Department of Psychosis Studies, King's College London, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK.
Department of Psychosis Studies, King's College London, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK.
Eur Neuropsychopharmacol. 2015 Jan;25(1):26-37. doi: 10.1016/j.euroneuro.2014.11.018. Epub 2014 Dec 4.
Cannabis use can induce acute psychotic symptoms and increase the risk of schizophrenia. Impairments in inhibitory control and processing are known to occur both under the influence of cannabis and in schizophrenia. Whether cannabis-induced impairment in inhibitory processing is related to the acute induction of psychotic symptoms under its influence is unclear. We investigated the effects of acute oral administration of 10mg of delta-9-tetrahydrocannabinol (delta-9-THC), the main psychoactive ingredient of cannabis, on inhibitory control and regional brain activation during inhibitory processing in humans and examined whether these effects are related to the induction of psychotic symptoms under its influence using a repeated-measures, placebo-controlled, double-blind, within-subject design. We studied thirty-six healthy, English-speaking, right-handed men with minimal previous exposure to cannabis and other illicit drugs twice using functional magnetic resonance imaging (fMRI) while they performed a response inhibition (Go/No-Go) task. Relative to placebo, delta-9-THC caused transient psychotic symptoms, anxiety, intoxication and sedation, inhibition errors and impaired inhibition efficiency. Severity of psychotic symptoms was directly correlated with inhibition error frequency and inversely with inhibition efficiency under the influence of delta-9-THC. Delta-9-THC attenuated left inferior frontal activation which was inversely correlated with the frequency of inhibition errors and severity of psychotic symptoms and positively with inhibition efficiency under its influence. These results provide experimental evidence that impairments in cognitive processes involved in the inhibitory control of thoughts and actions and inferior frontal function under the influence of cannabis may have a role in the emergence of transient psychotic symptoms under its influence.
大麻使用会诱发急性精神病症状，并增加精神分裂症的风险。已知在大麻的影响下以及在精神分裂症中都会发生抑制控制和加工方面的损伤。大麻引起的抑制加工损伤是否与在其影响下急性诱发精神病症状有关尚不清楚。我们研究了 10 毫克 delta-9-四氢大麻酚（大麻的主要精神活性成分）急性口服给药对人类抑制加工期间抑制控制和区域大脑激活的影响，并使用重复测量、安慰剂对照、双盲、被试内设计检查这些影响是否与在其影响下诱发精神病症状有关。我们使用功能磁共振成像（fMRI）在两次研究中研究了 36 名健康的、英语流利的、右利手的男性，他们以前接触大麻和其他非法药物的次数很少。他们在执行反应抑制（Go/No-Go）任务时进行了 fMRI 扫描。与安慰剂相比，Delta-9-THC 引起短暂的精神病症状、焦虑、中毒和镇静、抑制错误和抑制效率受损。精神病症状的严重程度与 Delta-9-THC 影响下的抑制错误频率直接相关，与抑制效率成反比。Delta-9-THC 减弱了左侧额下回的激活，这与抑制错误的频率以及 Delta-9-THC 影响下的精神病症状严重程度呈负相关，与抑制效率呈正相关。这些结果提供了实验证据，表明在大麻影响下，涉及思想和行为抑制控制的认知过程以及额下回功能的损伤可能在其影响下短暂精神病症状的出现中起作用。
