To the Editor: Dr. Stone and colleagues make an excellent point: there can be a reluctance among psychiatrists to make the diagnosis of conversion disorder for fear the patient will develop a neurological disease that better explains the presentation of the illness. Dr. Stone and colleagues express concern that the case conference might reinforce an idea that development of a neurological disease in patients with a presentation most consistent with conversion initially is a common occurrence.

The case presentation was directed toward demonstrating how difficult it can be to establish a diagnosis of a neurological disease before there is a signature sign and how illness-related behavior, and interpretations of secondary gain, may sadly confound the clinician. It is helpful that a CSF assay for the 14-3-3 protein is now available, making a diagnosis of Creutzfeld-Jacob disease more straightforward in patients with otherwise ambiguous symptoms. In the case presented, there were no T₂-weighted hyperintensities in the basal ganglia or elsewhere on the MRI of the patient’s head. Furthermore, at that time, diffusion-weighted scans were not available, although they appear to be a relatively sensitive marker for Creutzfeld-Jacob disease (1). Fortunately, other individuals with conversion disorder whom we have seen on our unit had an illness that was far clearer in presentation and responded to treatment.

It was not our intention to generalize the experience with this case conference in a way that would prevent a reasonable diagnosis of conversion in a patient with medically unexplained symptoms. However, a cautionary note is inherent in the history of the case we presented. It is expected that any diagnosis made on the basis of an apparent exclusion of other causes, as is the case with conversion disorder, be held with some degree of suspended disbelief. Clinical vigilance, as we noted, is essential.