Communication is a huge difficulty in researching Deafness in psychiatry and in practically assessing and treating deaf patients. This paper aims to review the difficulties surrounding the assessment and treatment of deaf patients, using a review of the current literature on audio-visual hallucinations as an example. It will also include a summary of the published inquiry into the care and treatment of Daniel Joseph (a profoundly Deaf man), and a review of the Department of Health consultation document and NHS England responses to that inquiry as evidence of why these difficulties have relevance in everyday practice. In structuring the paper in this manner, the author hopes to review the current state of healthcare provided for Deaf individuals within psychiatry, and what still needs to be done.