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

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.

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).

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.

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.