[P50 sensory gating studies in schizophrenics: a systematic review].

Objective: To conduct a systematic review of P50 sensory gating studies in schizophrenics and the change between before and after treatment.

Methods: Standard search strategy for the Cochrane Review Group was performed by two review authors. Searches were made in PubMed, EMBase, Web of knowledge, PsycINFO, Cochrane Library, CNKI, Wanfang, VIP and CBMDisc databases. STROBE (strengthening the reporting of observational studies in epidemiology) was used to assess the methodological quality of the studies. RevMan 5.0.23 software was employed to conduct a Meta analysis.

Results: Seventy-one literatures were reviewed and 7 studies met the inclusion criteria for a Meta analysis. The meta-analysis of random effects showed that S1 amplitude was lower in the schizophrenia group than in the normal control group (P = 0.02). And S2 amplitude was significant higher in schizophrenia group than the normal control group (P = 0.001). There were no statistical significance in S1 and S2 latency between two groups (P = 0.34 and P = 0.19 respectively). P50 Ratio in schizophrenia group was significantly higher than the normal control group. And the difference was statistically significant [Z = 11.46, P < 0.00001, combined SMD = 44.18, 95%CI (36.62, 51.74)]. However the P50 difference showed no significant difference (P = 0.14). An analysis of fixed effects showed that the P50 Ratio difference was not statistically significant in schizophrenics between before and after treatment (P = 0.19).

Conclusion: The schizophrenics have a sensory gating dysfunction. P50 Ratio is a stable and reliable indicator of sensory gating function. Antipsychotics may partly enhance P50 sensory gating in schizophrenics, but can not completely reverse the defect of P50 suppression.