It is impossible to ignore the rapidly growing interest in the therapeutic use of psychedelics. Once marginalized as elements of counterculture, substances such as lysergic acid diethylamide (LSD) have catapulted into the limelight. Traditionally, psychedelic therapy has involved administering “macro” doses, leading to potent psychoactive effects (the psychedelic “trip”). Although these effects are assumed to have therapeutic merits some argue that they may limit the broader application of these emerging interventions [1]. “Microdosing”, an alternative approach that involves taking sub-hallucinogenic doses of psychedelics for mental health benefit, is being evaluated in clinical populations. At the same time, mechanisms of effects of psychedelics (both macro and microdosed) are being evaluated.

In this context, the recent report by Murray et al. published in Neuropsychopharmacology is a relevant contribution to the field [2]. Pooling data from three previous studies, the authors evaluated the relationship between electroencephalography (EEG) measures of neural complexity across drug classes and doses in healthy participants. Neural complexity refers to the diversity and richness of brain activity patterns. It is hypothesized that serotonin 2A receptor (5-HT_2A) receptor agonism induces changes in neural complexity during the subjective psychedelic experience, serving as a key mechanism for therapeutic effects [2]. Murray et al. conducted a secondary analysis involving 73 healthy adults that compared microdoses of either LSD (13 and 26 µg), tetrahydrocannabinol (THC) (7.5 and 15 mg), or methamphetamine (10 and 20 mg) against placebo. Each participant underwent three sessions during which they received either a placebo or one of two doses of the respective drugs. They assessed clinical measures including the 5 Dimensions of Altered State of Consciousness (5D-ASC), a self-reported measure of the subjective psychedelic experience, and EEG measures of neural complexity (Limpel-Ziv Complexity).

人们对迷幻药治疗用途的兴趣迅速增长，这是不容忽视的。麦角酸二乙酰胺 (LSD) 等物质一度被视为反主流文化的元素，如今却一跃成为人们关注的焦点。传统上，迷幻疗法涉及施用“宏观”剂量，从而产生有效的精神作用（迷幻“旅行”）。尽管这些效应被认为具有治疗价值，但一些人认为它们可能会限制这些新兴干预措施的更广泛应用[1]。 “微剂量”是一种替代方法，涉及服用亚致幻剂量的致幻剂以有益于心理健康，目前正在临床人群中进行评估。同时，正在评估致幻剂（大剂量和微剂量）的作用机制。

在这种背景下，默里等人最近的报告。发表在Neuropsychopharmacology上的文章是对该领域的相关贡献 [2]。作者汇集了之前三项研究的数据，评估了健康参与者的不同药物类别的神经复杂性的脑电图 (EEG) 测量值和剂量之间的关系。神经复杂性是指大脑活动模式的多样性和丰富性。据推测，5-羟色胺 2A 受体 (5-HT _2A ) 受体激动作用会在主观迷幻体验过程中引起神经复杂性的变化，成为治疗效果的关键机制 [2]。默里等人。对 73 名健康成年人进行了二次分析，将微剂量 LSD（13 和 26 µg）、四氢大麻酚（THC）（7.5 和 15 mg）或甲基苯丙胺（10 和 20 mg）与安慰剂进行比较。每位参与者接受了三个疗程，期间他们接受安慰剂或两种剂量的相应药物中的一种。他们评估了临床测量，包括意识改变状态的 5 个维度 (5D-ASC)、主观迷幻体验的自我报告测量以及神经复杂性的脑电图测量 (Limpel-Ziv 复杂性)。