Obsessive-Compulsive Symptoms in Dementia: Scoping Review of Pathological Changes

Objective: To review the literature on the neurobiological mechanisms of obsessive-compulsive symptoms (OCS) in people with dementia.

Data Sources: MEDLINE/PubMed, CENTRAL, and PsycNet databases were searched from inception to March 2023.

Study Selection: Original studies of any methodology with newly published data on the neurobiological underpinnings of OCS in patients with dementia, regardless of patient age or comorbidity and publication year, were included. The following search terms were used: (Obses* OR compul* OR OCD) AND (cognitive de* OR cognitive dysfunction OR cognitive disfunction OR dementia).

Data Extraction: Individual study data were extracted onto a piloted extractions sheet.

Results: Patients with dementia and OCS were reported to have atrophy and hypoperfusion of frontal, temporal, striatal, and limbic structures. Serotonergic agents may be efficacious in reducing OCS. One randomized controlled trial of paroxetine in behavioral symptoms of dementia did not show efficacy. Evidence of dopaminergic dysfunction is too sparse to draw conclusions. Microglia dysfunction mediates obsessive-compulsive-like symptoms. Mutations of microtubule-associated protein τ may increase the risk of OCS. Cognitive self-consciousness and obsessive-compulsive-related cognitions may mediate OCS in old age. Dysfunction of the processing of one class of stimuli may increase the salience of other classes of stimuli, leading to OCS.

Conclusions: Frontal lobe hypometabolism and temporal lobe atrophy and hypometabolism are unexpected given previous research in obsessive compulsive disorder. Serotonergic agents have encouraging efficacy in case reports but require more specific research.

Prim Care Companion CNS Disord 2024;26(3):23r03689.

Author affiliations are listed at the end of this article.