Plasma nitrate levels in deficit versus non-deficit forms of schizophrenia.

OBJECTIVE To determine whether nitric oxide production levels differ in patients with deficit and non-deficit forms of schizophrenia. METHODS We investigated plasma nitrate levels, an index of in vivo nitric oxide production, in patients with deficit syndrome (n = 11) and non-deficit syndrome (n = 14) and healthy controls (n = 12) with a combination of high-performance liquid chromatography and the Griess reaction. RESULTS There was no difference found in mean plasma nitrite levels, but plasma nitrate levels of patients with deficit syndrome were significantly lower than those with non-deficit syndrome (28.0 [SEM 2.5] micromol/L v. 44.2 [SEM 5.5] micromol/L, p < 0.05). CONCLUSIONS A decline in nitric oxide production may be involved in primary negative symptoms in schizophrenia.