title: A single dose of L-DOPA changes perceptual experiences and decreases latent inhibition in Parkinson's disease.
abstract: Despite the well-known neuropsychiatric side effects of dopaminergic medications, the possible subjective psychotomimetic effects of a single dose of L-DOPA in newly diagnosed, drug-naïve patients with Parkinson's disease (PD) are not known. To investigate this question, we used a visual search task for latent inhibition (LI), the Community Assessment of Psychic Experiences (CAPE) scale, and visual analog scales for psychotomimetic effects (perception, relaxation, and dysphoria) in 28 de novo PD patients before (off) and after (on) the adminstration of L-DOPA and in 25 matched healthy control individuals. Results revealed increased LI in PD-off and decreased LI in PD-on relative to the control subjects. After the administration of L-DOPA, we observed a significant decline in LI in PD. L-DOPA also enhanced perceptual experiences (changes in subjective feelings in thinking, time perception, and mental "highness"). Greater reduction in LI was associated with enhanced perceptual experiences. These results suggest that a single dose of L-DOPA has a significant psychotomimetic effect, which is associated with decreased LI, a behavioral marker of psychosis-like experiences.
authors.affiliation: Neurology Department, Nyírő Gyula Hospital-National Institute of Psychiatry and Addictions, Budapest, Hungary.
authors.forename: Orsolya
authors.initials: O
authors.lastname: Györfi
authors.affiliation: National Institute for Medical Rehabilitation, Budapest, Hungary.|Department of Neurology, Semmelweis University, Budapest, Hungary.
authors.forename: Helga
authors.initials: H
authors.lastname: Nagy
authors.affiliation: Neurology Department, Nyírő Gyula Hospital-National Institute of Psychiatry and Addictions, Budapest, Hungary.
authors.forename: Magdolna
authors.initials: M
authors.lastname: Bokor
authors.affiliation: Department of Behavioral Sciences, Faculty of Medicine, University of Szeged, Szeged, Hungary.
authors.forename: Oguz
authors.initials: O
authors.lastname: Kelemen
authors.affiliation: Neurology Department, Nyírő Gyula Hospital-National Institute of Psychiatry and Addictions, Budapest, Hungary. szkeri@cogsci.bme.hu.|Department of Cognitive Science, Budapest University of Technology and Economics, Egry str. 1, Budapest, 1111, Hungary. szkeri@cogsci.bme.hu.|Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary. szkeri@cogsci.bme.hu.
authors.forename: Szabolcs
authors.initials: S
authors.lastname: Kéri
mesh_terms: D000978:Antiparkinson Agents / Q000008:administration & dosage / Q000009:adverse effects*; D001288:Attention / Q000187:drug effects; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D007980:Levodopa / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000188:drug therapy* / Q000523:psychology*; D010465:Perception / Q000187:drug effects*; D011605:Psychoses, Substance-Induced
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa
keywords: L-DOPA; Latent inhibition; Parkinson’s disease; Psychosis; Psychotomimetic effects