COMT and Parkinson disease: Finally, compulsive medication use was significantly related to younger age at PD onset (ρs = −0.25; p < 0.035), L-dopa mg/die assumption (ρs = 0.25; p < 0.035), COMT-inhibitors (ρs = 0.32; p = 0.006), and total LEDDs (ρs = 0.34; p = 0.003).