Neural mechanisms of delusions: towards a transnoslogical model
Final Report Abstract
Delusional beliefs are among the most striking symptoms of severe mental disorders such as schizophrenia. Despite their clinical relevance, the neural mechanisms underlying the emergence and maintenance of such beliefs remain poorly understood. A major challenge in this area of research is that delusions in schizophrenia typically co-occur with other symptoms, such as hallucinations or formal thought disorder, making their an investigation that is unbiased by other co-occurring symptoms very difficult. A promising alternative is the study of persistent delusional disorder (DD), which is characterized by long-lasting, monothematic delusions without prominent additional psychotic symptoms. DD is therefore considered an ideal “model disease” for targeted investigations of the neural basis of delusional experience. Within a collaborative project jointly funded by the DFG and the RFBR, two experienced research teams – the Cognitive Neuropsychiatry Group at Heidelberg University and a clinically well-experienced team at the First Moscow State Medical University – aimed to study patients with DD, individuals with schizophrenia and persistent delusions, and healthy controls. The project sought to combine clinical and neuropsychological assessments with state-ofthe-art multimodal magnetic resonance imaging to identify neural patterns associated with delusional states, particularly brain networks activated by specific delusional themes and those involved in impaired reality monitoring. A crucial component of the project was the planned use of a unique Russian patient database comprising over one hundred clinically well-characterized cases of DD. Internationally, a truly comparable repository of detailed clinical-psychopathological data on this rare disorder is not available. Integrating these datasets into a multimodal neuroimaging study with robust statistical power would have enabled the generation of one of the most comprehensive neurobiological datasets on delusional phenomena worldwide. However, the project was disrupted by the Russian invasion of Ukraine in February 2022. Continuing the study without the Russian collaborators proved nearly impossible, as similarly well-documented DD cases were not available, even in specialized European centers. Despite this setback, the project underscores the critical importance of international scientific collaboration in research on psychiatric disorders. Maintaining and expanding global scientific networks remains an urgent priority, above all in the interest of individuals suffering from severe mental illness.
Link to the final report
https://doi.org/10.4126/FRL01-006500754
Publications
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Abnormal subcortical volumes in psychotic patients with somatic delusions. Poster presented at the 22nd World Congress of Psychiatry (WPA), Bangkok, August 2022
Tomyshev A., Lebedeva I., Dmitrenko K., Yuzbashyan P., Dudina A., Bazhenova D., Romanov D., Wolf R.C. & Smulevich A.
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Cortical folding complexity is distinctively altered in schizophrenia and bipolar disorder. Schizophrenia Research, 241, 92-93.
Trevisan, Nicolò; Miola, Alessandro; Cattarinussi, Giulia; Kubera, Katharina M.; Hirjak, Dusan; Wolf, Robert Christian & Sambataro, Fabio
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Decreased axial diffusivity in psychotic patients with persecutory and somatic delusions. Poster presented at the 22nd World Congress of Psychiatry (WPA), Bangkok, August 2022
Tomyshev A., Lebedeva I., Yuzbashyan P., Dmitrenko K., Dudina A., Bazhenova D., Romanov D., Wolf R.C. & Smulevich A.
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Regional White Matter Lesion Load in Elderly Patients With Somatic vs. Non‐Somatic Delusional Disorder. Psychogeriatrics, 25(4).
Wolf, Robert Christian; Schmitgen, Mike M.; Otte, Marie‐Luise; Karner, Martin; Pycha, Roger; Kirchler, Erwin; Wolf, Nadine Donata & Huber, Markus
