McGovern Institute for Brain Research, MIT, Cambridge, Massachusetts.
Harvard Medical School, Boston, Massachusetts.
JAMA Netw Open. 2024 Sep 3;7(9):e2434354. doi: 10.1001/jamanetworkopen.2024.34354.
Cannabis is increasingly being used to treat medical symptoms, but the effects on brain function in those using cannabis for these symptoms are not known.
To test whether 1 year of cannabis use for medical symptoms after obtaining a medical cannabis card was associated with increased brain activation during working memory, reward, and inhibitory control tasks, areas of cognition affected by cannabis.
DESIGN, SETTING, AND PARTICIPANTS: This cohort study was conducted from July 2017 to July 2020 among participants from the greater Boston area who were recruited as part of a clinical trial of individuals seeking medical cannabis cards for anxiety, depression, pain, or insomnia symptoms. Participants were aged between 18 and 65 years. Exclusion criteria were daily cannabis use and cannabis use disorder at baseline. Data analysis was conducted from August 2021 to April 2024.
Outcomes were whole brain functional activation during tasks involving working memory, reward, and inhibitory control at baseline and after 1 year of medical cannabis card ownership.
Imaging was collected from participants before and 1 year after obtaining medical cannabis cards, with 57 participants at baseline (38 female [66.7%]; 6 [10.5%] Black and 45 [78.9%] White participants; 1 [1.8%] Hispanic participant; median [IQR] age, 34.0 [24.0-51.0] years) and 54 participants at 1 year (37 female [68.5%]; 4 [7.4%] Black and 48 [88.9%] White participants; 1 [1.9%] Hispanic participant, median [IQR] age, 36.5 [25.0-51.0] years). Imaging was also collected in 32 healthy control participants at baseline (22 female [68.8%]; 2 [6.2%] Black and 27 [84.4%] White participants; 3 [9.4%] Hispanic participants; median [IQR] age, 33.0 [24.8-38.2] years). In all groups and at both time points, functional imaging revealed canonical activations of the probed cognitive processes. No statistically significant difference in brain activation between the 2 time points (baseline and 1 year) in those with medical cannabis cards and no associations between changes in cannabis use frequency and brain activation after 1 year were found.
In this cohort study of adults obtaining medical cannabis cards for medical symptoms, no significant association between brain activation in the areas of cognition of working memory, reward, and inhibitory control and 1 year of cannabis use was observed. The results warrant further studies that probe the association of cannabis at higher doses, with greater frequency, in younger age groups, and with larger, more diverse cohorts.
大麻越来越多地被用于治疗医学症状，但对于因这些症状而使用大麻的人的大脑功能的影响尚不清楚。
测试在获得医用大麻卡后一年内因医疗症状使用大麻是否与工作记忆、奖励和抑制控制任务期间大脑激活增加有关，这些认知领域受到大麻的影响。
设计、地点和参与者：这项队列研究于 2017 年 7 月至 2020 年 7 月在马萨诸塞州大波士顿地区的参与者中进行，这些参与者是作为寻求治疗焦虑、抑郁、疼痛或失眠症状的医用大麻卡的临床试验的一部分招募的。参与者年龄在 18 至 65 岁之间。排除标准为基线时每日使用大麻和大麻使用障碍。数据分析于 2021 年 8 月至 2024 年 4 月进行。
结果是在基线和获得医用大麻卡 1 年后进行工作记忆、奖励和抑制控制任务时的全脑功能激活。
在获得医用大麻卡之前和之后，参与者都进行了影像学检查，基线时有 57 名参与者（38 名女性[66.7%]；6 名[10.5%]黑人，45 名[78.9%]白人参与者；1 名[1.8%]西班牙裔参与者；中位数[IQR]年龄，34.0[24.0-51.0]岁），1 年后有 54 名参与者（37 名女性[68.5%]；4 名[7.4%]黑人，48 名[88.9%]白人参与者；1 名[1.9%]西班牙裔参与者；中位数[IQR]年龄，36.5[25.0-51.0]岁）。在基线时，还对 32 名健康对照组参与者进行了影像学检查（22 名女性[68.8%]；2 名[6.2%]黑人，27 名[84.4%]白人参与者；3 名[9.4%]西班牙裔参与者；中位数[IQR]年龄，33.0[24.8-38.2]岁）。在所有组和两个时间点，功能成像都揭示了探测认知过程的典型激活。在有医用大麻卡的患者中，两个时间点（基线和 1 年）之间的大脑激活没有统计学上的显著差异，也没有发现大麻使用频率变化与 1 年后大脑激活之间的关联。
在这项针对因医疗症状而获得医用大麻卡的成年人的队列研究中，未观察到工作记忆、奖励和抑制控制认知领域的大脑激活与 1 年内大麻使用之间存在显著关联。这些结果需要进一步的研究来探究更高剂量、更频繁、在更年轻的年龄组以及更大、更多样化的队列中使用大麻的关联。
