Severe Somatic Hallucination Induced by Antiparkinson Drugs: A Case of an Elderly Patient Misdiagnosed with Parkinson’s Disease

Hallucinations are common as psychiatric symptoms in the treatment course of Parkinson’s disease (PD). The majority of them are considered to be associated with both antiparkinson drugs and the disease process itself. Visual hallucination (VH) and delusion of persecution are very common, while olfactory or somatic hallucination (SH) is less common. The author reports an elderly female patient who exhibited severe SH accompanied by involuntary movement that disappeared after the discontinuation of all antiparkinson drugs. She had been misdiagnosed with PD. The present case might reveal “genuine” psychiatric side-effects induced by increasing numbers and doses of antiparkinson drugs. Interestingly, VH, which PD patients most often develop, was not observed here at all. It might be SH, not VH, that is more strongly associated with antipakinson drugs. SH in this case consisted of two types of abnormalities in the sense of body balance and of being touched, and both have been rarely reported in other diseases. This case suggests that SH, although not very common in PD, may be a unique and noticeable symptom as the psychosis induced by antiparkinson drugs.