Aims To identify the prevalence of pathological gambling (PG) in patients with Parkinson's disease (PD) from studies using comparable methodology to the best general population estimates. Additionally, to collate case-control based observations regarding the clinical characteristics of this phenomenon.

Methods MEDLINE, EMBASE and PyscInfo databases were searched for prospective prevalence studies which used systematic screening methods and interview based diagnosis using recognised diagnostic criteria for PD. The same search strategy was used to identify case-control studies examining the clinical characteristics of PG.

Results Five prospective studies were included in this review with a total of 1032 patients with PD. 3.2% of all patients fulfilled the diagnostic criteria for PG, compared to 0.43–1% in the general population based on North American surveys. The prevalence in men was 1% higher than in women, although this was not statistically significant. The prevalence of PG among patients on dopamine agonists was 5.7%. Younger age of PD onset, increased novelty seeking behaviours and personal/family history of alcohol misuse were all associated with PG. Psychiatric co-morbidities including other impulse control disorders were commonly reported, although no statistically significant associations have been found.

Conclusions Currently available evidence-based data suggest a high prevalence of PG among patients with PD. Dopamine agonist use was strongly associated with PG across all studies. Patients who develop PG present with specific clinical characteristics which are suggestive of underlying susceptibility factors.