Impulsivity and compulsivity in drug-naïve patients with Parkinson's disease

Abnormal repetitive behaviors have been reported in Parkinson's disease (PD) during dopamine replacement therapy (DRT) and associated with individual predisposing features, including impulsivity. However, impulsivity and compulsive symptoms have never been explored in PD patients before initiation of DRT. We previously reported a 20% of impulse control disorders (ICD) in an Italian cohort.

103 consecutive newly diagnosed drug-naïve PD patients (means: age = 60.5 ± 9.2 years; duration = 15.4 ± 15.3 months) were screened for compulsive sexual behavior, compulsive buying, intermittent explosive disorder (Minnesota Impulsive Disorders Interview, MIDI), and pathological gambling (South Oaks Gambling Screen, SOGS). Barratt Impulsiveness Scale (BIS-11) and Maudsley Obsessional-Compulsive Questionnaire (MOCQ/R) assessed impulsivity, obsessive-compulsive symptoms, respectively. Depression (GDS-15) and general cognitive status were additionally assessed. We also compared ICDs frequency with our healthy controls.

17.5% of PD patients screened positive for at least one ICD at MIDI (17/103) and SOGS (1/103), though none had a disorder based on DSM-IV criteria. These frequencies were similar to healthy controls. There was a trend toward higher scores in BIS-11 attentive-impulsivity subscale (15.2 ± 4.8 vs. 18.7 ± 4.9; P = 0.007) and in MOCQ/R-Doubting subscale (0.67 ± 1.1 vs. 1.5 ± 1.2; P = 0.007) in PD with ICD. We also observed a positive correlation between GDS-15 and BIS-11.

Similar to our healthy control population, we found a significant proportion of early PD patients positive for ICDs before starting treatment. We also found a relationship between impulsivity and depression. A detailed behavioral assessment before starting dopaminergic therapy is recommended.