PRL and multiple system atrophy: This was also seen in a multivariate analysis including prolactin serum levels as dependent variable and diagnoses (PSP/CBS, MSA, PD, controls), sex, age and dopaminergic antiparkinsonian treatment as independent variables revealed that serum prolactin levels were influenced only by antiparkinsonian treatment (p < 0.001), but not by diagnoses, sex and age (p = ns).