Depression disorder in patients with cerebellar damage: Awareness of the mood state.

Background: Although depressive symptoms are often reported to be comorbid with degenerative cerebellar diseases, the role of the cerebellum in depressive disorder needs to be elucidated. To address this aim, we investigated self-perception of the negative mood state in patients with cerebellar pathology and depressive symptoms.

Methods: Thirty-eight patients with cerebellar damage (10 with depressive symptoms - CB-DP and 28 with no depressive symptoms - CB-nDP), 11 subjects with depressive disorders without cerebellar damage (DP) and 29 healthy controls (CTs) were enrolled. A device for self-monitoring of the mood state (MoMo) and validated scales such as the Profile of Mood States questionnaire (POMS), the Self-Report Symptom Inventory-Revised (SCL-90-R) and the Hamilton Depression Rating Scale (HDRS) were used to evaluate depressive symptoms.

Results: Both CB-DP and DP patients showed higher scores than CTs on the POMS and SCL-90-R for depressive factors and on the HDRS. DP patients showed a lower frequency of 'good' mood and a higher frequency of 'bad' mood than CTs when using the MoMo device. However, although the two depressed populations showed comparable scores on these validated scales, CB-DP patients showed impaired self-awareness of the mood experience in 'the here and now', as evidenced by the absence of significant differences, compared with CTs, in the subjective mood evaluation performed with the MoMo device.

Limitations: The number of CB patients and inhomogeneity across MRI scans were study limitations.

Conclusion: Cerebellar dysfunction might slow the data integration necessary for mood state awareness, resulting in difficulty of depressed CB patients in explicitly recognizing their mood "in the here and now".