Diagnostics and treatment of impulse control disorders, psychosis and delirium: systemic review-based recommendations - guideline “Parkinson’s disease” of the German Society of Neurology
Authors: Witt Karsten , Levin Johannes , van Eimeren Thilo , Hasan Alkomiet , Ebersbach Georg ,   for the German Parkinson’s Guideline Group, Bähr Mathias , Becktepe Jos , Berg Daniela , Brockmann Kathrin , Buhmann Carsten , Ceballos-Baumann Andrés , Claßen Joseph , Deuschl Cornelius , Deuschl Günther , Dodel Richard , Ebersbach Georg , Eggers Carsten , van Eimeren Thilo , Fanciulli Alessandra , Fimm Bruno , Folkerts Ann-Kristin , Gausepohl Madeleine , Hasan Alkomiet , Hermann Wiebke , Hilker-Roggendorf Rüdiger , Höglinger Günter , Höllerhage Matthias , Hopfner Franziska , Jost Wolfgang , Kalbe Elke , Kassubek Jan , Klebe Stephan , Klein Christine , Klietz Martin , Köglsperger Thomas , Kühn Andrea , Krack Paul , Krismer Florian , Kuhlenbäumer Gregor , Levin Johannes , Liepelt-Scarfone Inga , Lingor Paul , Loewenbrück Kai , Löhle Matthias , Lorenzl Stefan , Maaß Sylvia , Maetzler Walter , Menzel Regina , Meyer Philipp T. , Mollenhauer Brit , Neumann Manuela , Odin Per , Outeiro Tiago , Pötter-Nerger Monika , Reese René , Reetz Kathrin , Rieß Olaf , Ruf Viktoria , Schneider Anja , Schrader Christoph , Schnitzler Alfons , Seppi Klaus , Sixel-Döring Friederike , Storch Alexander , Tönges Lars , Trenkwalder Claudia , van Eimeren Thilo , Walter Uwe , Wächter Tobias , Warnecke Tobias , Wegner Florian , Winkler Christian , Witt Karsten , Woitalla Dirk , Zeuner Kirsten , Bantel Martina , Witt Jonas L. 
Published: July 2024

Abstract
Background and objective
Impulse control disorders (ICD), psychosis and delirium are part of the spectrum of behavioural changes associated with Parkinson’s disease (PD). The diagnostic and therapeutic management of these rather complex neuropsychiatric conditions has been updated in the clinical guideline by the German Society of Neurology (DGN).

Methods
Recommendations are based on a systematic literature reviews, other relevant guidelines and expert opinion.

Results
Patients receiving dopamine agonists (DA) therapy should be informed about the symptoms and risks of an ICD and should be routinely screened for ICD symptoms. In the presence of an ICD, DA should be reduced or discontinued and psychotherapeutic treatment may be considered. Non-oral therapies (levodopa/carbidopa intestinal gel infusion or deep brain stimulation) may also be an option for appropriate candidates. Psychosis in PD often has a gradual onset. Cognitive and affective disorders, psychiatric and medical comorbidities as well as polypharmacy are risk factors for a psychosis. Non-pharmacological treatments should be implemented as soon as possible and anti-parkinsonian medications should be adjusted/reduced if feasible. For psychosis associated with PD, quetiapine or clozapine should be used on an as-needed basis and for as short a time as is necessary, with safety monitoring. Delirium in PD may be underdiagnosed due to an overlap with chronic neuropsychiatric features of PD. Although transient by definition, delirium in PD can lead to permanent cognitive decline, motor impairment and increased mortality. Management of delirium includes pharmacological and non-pharmacological interventions.

Conclusion
The updated guideline encompasses the evidence-based diagnostic, non-pharmacological and pharmacological management of ICD, psychosis and delirium in PD.