First off, schizophrenia can be measured in a virtual environment in a way that wouldn't work in the real world. Like a lot of mental illnesses, schizophrenia must be understood in social context. (Interacting in the real world is where mental illness starts to present itself, after all.) But it's not safe (or ethical) to put a schizophrenic person in an atmosphere that might cause them anxiety or where they might react dangerously. So researchers developed virtual reality tools to help. One is a program that imitates a subway ride; they can monitor patient symptoms to their responses to neutral avatars. (For instance, if a patient is convinced one of the virtual characters is talking about him or her, it would indicate a high level of paranoia to the clinician.) Treatment could also be explored. Clinicians could demonstrate how medication affects a patient's experience by introducing them to the same situation off and on meds, giving them examples of how treatment is positive.