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.