Objective:Long-term exposure to the psychoactive ingredient in cannabis, delta-9-tetrahydrocanabinol (THC), has been consistently raised as a notable risk factor for schizophrenia. Additionally, cannabis is frequently used as a coping mechanism for individuals diagnosed with schizophrenia. Cannabis use in schizophrenia has been associated with greater severity of psychotic symptoms, non-compliance with medication, and increased relapse rates. Neuropsychological changes have also been implicated in long-term cannabis use and the course of illness of schizophrenia. However, the impact of co-occurring cannabis use in individuals with schizophrenia on cognitive functioning is less thoroughly explored. The purpose of this meta-analysis was to examine whether neuropsychological test performance and symptoms in schizophrenia differ as a function of THC use status. A second aim of this study was to examine whether symptom severity moderates the relationship between THC use and cognitive test performance among people with schizophrenia.Participants and Methods:Peer-reviewed articles comparing schizophrenia with and without cannabis use disorder (SZ SUD+; SZ SUD-) were selected from three scholarly databases; Ovid, Google Scholar, and PubMed. The following search terms were applied to yield studies for inclusion: neuropsychology, cognition, cognitive, THC, cannabis, marijuana, and schizophrenia. 11 articles containing data on psychotic symptoms and neurocognition, with SZ SUD+ and SZ SUD- groups, were included in the final analyses. Six domains of neurocognition were identified across included articles (Processing Speed, Attention, Working Memory, Verbal Learning Memory, and Reasoning and Problem Solving). Positive and negative symptom data was derived from eligible studies consisting of the Positive and Negative Syndrome Scale (PANSS), the Scale for the Assessment of Positive Symptoms (SAPS), the Scale for the Assessment of Negative Symptoms (SANS), Self-Evaluation of Negative Symptoms (SNS), Brief Psychiatric Rating Scale (BPRS), and Structured Clinical Interview for DSM Disorders (SCID) scores. Meta analysis and meta-regression was conducted using R.Results:No statistically significant differences were observed between SZ SUD+ and SZ SUD-across the cognitive domains of Processing Speed, Attention, Working Memory, Verbal Learning Memory, and Reasoning and Problem Solving. Positive symptom severity was found to moderate the relationship between THC use and processing speed, but not negative symptoms. Positive and negative symptom severity did not significantly moderate the relationship between THC use and the other cognitive domains.Conclusions:Positive symptoms moderated the relationship between cannabis use and processing speed among people with schizophrenia. The reasons for this are unclear, and require further exploration. Additional investigation is warranted to better understand the impact of THC use on other tests of neuropsychological performance and symptoms in schizophrenia.

中文翻译：

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52 精神分裂症与同时使用大麻的神经心理学测试表现和症状数据的差异

目的：长期接触大麻中的精神活性成分 δ-9-四氢大麻酚 (THC)，一直被认为是精神分裂症的一个显着危险因素。此外，大麻经常被用作精神分裂症患者的应对机制。精神分裂症患者使用大麻与更严重的精神病症状、不遵守药物治疗以及复发率增加有关。神经心理变化也与长期使用大麻和精神分裂症的病程有关。然而，精神分裂症患者同时使用大麻对认知功能的影响尚未得到彻底探讨。这项荟萃分析的目的是检查精神分裂症的神经心理学测试表现和症状是否因 THC 使用状态而有所不同。本研究的第二个目的是检查症状严重程度是否会调节精神分裂症患者 THC 使用与认知测试表现之间的关系。 参与者和方法：比较有和没有大麻使用障碍的精神分裂症的同行评审文章（SZ SUD+；SZ SUD-） ）选自三个学术数据库；奥维德、谷歌学术和 PubMed。以下搜索词用于纳入研究：神经心理学、认知、认知、THC、大麻、大麻和精神分裂症。最终分析中纳入了 11 篇包含 SZ SUD+ 和 SZ SUD- 组精神病症状和神经认知数据的文章。所包含的文章确定了神经认知的六个领域（处理速度、注意力、工作记忆、言语学习记忆、推理和问题解决）。阳性和阴性症状数据来自合格的研究，包括阳性和阴性症状量表（PANSS）、阳性症状评估量表（SAPS）、阴性症状评估量表（SANS）、自我评估阴性症状 (SNS)、简要精神病评定量表 (BPRS) 和 DSM 疾病结构化临床访谈 (SCID) 评分。使用 R 进行荟萃分析和荟萃回归。结果：在处理速度、注意力、工作记忆、言语学习记忆以及推理和问题解决等认知领域，SZ SUD+ 和 SZ SUD- 之间没有观察到统计学上的显着差异。研究发现，阳性症状的严重程度可以调节 THC 使用和处理速度之间的关系，但不能调节阴性症状。阳性和阴性症状的严重程度并没有显着调节 THC 使用与其他认知领域之间的关系。结论：阳性症状调节了精神分裂症患者大麻使用与处理速度之间的关系。其原因尚不清楚，需要进一步探讨。