Hagenmuller Florence, Heekeren Karsten, Roser Patrik, Haker Helene, Theodoridou Anastasia, Walitza Susanne, Rössler Wulf, Kawohl Wolfram
The Zurich Program for Sustainable Development of Mental Health Services (ZInEP), University of Zurich, Zurich, Switzerland.
Department of Psychiatry, Psychotherapy and Psychosomatics, University of Zurich, Zurich, Switzerland.
Front Psychiatry. 2019 Feb 13;10:47. doi: 10.3389/fpsyt.2019.00047. eCollection 2019.
Somatosensory evoked potentials (SEPs) enable the investigation of thalamocortical and early cortical processing. Previous studies reported alterations of SEPs in patients with schizophrenia as well as in individuals in the prodromal stage. Moreover, cannabis use as an environmental risk factor for the development of schizophrenia has been demonstrated to influence SEP parameters in individuals at risk to develop psychosis. The aim of this study was to explore the course of SEP changes and the impact of concomitant cannabis use in individuals at risk to develop psychosis who sought medical help. Median nerve SEPs including high-frequency oscillations (HFOs) superimposed on the primary cortical response (N20) were investigated using multichannel EEG in individuals ( = 54 at baseline) remaining at risk to develop psychosis at follow-up after 1 year (high-risk: = 19; ultra-high-risk: = 27) vs. subjects with conversion to psychosis ( = 8) and a healthy control group ( = 35). Longitudinal and cross-sectional analyses of SEP components as estimated by dipole source analysis were performed. The longitudinal development of the N20 strength depended on cannabis use. In cannabis non-users, a greater decrease of N20 strengths over time was associated with more negative symptoms at baseline. At baseline, converters did not differ from subjects remaining at risk. At follow-up, converters showed increased low- and high-frequency activity than at-risk subjects and did not differ from controls. The results of this study lead to the suggestion that the deficits in early somatosensory processing in individuals at risk to develop psychosis may not represent a marker for a genetic risk for psychosis but rather reflect state-dependent factors such as negative symptoms. On the other hand, the transition to psychosis seems to represent an interstage between reduced sensory registration from the at-risk state and gating deficits in the chronic state.
体感诱发电位（SEPs）有助于研究丘脑皮质及早期皮质处理过程。既往研究报道了精神分裂症患者以及前驱期个体的SEPs改变。此外，大麻使用作为精神分裂症发生的一个环境风险因素，已被证明会影响有患精神病风险个体的SEP参数。本研究的目的是探讨有患精神病风险且寻求医疗帮助的个体中SEP变化的过程以及同时使用大麻的影响。使用多通道脑电图对包括叠加在初级皮质反应（N20）上的高频振荡（HFOs）的正中神经SEPs进行了研究，研究对象为随访1年后仍有患精神病风险的个体（基线时n = 54）（高风险：n = 19；超高风险：n = 27），与已转化为精神病的受试者（n = 8）和健康对照组（n = 35）进行比较。通过偶极子源分析对SEP成分进行了纵向和横断面分析。N20强度的纵向发展取决于大麻使用情况。在不使用大麻的个体中，随着时间推移N20强度的更大下降与基线时更多的阴性症状相关。在基线时，已转化者与仍有风险的受试者没有差异。在随访时，已转化者显示出比有风险受试者更高的低频和高频活动，且与对照组没有差异。本研究结果表明，有患精神病风险个体早期体感处理缺陷可能不代表精神病遗传风险的标志物，而更可能反映诸如阴性症状等状态依赖性因素。另一方面，向精神病的转变似乎代表了从有风险状态下感觉登记减少到慢性状态下门控缺陷之间的一个中间阶段。
