Serum d- and l-lactate, pyruvate and glucose levels in individuals with at-risk mental state and correlations with clinical symptoms.

AIM

Little information exists on the peripheral metabolite levels in individuals with at-risk mental state who meet the criteria for a high-risk state of psychosis. Here, we aimed to investigate serum levels of glucose, pyruvate and d- and l-lactate, which may act as a signalling molecule for learning and memory in neuronal cells.

METHODS

High performance liquid chromatography or commercial kits were used to assess serum metabolites in individuals with attenuated psychosis symptoms of at-risk mental state (n = 24, men = 12) who were not receiving antipsychotics. The metabolite levels of these individuals were compared with those of age- and sex-matched healthy individuals (controls, n = 23, men = 11). Correlations between the metabolites and clinical symptoms of at-risk mental state were also examined.

RESULTS

Individuals with at-risk mental state had higher serum glucose levels than did controls (P = 2.18 × 10 ), while no significant difference in pyruvate levels were observed between the groups. Individuals with at-risk mental state had significantly lower serum l-lactate levels than did controls (P = 6.31 × 10 ), while no differences in d-lactate levels were observed. Furthermore, a negative correlation was identified between serum l-lactate levels and Positive and Negative Syndrome Scale negative symptoms scores (r = -0.5651, P = 4.01 × 10 ) in individuals with at-risk mental state.

CONCLUSIONS

We found that, compared with controls, individuals with at-risk mental state have reduced serum l-lactate levels, which may predate psychosis onset, and may be involved in the related negative symptoms.