The relationship between temperament and depression in Parkinson's disease patients under dopaminergic treatment

The risk factors for depressive symptoms in patients with Parkinson's disease (PD) under dopaminergic drug treatment are unclear. In this study, we examined whether some temperament traits are related to the presence of comorbid depression in PD patients, independent of the characteristics of illness and drug treatment.

The participants in this study were 74 patients with idiopathic PD who were already treated with stable doses of levodopa or dopamine agonists. Depressive (n = 20) and non-depressive (n = 52) PD patients were assessed by means of the Unified Parkinson's Disease Rating Scale, Beck Depression Inventory, and Temperament Evaluation of Memphis, Pisa, Paris and San Diego Auto-questionnaire. The doses of levodopa and dopamine agonists were converted into levodopa equivalent daily dose.

The duration of treatment in the depressive group was significantly longer than in the non-depressive group (P = 0.03). The depressive patients had significantly higher scores on the Unified Parkinson's Disease Rating Scale than the non-depressive patients. Depressive (P < 0.0001), cyclothymic (P < 0.0001), anxious (P < 0.0001), and irritable (P = 0.02) temperament scores were significantly higher in depressive than in non-depressive patients. Hyperthymia scores were significantly higher in non-depressive patients than in depressive patients (P = 0.01). Logistic regression analysis revealed that depressive temperament traits (P = 0.03) significantly predicted the diagnosis of depression. In contrast, hyperthymic temperament seemed to be associated with the absence of depression (P = 0.006).

Our results indicated that the severity of PD and duration of dopaminergic treatment were not predictive of the development of depression in PD patients. Depressive temperament strongly predicted the development of depression in our sample. Hyperthymic temperament seemed to be associated with patients without depression. We suggest that depressive temperament traits seem to be related to depression, while hyperthymic temperament may have a protective role in the risk of depression in PD patients.