The niacin skin flush test in schizophrenia: a replication study.

The aim of this study was to confirm a recent report that the non-invasive niacin skin flush test can be used to demonstrate impaired arachidonic acid-related signal transduction in schizophrenia. The response to topical aqueous methyl nicotinate solution was recorded at five-minute intervals over 20 minutes in 21 patients with schizophrenia, and in 20 age- and sex-matched normal individuals with no personal or family psychiatric history. The response was significantly lower in the patients with schizophrenia. At a concentration of 0.001 M, at the 15-minute timepoint, only two out of the 21 patients with schizophrenia showed a response, compared with 15 out of 20 of the controls (p < 0.00002), giving a sensitivity of the niacin skin test of 90% and a specificity of 75%. Our results are therefore consistent with the previous published report and suggest that this test may be useful clinically in the diagnosis of schizophrenia.