In the present study, the serum CRP levels in amphetamine addicts (6.54 ± 0.63 ng/ml) and PD patients (5.46 ± 0.41 ng/ml) were significantly higher compared to that in controls (3.75 ± 0.32 ng/ml) (p = 0.0001 and p = 0.012, respectively). Here, CRP is linked to Parkinson disease.