A 37-year-old woman was referred to a Center for Special Dentistry (CBT) because she could not be treated in home practice. A conversion disorder, or functional neurologic symptom disorder, was diagnosed five years ago. This refers to unplanned movements and symptoms that can’t be explained by a neurological or other somatic disorder. In this patient, it manifests itself in difficulty in swallowing and tolerating very little water or food in the mouth. The patient is afraid that the conversion disorder will not be taken seriously during the dental treatments. That is why the patient asked the CBT dentist to take this into account and teach her some tricks for the conversion disorder, so that she can eventually be treated again in the general dental practice. This case serves as an example to discuss the problems related to dental treatment of patients with a serious mental illness.