Preliminary evaluation of the DDS-PC inventory: a new tool to assess impulsive-compulsive behaviours associated to dopamine replacement therapy in Parkinson's disease.

Dopaminergic medications could increase the occurrence of a set of dysregulated behaviours in Parkinson's disease (PD), including reward-seeking behaviours (pathological gambling, hypersexuality, compulsive shopping, binge eating, reckless driving), punding and compulsive medication use. We report a preliminary evaluation of a questionnaire to assess the presence of these impulsive-compulsive behaviours associated to dopamine replacement therapy in PD. We screened 38 patients and their caregivers, comparing dopamine dysregulation syndrome (DDS) patients and non-DDS patients. The questionnaire was well accepted and demonstrated a preliminary good discriminant validity (p = 0.000). In addition, clinically relevant dysregulated condition is associated with a younger age (p = 0.006), younger age at disease onset (p = 0.001), levodopa-equivalent daily dose (p = 0.029), UPDRS III (p = 0.021), increased global psychopathology (interpersonal sensitivity and psychoticism), and differences in our inventory (p = 0.000). These preliminary results suggest that the DDS-PC inventory could help to identify patients experiencing impulsive-compulsive behaviours associated to DDS.

The thrill of reckless driving in patients with Parkinson's disease: an additional behavioural phenomenon in dopamine dysregulation syndrome?

We report two male patients with Parkinson's disease who developed compulsive risk-seeking driving behaviour as a result of self-administering high doses of L-dopa despite an adequate therapeutic response at lower doses. When L-dopa reduction was feasible, it resulted in cessation of unsafe driving. We believe that this impairment in driving performance, due to deliberate overuse of dopaminergic medication, should be included as a new behavioural phenomenon in dopamine dysregulation syndrome.

Prevalence of pathological gambling in patients with Parkinson's disease.

Pathological gambling (PG) is a psychiatric disorder characterized by loss of control of gambling, which has repercussions on family, personal, and professional life. Several recent studies have reported the relationship between PG and the treatment of Parkinson's disease (PD), but no prevalence study has yet been conducted to investigate this correlation. The purpose of this study was to evaluate the prevalence of PG in Italian patients with PD on dopamine replacement therapy. The prevalence of PG in a PD sample (n = 98) and in an age- and sex-matched control group (n = 392) was obtained. The prevalence of PG results significantly higher (P = 0.00001) in PD patients than in control subjects (6.1% vs. 0.25%). Our results emphasize that PG in patients with idiopathic PD on dopamine replacement therapy is an emergent comorbidity, but probably at present the condition is not properly diagnosed because it is mostly unknown.