The association of schizotypal traits with Prepulse Inhibition: a double approach exploration

<b>Introduction:</b> According to the <i>fully-dimensional approach</i>, schizotypy is a personality trait present in the population in a continuous manner while the <i>quasi-dimensional approach</i> emphasises its extreme presentations. In this study we examined the relationship between sensorimotor gating, a core risk-index of the schizophrenia-spectrum, and four schizotypal factors in a dimensional-wise and a dichotomising-wise approach. <b>Methods:</b> Two-hundred and eighty-three participants were assessed with the Schizotypal Personality Questionnaire and were tested for Prepulse Inhibition (PPI). Associations between the schizotypal factors and startle measures were examined with stepwise regressions (dimensional-wise approach). Individuals in the lower 20% or the upper 20% for each schizotypal factor were identified and between-group comparisons were conducted (dichotomising-wise approach). <b>Results:</b> We found that with both approaches, only high paranoid or negative schizotypy were associated with reduced PPI. The low negative schizotypy group had prolonged onset and peak latencies, indicating that prolonged stimulus detection accompanies superior sensorimotor gating in this group. <b>Conclusions:</b> The findings suggest that although differentiating the effects of the various schizotypal factors is primary, the approach employed is secondary. The study also adds evidence in the literature supporting PPI as a useful endophenotypic marker of the schizophrenia-spectrum and highlights the contribution of specific aspects of schizotypy.

**引言：**
根据全维度范式（fully-dimensional approach），分裂型特质是人群中以连续分布形式存在的一种人格特质；而准维度范式（quasi-dimensional approach）则着重强调其极端表现形式。本研究分别采用维度分析与二分法分析两种范式，探讨了作为精神分裂症谱系核心风险指标的感觉运动门控（sensorimotor gating）与四个分裂型特质因子之间的关联。

**研究方法：**
本研究共纳入283名参与者，采用分裂型人格问卷（Schizotypal Personality Questionnaire）对其进行评估，并开展前脉冲抑制（Prepulse Inhibition，PPI）检测。采用逐步回归分析（对应维度分析范式）探讨分裂型特质因子与惊反射指标间的关联；针对每个分裂型特质因子，筛选出得分处于最低20%与最高20%的个体，开展组间比较（对应二分法分析范式）。

**结果：**
本研究发现，无论采用哪种分析范式，仅高偏执型或高阴性分裂型特质与PPI减弱存在显著关联。低阴性分裂型特质组的起始潜伏期与峰值潜伏期均显著延长，提示该组在刺激检测过程延迟的同时，感觉运动门控功能更为优异。

**结论：**
本研究结果表明，尽管区分不同分裂型特质因子的效应是研究的核心所在，但所采用的分析方法并非关键因素。本研究为“前脉冲抑制可作为精神分裂症谱系的有效内表型标记（endophenotypic marker）”这一学术观点补充了实证证据，并明确了分裂型特质的特定维度所发挥的重要作用。