Background: Sustained drug therapy in Parkinson’s disease may alter the psychomotor responses to acute challenges with dopaminergic drugs, L-dopa and methylphenidate, and cause cross sensitisation.
Methods: The mood, psychomotor and reward potentiating effects of an acute challenge with L-dopa and methylphenidate on separate occasions were assessed under double blind (medication naïve) conditions after a placebo and then the testing sessions were repeated in the same (medication experienced) patients following a median period of 16.7 months of continuous dopaminergic drug therapy.
Results: In the medication naïve condition, affect was not changed by L-dopa or methylphenidate and only L-dopa improved motor function. In the medication experienced condition, active drugs improved positive affect compared with the medication naïve condition and there was an enhanced effect of L-dopa on motor function. Reward responsivity was enhanced by both L-dopa and methylphenidate in medication naïve and experienced conditions.
Conclusion: Sustained dopaminergic drug therapy augments the motor effects of an acute challenge with L-dopa and induces euphoriant effects to L-dopa and methylphenidate challenges.
Statistics from Altmetric.com
Competing interests: None.
Ethics approval: The study was approved by the Joint Ethics Committee of the National Hospital for Neurology and Neurosurgery and Institute of Neurology.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.