P50 sensory gating: impact of high vs. low schizotypal personality and smoking status.

Sensory gating deficits are seen in individuals with schizophrenia and schizotypal disorders, yet smoking influence, regional or lateral difference effects are rarely assessed. We examined sensory gating in smokers and non-smokers within university-level high and low schizotypal personality (HiS and LoS) groups using [Raine, A., 1991. The Schizotypal Personality Questionnaire (SPQ): A measure of schizotypal personality based on DSM-III-R criteria. Schizophr. Bull. 17, 555-564] Schizotypal Personality Questionnaire. Among 39 (18 men; 19 smokers) right-handed undergraduates, a paired-tone paradigm (40 pairs; 10 s ISI; 70 dB, 1000 Hz) was presented in two conditions (smokers while abstaining and after smoking). Sensory gating [S2(P50-N40)/S1(P50-N40)] was assessed at frontal, fronto-central, central, centro-parietal, and parietal midline and lateralized sites. Sensory gating was better at (1) midline than left/right hemispheric sites, and (2) fronto-central and central midline sites. At fronto-central/central lateral sites, (1) among non-smokers, better sensory gating occurred in LoS than HiS, (2) among smokers, better sensory gating occurred in HiS than LoS, and (3) among LoSs, smokers showed less sensory gating than non-smokers. No acute smoking effects emerged. Unlike schizophrenia studies, smoking did not impact sensory gating. Differences among smokers and non-smokers in LoS and HiS groups reinforce need to evaluate both smoking and schizotypal characteristics, as well as midline and lateral sites in anterior to posterior regions, in sensory gating studies.