A noticeable result is the heterogeneity of the reactions
in schizophrenic patients. Most of these patients
exhibit reduced flushing, but there are a few patients
who show a very strong skin reaction after the application
of methyl nicotinate. These heterogeneous
results cannot, as yet, be explained by the membrane
hypothesis. It is possible that the extent of flushing is
related to the amount of positive or negative symptoms
that characterize a patient. Glen et al. (1994) published
a study that showed significant differences in the fatty
acid composition of the plasma and membranes of red
blood cells between schizophrenic patients with predominately
positive symptoms and other patients with
predominately negative symptoms. It would be interesting,
therefore, if future studies related symptom
scores to redness scores. Associations with medication
use, gender and age also need to be addressed. A recent
study shows a weaker response in men than women and
a negative relationship between age and responsiveness
to niacin (Smesny et al., 2004). In our study, the use of
medication, gender and age did not affect the differences
between the groups. Further research into the
background of the diversity of the skin reactions within
the population of schizophrenic patients is of primary
importance.