Abstract

Delusional Misidentification Syndrome in Parkinsons Disease: A Systematic Review and New Approach to our Neurobiological Understanding

Author(s): James Mitchell, Sheliza Samnani, George Tadros

Capgras syndrome (CS) describes a delusional misidentification syndrome whereby a person’s loved one or property has been replaced by an imposter. It has commonly been reported in neurodegenerative diseases, but is less frequently reported in Parkinson’s disease (PD). We report the case of a 77 year old male with PD, cognitive impairment and increasing visual hallucinations and symptoms of anxiety and depression. He developed CS reporting that his wife was intermittently replaced by an imposter. Whilst symptoms of anxiety and depression responded well to antidepressant treatment, and visual hallucinations responded to rivastigmine, the delusional belief still persists. We perform systematic literature review and identify 18 additional cases of CS in PD. The majority of cases identified describe concomitant cognitive impairment as well as visual hallucinations. Varied pharmacological strategies employed in treating the described patients make it difficult to distinguish the effect of any particular pharmacological intervention of underlying neurotransmitter disturbance underlying the delusion in PD. It is possible that a novel neurobiological mechanism is at play in these patients, and elucidating this further may increase our understanding of the neurobiological basis of the delusional misidentification syndrome.