Association of Progressive Supranuclear Palsy (PSP) with Psychosis and Hallucinations
Progressive Supranuclear Palsy (PSP) is not typically associated with psychosis and hallucinations, unlike other neurodegenerative disorders such as Parkinson's disease and Lewy body dementia. 1, 2, 3
Clinical Features and Differential Diagnosis
PSP is characterized by:
- Early postural instability and falls
- Vertical gaze abnormalities (particularly vertical saccade abnormalities)
- Poor response to levodopa therapy
- Axial rigidity
- Cognitive-behavioral changes 1, 2
Neuropsychiatric Symptoms in PSP vs. Other Disorders
PSP patients typically present with:
- Apathy
- Disinhibition
- Cognitive impairment
- Frontal lobe dysfunction 3
In contrast, hallucinations and psychosis are more commonly associated with:
- Parkinson's Disease (PD), especially after 10+ years of treatment
- Dementia with Lewy Bodies (DLB)
- Frontotemporal dementia with C9orf72 mutations 4, 5, 3
Evidence on Psychosis in PSP
Research comparing PSP and PD patients has found:
- PSP patients show significantly more apathy and disinhibition
- PD patients have higher frequency of hallucinations, delusions, and depression 3
- In a study of 19 PSP patients, psychiatric symptoms were generally mild, with depression and anxiety being more common than psychosis 6
- Sleep disturbances and hallucinations in PSP may be associated with increased mortality risk 7
Diagnostic Considerations
When evaluating a patient with parkinsonism and psychotic symptoms:
- Consider DLB if hallucinations occur early in the disease course
- Consider PD with psychosis if hallucinations develop after years of dopaminergic treatment
- Consider frontotemporal dementia with C9orf72 mutations if there are severe psychotic symptoms (delusions and hallucinations reported in 21-56% of cases) 1
- PSP is less likely if prominent psychotic features are present 1, 3
Clinical Implications
- The presence of psychosis or hallucinations in a patient with parkinsonism should prompt consideration of alternative diagnoses to PSP
- Diagnostic tests for PSP should include:
- Assessment of vertical saccade abnormalities
- MRI brain (looking for midbrain atrophy/"hummingbird sign")
- FDG-PET (hypometabolism in medial frontal and anterior cingulate cortices)
- DaTscan (decreased radiotracer uptake in striatum) 2
Management Considerations
- No disease-modifying treatments are currently available for PSP
- Patients typically have minimal response to medications
- If psychotic symptoms are present in a patient with suspected PSP, consider:
The absence of psychosis and hallucinations can be a useful clinical feature to help differentiate PSP from other parkinsonian syndromes, particularly PD and DLB, where these symptoms are more prevalent.