Clinical correlates of apathy in patients recently diagnosed with Parkinson's disease: the ANIMO study

Objective: Little is known about apathy in the early stages of Parkinson's disease (PD). We determined the clinical correlates of apathy in a large representative sample of patients recently diagnosed with PD (ANIMO study).

Methods: PD patients, diagnosed within 2 years of inclusion, were recruited in 102 outpatient clinics situated in 82 populations throughout Spain. Apathy was quantified using the Lille Apathy Rating Scale (LARS). Clinical comparisons and correlations were performed using nonparametric tests. Regression analyses were used to test the association of clinical variables with apathy.

Results: We recruited 557 PD patients (60.3% men) with a mean age of 68.8 ± 9.7 years, and UPDRS motor score of 21.1 ± 10.8. Apathy only was diagnosed in 186 (33.4%), and apathy and depression in 215 patients (38.6%). Patients with higher comorbidity (OR = 1.10, 95% CI 1.01-1.20, p = 0.001), motor impairment (OR = 1.07, 95% CI 1.03-1.10, p < 0.0001), and lower education (OR = 2.16, 95% CI 1.21-3.85, p = 0.009) had higher odds of having apathy, in contrast to patients living in a rural environment (OR = 0.35, 95% CI 0.32-0.85, p = 0.01), and left predominant PD motor laterality (OR = 0.34, 95% CI 0.13-0.88, p = 0.01). LARS scores were significantly correlated with UPDRS motor scores (r(s) = 0.44, p < 0.001), predominantly with axial score (r(s) = 0.43, p < 0.001).

Conclusions: In PD, apathy is a very common and disabling nonmotor symptom separable from depression. Patients living in a rural environment, with lower comorbidity and motor impairment, higher education background, and left predominant PD motor laterality are at lower risk of suffering from apathy.