Table 1.
Patient characteristics
| ON | OFF | HC | Main effect ICD | Main effect MED | MED × ICD | |||
|---|---|---|---|---|---|---|---|---|
| PD ICD+ | PD ICD− | PD ICD+ | PD ICD− | |||||
| Number of participants, n | 36 | 96 | 12 | 46 | 60 | – | – | – |
| Age, years | 57.25 (10.2) | 61.08 (9.08) | 63.25 (7.07) | 60.46 (9.68) | 60 (9.61) | n.s. | n.s. | n.s. |
| Gender, female/male | 14/22 | 55/40 | 2/10 | 23/23 | 27/33 | ** | n.s. | n.s. |
| Depression (BDI) | 13.22 (8.01) | 8.52 (6.28) | 12.92 (6.82) | 7.39 (4.73) | 4.6 (3.51) | *** | n.s. | n.s. |
| ICD (QUIP-rs) | 26 (10.13) | 3.68 (4.27) | 23.08 (11.9) | 5.57 (5.07) | 21.98 (10.13) | *** | n.s. | n.s. |
| Anxiety (STAI:trait) | 42.06 (9.28) | 34.73 (9.91) | 42.75 (10.64) | 32.87 (7.97) | 33.76 (6.77) | *** | n.s. | n.s. |
| Disease severity (UPDRS:ON) | 28.56 (12.16) | 25.73 (11.02) | 32.36 (13.43) | 26.7 (13.62) | – | n.s. | n.s. | n.s. |
| Disease severity (UPDRS:OFF) | 32.28 (12.52) | 31.39 (11.82) | 38.08 (13.61) | 33.15 (13.45) | – | n.s. | n.s. | n.s. |
| LEDD | 700.64 (480.96) | 499.81 (237.45) | 535.06 (237.57) | 400.22 (267.79) | – | ** | * | n.s. |
| Dopamine receptor agonist use, yes/no | 20/16 | 28/68 | 6/5 | 15/24 | – | ** | n.s. | n.s. |
| Brixton | 14.33 (7.35) | 13.44 (6.17) | 13.92 (6.53) | 15.26 (5.9) | – | n.s. | n.s. | n.s. |
| Semantic fluency | 24.19 (6.26) | 25.89 (5.13) | 25.08 (6.37) | 25.72 (6.64) | – | n.s. | n.s. | n.s. |
| Symbols and digits | 33.81 (9.02) | 38.21 (7.83) | 35.58 (6.3) | 38.54 (5.4) | – | * | n.s. | n.s. |
| Months since diagnosis | 27.53 (18.33) | 24.37 (15.44) | 34.17 (17.96) | 32.52 (15.73) | – | n.s. | * | n.s. |
| Resting tremor | 1.08 (1.34) | 1.21 (1.67) | 0.83 (1.59) | 1.5 (2.13) | – | n.s. | n.s. | n.s. |
We subdivided the Parkinson’s disease (PD) population based on impulse control disorder (ICD) by using a clinical cut-off score for the Questionnaire for Impulsive-Compulsive Disorders in Parkinson’s disease Rating Scale (QUIP-rs). For a subdivision for depression, see Supplementary Table 5. To compare groups, we used a 2 × 2 ANOVA (Med × ICD-group). We found no interaction effects between medication (MED) and ICD-group. For gender and dopamine agonist use, we performed a chi-square test for both ICD versus non-ICD and ON versus OFF medication. *P < 0.05, **P < 0.01, ***P < 0.001. n.s. = not significant. BDI = Beck Depression Inventory; HC = healthy controls; LEDD = levodopa equivalent daily dose; UPDRS = Unified Parkinson’s disease Rating Scale; STAI = Anxiety Inventory for Adults.