Self-report depressive symptoms are dissociated from tremor severity in essential tremor

Background: Depressive symptoms are associated with essential tremor (ET). However, the relationship between cognitive, functional, and motor measures with depressive symptoms in ET is not yet understood. Methods: The following measures were cross-sectionally assessed in a group of 223 subjects with ET: the Montreal Cognitive Assessment (MoCA) Scale, the Lawton Independent Activities of Daily Living (IADL) Scale, a neurologist assessment of tremor severity, and the Geriatric Depression Scale (GDS). Results: 20% (44) of the subjects met GDS criteria for depression (GDS ≥ 10). 43% (94) of the subjects showed at least some cognitive impairment (≤24 on the MoCA), and 15.3% (34) reported significant functional impairment (IADL score < 7). There was no significant association between GDS score and tremor scale score. The total GDS was negatively associated with the total MoCA score (Spearman's r = −0.15, p = 0.03). The total GDS was also negatively associated with the IADL score (Spearman's r = −0.19, p = 0.02), (logistic model odds ratio, OR = 4.91, p < 0.01). Over 60% of subjects who were depressed, per GDS cut-off score (≥10), were not receiving medical treatment for depression. Conclusions: There was a high point prevalence of depressive symptoms in subjects with ET. Self-report depressive symptoms are dissociated from tremor severity. Hence, these data do not support the hypothesis that depression in ET represents a psychological reaction to the tremor. There appears to be a clustering of cognitive, functional, and depressive symptoms in ET. Screening of depression in ET can improve our understanding and treatment of this disorder.