Depressive traits in essential tremor: impact on disability, quality of life, and medication adherence.

BACKGROUND: There is growing study of the psychiatric features of essential tremor. Depressive symptoms occur in a considerable number of patients. Yet their impact, as a primary factor, has received almost no attention. We assessed whether, independent of tremor severity, patients with more depressive symptoms have more perceived tremor-related disability, lower tremor-related quality of life, and poorer compliance with tremor medication.
METHODS: On the basis of their Center for Epidemiological Studies Depression Scale score, we stratified 70 essential tremor patients into three groups: 41 with minimal depressive symptoms, 24 with moderate depressive symptoms, and five with severe depressive symptoms. Importantly, the three groups had similar tremor severity on neurological examination. We assessed self-reported tremor-related disability, tremor-related quality of life (Quality of Life in Essential Tremor) (QUEST) score, and medication compliance.
RESULTS: Cases with minimal depressive symptoms had the lowest QUEST scores (i.e., highest quality of life), cases with moderate depressive symptoms had intermediate scores, and those with severe depressive symptoms had the highest QUEST scores (i.e., lowest quality of life) (P < 0.001). Depressive symptoms were a stronger predictor of tremor-related quality of life than was the main motor feature of essential tremor (ET) itself (tremor). Self-reported medication compliance was lowest in cases with severe depressive symptoms and highest in cases with minimal depressive symptoms.
CONCLUSIONS: The physical disability caused by the tremor of ET has traditionally been regarded as the most important feature of the disease that causes distress, and it has received the most attention in the management of patients with this disease. Our data indicate that this may not be the case.