Depressive state is a common complication in of SCA3. One study found that approximately 33.5% of SCA3 patients had depressive state [3]. However, to the best of our knowledge, cases of severe depressive state with unique psychotic features (i.e., cenesthopathy) in patients with SCA3 have not been described [1].
In a literature search on PubMed, we identified two studies involving patients with spinocerebellar ataxia presenting with psychotic symptoms [1] [7]. A case series by Turk et al. [7] identified patients with spinocerebellar ataxia who presented with delusions, paranoia, and auditory hallucinations. A previous study involving 112 patients with spinocerebellar ataxia found that only 5 patients had psychotic symptoms [1]. The mean age of SCA3 patients with psychotic symptoms was 68.4 ± 13.6 years old [1]. A recent report described a case of SCA3 with delusion and paranoia in a 30-year-old woman [7]. These findings suggest that this is the first case of SCA3 presenting with cenesthopathy in a young Japanese patient.
Schmahmann et al. [4] described cases of CCAS characterized by executive dysfunction, visuospatial impairment, language dysfunction, emotional disorders, and illogical psychotic thoughts in patients with cerebellar diseases. This suggests the possibility for the presence of neural connections among the cerebellum, non-motor cortical areas, and subcortical areas associated with cognitive and emotional processing [8]. Similar to our case, the SPECT results of a previous study showed that SCA3 patients had significantly lower regional blood flow in the bilateral cerebellum and vermis, compared with healthy subjects [1]. However, no significant differences in terms of regional cerebral blood flow were found between patients with psychotic symptoms and patients without psychotic symptoms [1]. However, the authors noted that their subjects were relatively old and had atrophy of the basal ganglia.
In our case, the patient was young with no obvious non-cerebellar abnormalities on CT or SPECT, ruling out age-related neurodegeneration as an etiology of psychotic symptoms. Moreover, another study implicates psychotic symptoms as an additional non-motor symptom in patients with ataxia due to the connections between the cerebellum and brainstem [4]. This is consistent with our findings of brainstem atrophy.
Cenesthopathy is strongly associated with schizophrenia [5]. While the link between schizophrenia and cerebellar dysfunction has been noted [6], the role of the cerebellum and brainstem in the pathogenesis of psychotic symptoms (e.g., cenesthopathy and delusions) must be studied further.
Despite the results of our study, there are several limitations identified. First, some patients with major depressive disorder have cenesthopathies [9]. Second, we did not perform dopamine transporter scans or other tests to assess the degeneration of the basal ganglia. Third, as he was bedridden, cenesthopathy characterized by a feeling that his body was attached to the bed could be understood to some extent.
We encountered a case of severe depressive state with psychotic features (i.e., cenesthopathy and delusion) in a 43-year-old man with SCA3. This study highlights the possibility for patients with SCA3 to present with severe depressive state and unique psychotic symptoms, even in younger patients where age-related neurodegeneration is unlikely. This suggests the complex role of the cerebellum in terms of emotional, perceptual, and psychiatric function, which may explain the underlying mechanism of psychiatric symptoms in these patients.