New variant Creutzfeldt–Jakob disease is a novel prion disease of humans that may be causally linked to bovine spongiform encephalopathy. Psychiatric symptoms occur in the early stages of the illness and may be difficult to distinguish from the symptoms of more common psychiatric disorders. Cases of new variant Creutzfeldt–Jakob disease are identified through the national surveillance system. Information on psychiatric features has been obtained by review of case notes and, in the majority of cases, by interview of relatives by a member of the surveillance staff.

Thirty-five cases of new variant Creutzfeldt–Jakob disease have been identified in the UK and detailed information on the clinical features and investigations is currently available in 33 of these cases. All but one of the cases exhibited prominent early psychiatric symptomatology, but the diagnosis of an underlying neurological disease was not possible in the majority of cases until the development of neurological symptoms and signs. Early indications of an underlying neurological disorder included cognitive impairment, persistent sensory symptoms or limb pain and, in a minority, gait imbalance, dysarthria or visual symptoms. Limited evidence suggests that investigations such as electroencephalogram or brain imaging are unlikely to provde useful diagnostic information during the ‘psychiatric’ phase of the illness.

The early recognition of an underlying neurological disorder may be impossible in the early psychiatric phase of new variant Creutzfeldt–Jakob disease, but the suspicion of this diagnosis may be raised by the occurrence of associated neurological symptoms. The development of early diagnostic markers is an important objective.