[Levodopa-induced psychosis in patients with idiopathic Parkinson disease]

To identify which clinical factors can modify the probability of the appearance of the psychotic syndromes in patients with idiopathic Parkinson's disease treated with levodopa.

214 patients were retrospectively studied to evaluate the appearance of hallucinosis, delusions or mental confusion, from the beginning of the treatment with levodopa to a transversal evaluation along the course of the disease. To determine which clinical factors were independent predictors of psychosis, a multivariate logistic regression model was obtained, using the variables for which the univariate studies showed p values under 0.25.

The multivariate model showed that the probability of developing psychosis during levodopa treatment was higher for the patients with intermediate or advanced stages of the disease (Hoehn and Yarh scale), at the beginning of the treatment (OR: 4.5; 95% CI: 1.86-11.23), when amantadine was administrated as associated drug (OR: 3.31; 95% CI: 1.19-9.23) and for the patients who presented motor fluctuations (OR: 3.08; 95% CI: 1.32-7.16). Univariate studies showed a significant association between levodopa psychosis and dyskinesias (univariate OR: 2.44; 95% CI: 1.12-5.33). Patients who suffered from psychotic complications had received significantly higher mean levodopa daily dose (p = 0.016) and the punctuation reached in the Folstein's Mini-Mental Scale was significantly lower (p = 0.0001).

Levodopa psychosis appears in a "bad prognostic" group of patients, characterized by a greater motor and cognitive impairment and by the occurrence of other levodopa central adverse effects, higher doses of levodopa and a more frequent administration of other antiparkinsonian drugs.