Animals and men turn preferentially away
from the hemisphere with the more active dopamine
(DA) system. Consistent with the idea of a right–hemispheric
hyperdopaminergia in schizophrenia, a leftsided
turning bias was described for unmedicated psychotic
patients. We investigated the modulating role of
DA and schizophrenia–like thought on whole–body
turns in a controlled double–blind study. The number of
veers to either side when walking blindfolded straight
ahead (20 meter) was assessed in 40 healthy righthanded
men (20 men received levodopa, the remaining
participants placebo). Side preferences were analyzed in
terms of individuals

positive (Magical Ideation, MI) and
negative (Physical Anhedonia, PhysAn) schizotypal features.
In the placebo group, increasing MI scores were
related to increasing left–sided veering and increasing
PhysAn scores were related to increasing right–sided
veering. In the levodopa group, this relationship between
preferred veering side and type of schizotypy was
reversed. The finding in the placebo group suggests an
association between MI and a relative right–hemispheric
hyperdopaminergia. Unexpectedly, levodopa
did not enhance this veering bias, but reversed it, suggesting
that psychosis–protective mechanisms exist in
the healthy positive

schizotypic

brain. Also unexpectedly,
levodopa made

anhedonics

veer like

magics

after
placebo, suggesting that DA agonists suppress negative
schizotypal symptoms.
Key words dopamine - asymmetry - hemispheres - schizotypy - turning - neuropharmacology