We studied the effect of the atypical neuroleptic clozapine (CLO) on h
omovanillic acid (HVA) in cerebrospinal fluid (CSF) in five patients w
ith spasmocid torticollis. Lumbar puncture was performed before and on
the seventh day of CLO treatment. Although an HVA elevation was to be
expected because of the antidopaminergic action of CLO, statistical a
nalysis failed to reveal any significant increase of HVA under CLO tre
atment. Thus significance of CSF HVA may be less important for the des
cription of antidopaminergic action of neuroleptics than previously as
sumed.