Obsessive-Compulsive Behavior in PSP

These Japanese researchers studied the “obsessive-compulsive symptoms” (OCS) in PSP. The purpose of their study “is to investigate OCS in PSP in terms of the incidence, clinical features, associations with demography, cognition, and structural and functional imaging, and to propose possible mechanisms behind this specific behavioral psychological symptom of dementia of PSP.”

In the 74 patients studied, 24% had OCS, which the authors consider a “relatively high incidence.” “They were obsessed with daily trifles and physical symptoms among other things.” The authors conclude: “OCS are frequent but under-recognized behavioral and psychological symptoms of dementia in PSP.”

I wonder if other researchers view OCS as a dementia symptom?

You might be wondering about OCD, obsessive compulsive disorder. The authors describe OCD as “another psychiatric disorder that is defined as recurrent and persistent thoughts that are experienced as intrusive and inappropriate and cause marked anxiety or distress.” In the full article, the authors say:

“Although similar, we found some differences between OCD and OCS. Obsessive ideas and compulsive behaviors appear unreasonable and excessive to caregivers and medical staff more than the patient. PSP patients with OCS are more likely to react to obsessions autonomously or in an environmentally-dependent fashion rather than being forced to cope with these unreasonable ideas and harassed with anxiety or conflicts. … Unawareness or anosognosia for these symptoms clearly delineates them from OCD.”

The authors also point out that OCS is different from the delusions or hallucinations that are part of Dementia with Lewy Bodies.

The abstract is copied below.


Dementia & Geriatric Cognitive Disorders. 2010 Aug 26;30(2):179-188. [Epub ahead of print]

Obsessive-Compulsive Behavior as a Symptom of Dementia in Progressive Supranuclear Palsy.

Fukui T, Lee E, Hosoda H, Okita K.
Department of Internal Medicine, Division of Neurology, Showa University Northern Yokohama Hospital, Yokohama, Japan.

Aims: To describe obsessive-compulsive symptoms (OCS) as under-recognized behavioral and psychological symptoms of dementia of progressive supranuclear palsy (PSP) and to discuss possible mechanisms based on MRI and SPECT findings.

Methods: We studied 74 PSP patients. OCS are defined as persistent and unreasonable, but non-delusional/hallucinatory, ideas and behaviors. Demography, cognition, the widths of middle cerebellar peduncles (MCP) and the inter-caudate distances (ICD), both corrected by the intracranial size (MCP and ICD ratios), and changes on voxel-based SPECT were compared between the subgroups with and without OCS. Finally, the predicative power of various factors to OCS was investigated.

Results: We observed OCS in 18 patients (24%). They were obsessed with daily trifles and physical symptoms among other things. OCS was not associated with demography or cognitive levels.

OCS-positive patients had significantly smaller MCP and ICD ratios and showed marked uptake decreases in the orbitofrontal cortex, caudate and thalamus. Relative uptake increases in the cerebellum, specifically the tonsils, were milder in OCS-positive than -negative patients. A smaller right MCP, a smaller ICD ratio and lower uptake increases in the right cerebellar were the significant predictors of OCS.

Conclusions: OCS are frequent but under-recognized behavioral and psychological symptoms of dementia in PSP. Dysfunction of the fronto-caudate-thalamus-cerebellum circuit may be involved.

PubMed ID#: 20798538 (see pubmed.gov for abstract only)