Does the Country Make a Difference in Impulse Control Disorders? A Systematic Review

Background: Impulse control disorders (ICDs) have an increased frequency in patients with Parkinson's disease (PD), mainly because of treatment with dopamine agonists (DA). Factors related with the country of origin (culture, economy, healthcare politics) may impact phenomenology. Objectives: To explore phenomenology of ICDs depending on the country. Methods: A systematic review following PRISMA guidelines was performed using Pubmed database. Articles published up to 2018 in which the prevalence of ICDs was analyzed were selected. Results: Thirty-two studies from 22 countries worldwide were included. The highest prevalence of ICDs in each continent was found in UK (59%), USA (39.1%) and India (31.6%). Frequency of ICDs was higher in those studies with lower mean age, higher proportion of males, whenever a screening instrument was used and whenever prescription of DAs was more common. Prevalence of ICDs was higher in Western countries compared to Asian countries (20.8% vs. 12.8%, P < 0.001) as it was the proportion of patients treated with DAs (66% vs. 48.2%, P < 0.001). Hypersexuality was the most common ICD overall (up to 23.8%). The highest frequencies of compulsive buying and eating were found in Western countries. Gambling was less commonly diagnosed, but prevalence was relevant Japan (14%). Conclusion: We observed a tendency towards a different ICD profile in different geographical areas, which may be attributable to socio-economical, cultural or political influences in the phenomenology of these disorders. Acknowledging these differences could help their early detection, which is critical for prognosis.