Identifying PD patients vulnerable to dopamine dysregulation syndrome

A study has identified a number of predisposing factors to compulsive dopaminergic drug use in Parkinson's disease that may help early identification of vulnerable patients.Researchers in the United Kingdom compared the clinical features, personality traits and drug-taking histories of a group of Parkinson's disease patients with dopamine dysregulation syndrome (n=25) to a representative sample of patients without the syndrome (n=100). They found that patients with the syndrome had a younger age at disease onset, higher dopaminergic drug intake, greater past experimental drug use, more depressive symptoms and greater impulsive sensation seeking personality traits. They also tended to have a higher alcohol intake. Regression analysis showed that impulsive sensation seeking personality traits, depressive symptoms, alcohol intake, and age at PD onset were significant predictors of the syndrome.The authors say there is ample evidence to demonstrate a clear relationship between addiction proneness and impulsive sensation seeking personality traits. These personality traits are considered to be mediated by dopaminergic nerves projecting from the midbrain to the brain reward system. They predicted that, in addition to impulsive sensation seeking traits, depression and alcohol use may be associated with dopamine dysregulation syndrome since stress and previous exposure to alcohol are thought to enhance the effects of dopaminergic drugs on the brain reward system via cross-sensitisation.Although other potential risk factors were not investigated, including impaired cognitive control, impulsivity, and environmental, social, genetic and pharmacologic factors, the authors say their results may help identify patients vulnerable to compulsive dopamine drug use. If these patients are identified, measures can be taken to avoid the syndrome: "Vulnerable individuals may be counselled early in the course of management about the potential small risk of compulsive use of dopaminergic drug therapy and particular efforts made to limit drug increases." They suggest that other therapies, including subcutaneous apomorphine infusion, or low-dose clozapine or quetiapine, may help limit the need for dopamine increases in vulnerable patients.Reference...