Progressive supranuclear palsy misdiagnosed as depression and catatonic schizophrenia

Introduction: Motor deficits of progressive supranuclear palsy (PSP) are well known, but psychiatric symptoms are less recognized. While PSP is routinely considered in the differential diagnosis of Parkinsonian disorders, it usually is not considered in the differential diagnosis of psychiatric disorders.

Report of a case: A 53-year old man was externally diagnosed and treated for major depression and catatonic schizophrenia in several psychiatric hospitals for 28 months before admission to our psychiatric service. Various antidepressive treatments and antipsychotic treatment with risperidone did not show any improvement. Deterioration in cognition and mnestic function was suspected and the patient was transferred to our hospital for further assessment of a neurodegenerative dementia. Dysarthric speech and shuffling gait had been noticed but were attributed to side effects of risperidone. The neurological examination revealed vertical gaze palsy, pseudobulbar palsy, bradykinesia, greater axial than limb rigidity, postural instability with falls backwards in the history, inexhaustible glabellar and bilateral palmomental reflexes, frontal lobe signs (grasping and perseveration), but no tremor. There was no response to levodopa treatment. PSP was suspected. MRI, FDG-PET, and CSF (including beta-amyloid and tau protein) were normal, presenting no evidence for other neurodegenerative diseases. DAT-scan was normal, making Parkinson's disease unlikely. An IBZM-SPECT showed no significant changes thus neither confirming nor eliminating PSP. The clinical diagnosis of probable PSP was made. Antipsychotic treatment was changed to clozapine resulting in a sustained improvement of the catatonic pathology. Antidepressive treatment with escitalopram resulted in improved mood and drive.

Conclusions: Prominent psychiatric symptoms of early PSP may lead to a misdiagnosis complicating treatment and consultation of patients. PSP should be considered as a differential diagnosis of organic diseases causing katatonia and depression. Clozapine was effective in ameliorating the catatonic symptoms without deteriorating the dopaminergic dysbalance thought to cause motor symptoms in PSP. Co-morbidity of schizophrenia and PSP was reported previously and may indicate overlapping deficiencies of dopaminergic pathways in both conditions.