A previously healthy 8-year-old girl began to experience nightmares, soon followed by sleeplessness and perceptual abnormalities including visual hallucinations. She also complained that she had been attacked and possibly assaulted sexually. Physical investigations were considered to have provided no relevant abnormality and psychiatric enquiries were begun directed towards possible sexual abuse. However, the child's mental and physical state continued to deteriorate and evidence of a progressive organic process was then obtained from past school reports, review of the initial EEG findings and further EEG investigations. The latter in particular indicated a diagnosis of SSPE which was confirmed immunologically. Treatment was ineffective and the child died 7 months after the onset of the illness. The details of the psychological changes at the onset of SSPE are ill-defined. This case illustrates that they can include psychotic phenomena but also that the basic nature of the disorder may be misconstrued as psychological depending on the circumstances.