School of Psychology, University of Wollongong, Wollongong, NSW, 2522, Australia.
Psychopharmacology (Berl). 2012 Aug;222(3):507-18. doi: 10.1007/s00213-012-2676-2. Epub 2012 Mar 9.
Cannabis use is prevalent among the early psychosis (EP) population. The event-related potentials, mismatch negativity (MMN) and P3a are reduced in EP. Cannabinoids have been shown to modulate N-methyl-D-aspartate receptors which are involved in MMN generation.
This study is the first to investigate the effects of cannabis use on MMN/P3a in EP.
EP was defined as a history of psychosis or psychotic symptoms with no progression to date to chronic schizophrenia. Twenty-two EP patients with cannabis use (EP + CANN), 22 non-cannabis-using EP patients (EP-CANN) and 21 healthy controls participated in this study. MMN/P3a was elicited using a two-tone, auditory paradigm with 8% duration deviants.
As expected, EP-CANN showed marked reductions in MMN/P3a amplitudes compared to controls. However, EP + CANN showed evidence of a different pattern of neurophysiological expression of MMN/P3a compared to non-using patients, most notably in terms of delayed frontal MMN/P3a latencies.
This study provides further evidence that MMN/P3a deficits are present during early psychosis and suggests that this biomarker may have utility in differentiating substance- from non-substance-related psychoses.
大麻的使用在早期精神病（EP）人群中很普遍。事件相关电位、失匹配负波（MMN）和 P3a 在 EP 中减少。大麻素已被证明可以调节 N-甲基-D-天冬氨酸受体，该受体参与 MMN 的产生。
这项研究首次调查了大麻使用对 EP 中的 MMN/P3a 的影响。
EP 被定义为有精神病或精神病症状的病史，但迄今为止没有进展为慢性精神分裂症。22 名使用大麻的 EP 患者（EP+CANN）、22 名未使用大麻的 EP 患者（EP-CANN）和 21 名健康对照者参加了这项研究。使用双音听觉范式和 8%持续时间偏差引出 MMN/P3a。
正如预期的那样，EP-CANN 与对照组相比，MMN/P3a 幅度明显降低。然而，EP+CANN 表现出与非使用患者相比，MMN/P3a 的神经生理表达的不同模式，最明显的是在额叶 MMN/P3a 潜伏期延迟方面。
这项研究进一步证明了 MMN/P3a 缺陷存在于早期精神病中，并表明该生物标志物可能有助于区分物质相关和非物质相关的精神病。
