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Results for “Cognitive Enhancement”

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At least 19 recordsLinked to original sources

PubMed2026

Dissociable neural mechanisms of cognitive enhancement through transcranial stimulation and behavioral training.

BACKGROUND: Transcranial direct current stimulation (tDCS) and adaptive working memory (WM) training are promising cognitive enhancement approaches; however, their neural mechanisms and potential synergies remain poorly understood. OBJECTIVE: We directly compared how tDCS and WM training modulate neural oscillations during WM performance and examined whether combining both interventions produces additive effects. METHODS: We randomized 112 healthy adults into four groups: control (sham tDCS + non-adaptive 1-back), tDCS-only (active tDCS + non-adaptive 1-back), training-only (sham tDCS + adaptive n-back training), or combined (active tDCS + adaptive training). Participants underwent five daily intervention sessions. We recorded high-density EEG during transfer n-back tasks at baseline, post-intervention, and one-week follow-up. RESULTS: All active interventions improved WM performance relative to the control group, with the combined group showing the largest gains (n-back accuracy: +15.6% vs. + 10.1% tDCS-only, +9.7% training-only, +0.7% control; all p < 0.001). Critically, tDCS selectively increased gamma-band (30-50 Hz) power in the frontal and parietal regions (cluster p = 0.018, d > 1.0), whereas WM training enhanced frontal theta-band (4-8 Hz) power and theta-gamma phase-amplitude coupling (both cluster p < 0.012, d > 0.85). The combined group exhibited both neural signatures. Brain-behavior correlations revealed dissociable relationships: gamma increases predicted n-back accuracy improvements (r = 0.61, p < 0.001), whereas theta enhancements correlated with operation span gains (r = 0.58, p = 0.002). CONCLUSIONS: tDCS and WM training enhance cognition through distinct yet complementary neural mechanisms: tDCS via gamma-mediated cortical excitability and WM training via theta-mediated cognitive control. These findings provide neurophysiological evidence for multimodal enhancement strategies that target parallel pathways within WM networks.

Humans↗

PubMed2026

Effect of cognitive enhancement therapy for early course schizophrenia on gray matter volume: A confirmatory multisite randomized clinical trial.

BACKGROUND: Cognitive Enhancement Therapy (CET) is an evidence-based cognitive remediation intervention for early course schizophrenia with established benefits for cognition. CET may protect against broad temporolimbic gray matter volume loss associated with cognitive improvement, but this finding has yet to be replicated. This research reexamined if CET protects against temporolimbic gray matter volume loss in an independent and larger multisite early course sample, and if this neuroprotective effect predicts cognitive and social adjustment improvement. METHODS: Ninety-nine participants with early course schizophrenia completed MRI, cognitive, and social adjustment assessments at baseline, 9 (mid-treatment), and 18 (end of treatment) months. Linear mixed-effects models examined the differential impact of CET (n = 56) compared to Enriched Supportive Therapy (n = 43) on temporolimbic gray matter volume in regions-of-interest (ROIs) that previously demonstrated CET-related neuroprotection (primary ROIs), as well as frontotemporal ROIs outlined in the first trial (secondary ROIs). RESULTS: The right rostral anterior cingulate was the only primary ROI to demonstrate a significant group × time interaction, but was unrelated to cognitive and social adjustment change. No secondary ROIs exhibited a differential treatment effect. CONCLUSION: This confirmatory trial did not recapitulate the observed broad pattern of CET-related temporolimbic gray matter volume neuroprotection. Consistent with the larger literature demonstrating limited evidence of cognitive remediation effects on the brain in schizophrenia, these findings underscore the need for continued investigation of CET-related changes with other neuroimaging modalities, especially given its established cognitive benefits. Such information is critical for cognitive remediation optimization based on validated therapeutic mechanisms.

Humans↗

PubMedDate not supplied

Differential methods of enhancing cognitive growth in urban preschool children.

The investigation was carried out to design and test more purposeful and structured methods of promoting intellectual growth in culturally deprived preschool children. The relative merits of providing specific cognitive training both in a nursery setting and in the home through the influence of the mother were assessed. Four groups each of 15 children were involved in the experiment, which extended over a period of four months. Gains were confirmed for both general intelligence and linguistic competence. Both the two nursery groups and the experimental "home" group all showed considerable improvement, the latter being comparable to the nursery control group.

Child Development↗

PubMed1978

Long-term durability and transfer of enhanced conceptual performance in the elderly.

To evaluate the durability and transfer of enhanced cognitive functioning in the elderly, subjects (ages 64 to 84) who had previously participated in a unidimensional concept identification study were tested on a bidimensional conjunctive concept identification problem. The conjunctive problem was administered approximately 12 mo after completion of the unidimensional study. In the earlier unidimensional study, substantial and equivalent improvement had been found with both a training group and a reinforced training group. In this study, efficient conjunctive problem solving was found with the (unidimensional) training group, showing that enhanced cognitive performance can be durable and transfer to a similar task. Durability and trasnfer were not observed with the (unidimensional) reinforced training group, however, a finding that appears to have resulted from the extrinsic reinforcement token system employed in the unidimensional training with that group.

Age Factors↗

PubMed2026

Dissociating behavioral, neural and experiential effects of prefrontal HD-tDCS during conflict resolution.

Inconsistent evidence regarding the cognitive effects of transcranial direct current stimulation (tDCS) highlights the need for more comprehensive approaches to assess its impact. This study aimed to investigate the effects of high-definition tDCS (HD-tDCS) on conflict resolution by combining behavioral, neural, and subjective experience measures. Sixty participants were randomly assigned to anodal, cathodal, or sham HD-tDCS groups and completed a 30-min flanker task. EEG was recorded during the first and last blocks (without stimulation), while stimulation was applied during the intermediate blocks of the task. Using a multidimensional methodological approach including Drift-Diffusion Modeling (DDM), EEG spectral analysis, Lempel-Ziv complexity, and Temporal Experience Tracing (TET), we assessed the cognitive, neural, and phenomenological effects of stimulation. Behavioral results indicated no significant improvements in reaction times or accuracy across the stimulation groups. Similarly, DDM parameters showed no effect of HD-tDCS on latent cognitive processes. However, EEG data revealed a significant reduction in neural complexity in the anodal group during resting-state, suggesting a stabilization or reorganization of neural dynamics. Subjective experience analysis identified two distinct clusters of task-related feelings, though time spent in these experiential states did not differ between groups. Interestingly, sensation of stimulation was significantly higher for anodal stimulation than sham when analyzed as a single dimension. Despite null behavioral effects, this study provides important insights into the neural and subjective responses to HD-tDCS and highlights the value of integrating complementary multidimensional approaches to better characterize brain stimulation effects. These findings contribute to the ongoing debate about the efficacy of tDCS in cognitive enhancement.

Humans↗

PubMed2026

Effectiveness of transcranial direct current stimulation with and without positive mood induction on worry and transdiagnostic cognitive-emotional processes: A randomized controlled trial.

The present study investigated the effectiveness of transcranial direct current stimulation (tDCS), with and without positive mood induction, on worry and key transdiagnostic cognitive-emotional processes, including attentional bias, working memory, problem solving, and emotion regulation, in individuals with high levels of worry. This single-blind randomized controlled trial included 45 individuals with high levels of worry. After a structured clinical interview, participants were randomly assigned, with gender balancing, to one of three groups: (1) tDCS alone, (2) tDCS combined with positive mood induction, or (3) a sham control group. Outcome measures were administered at three time points (pretest, posttest, and one-month follow-up) and assessed attentional bias (Dot Probe Task), working memory (1-back task), problem solving (Tower of London task), emotion regulation (Gross's Emotion Regulation Questionnaire), and worry severity (Penn State Worry Questionnaire; PSWQ). Repeated-measures ANOVA showed that both active groups (tDCS alone and tDCS + positive mood induction) significantly improved attentional bias, worry, working memory, problem solving, and emotion regulation compared to controls (p < 0.05). The combined intervention produced significantly greater gains than tDCS alone in working memory, problem solving, emotion regulation (p < 0.05), and reductions in attentional bias and worry (p < 0.001). All effects persisted at one-month follow-up (p < 0.05). tDCS reduces worry and attentional bias and enhances cognition and emotion regulation in individuals with high levels of worry. The combined intervention produced larger and more sustained improvements than tDCS alone across the assessed behavioral outcomes. These findings support further investigation of combining tDCS with structured positive mood induction while the mechanisms underlying the additional benefits remain to be established.

Humans↗

PubMed1978

The effects of hyperbaric and normobaric oxygen on cognitive impairment in the elderly.

Eighty-two elderly subjects with significant cognitive impairment were randomly assigned to treatment with either hyperbaric oxygen, hyperbaric air, normobaric oxygen, or normobaric air. Treatment consisted of two 90-minute sessions a day for 15 consecutive days. Subjects were evaluated on measures of memory and intellectual capacity, as well as on psychiatric symptom rating scales. Results immediately after treatment and at one, two, three, and eight weeks following treatment did not show enhanced cognitive functioning or significantly greater symptom reduction in experimental subjects who received either normobaric or hyperbaric oxygen as compared to controls who received hyperbaric or normobaric air. There was also no evidence of differential treatment effects as a function of initial severity of illness, sex, response to a CO2 loading test, or presumed evidence of cerebrovascular disease.

Aged↗

PubMed2026

Dual Transcranial Direct Current Stimulation Modulates Hierarchical Functional Network Organization in Post-Stroke Cognitive Impairment: A Randomized Controlled Trial.

OBJECTIVE: To evaluate the clinical efficacy of dual transcranial direct current stimulation (tDCS) in patients with post-stroke cognitive impairment (PSCI) and to explore the effects on the hierarchical organization of functional brain networks, ranging from regional synchronization to inter-regional connectivity and global network topology. METHODS: In this randomized, double-blind, sham-controlled trial, 74 PSCI patients received conventional therapy alongside either active dual-tDCS (n = 38) or sham stimulation (n = 36). Active tDCS targeted the dorsolateral prefrontal cortex (DLPFC) via anodal-left/cathodal-right nodes (2.0 mA, 20 min/day, 20 sessions). The primary outcome was the Montreal Cognitive Assessment (MoCA). Secondary outcomes included the Mini-Mental Status Examination (MMSE), Stroop Test (ST), Trail Making Test (TMT), Wechsler Memory Scale (WMS), and Barthel Index (BI). A subgroup of 36 participants (18 per group) underwent resting-state functional magnetic resonance imaging (rs-fMRI) to analyze regional homogeneity (ReHo), functional connectivity (FC), and network topology. Partial correlations assessed the association between neuroimaging alterations and clinical improvements. RESULTS: The tDCS group showed significantly greater improvements in MoCA scores (tDCS: 5.74 ± 2.76 vs. sham: 2.69 ± 2.69; t = 4.799, p < 0.001) as well as in attention and memory domains compared to the sham group. The rs-fMRI changes included increased ReHo in the right middle temporal gyrus (MTG) and the left inferior frontal gyrus (IFG), and reduced FC between the right MTG-left superior frontal gyrus and left IFG-cerebellum (p < 0.05, FWE-corrected). Additionally, small-worldness and global efficiency increased (p < 0.05) with these alterations correlating with clinical recovery. Adverse events were rare and self-limiting. CONCLUSION: Dual-tDCS over bilateral DLPFC safely improves cognitive recovery in PSCI. These clinical gains are associated with rs-fMRI alterations, specifically in regional synchronization, inter-regional connectivity, and global topology, which suggest a potential biomarker for monitoring tDCS efficacy, offering a rationale for precision neuromodulation in stroke rehabilitation.

Humans↗

PubMed1979

Effects of an enkephalin analog on complex learning in the rhesus monkey.

Facilitation of the learning of a discrimination reversal task for a reward of food was found in rhesus monkeys after subcutaneous administration of a potent pentafluorinated enkephalin analog. (D-Ala2)-F5-Phe4-enkephalin-NH2. General activity, short-term memory, startle, and analgesia, however, were not significantly affected. In a within-subject design, each of 6 monkeys (3 males and 3 females) received each of 5 doses of the enkephalin analog (0.1, 1, 10, 100, and 1,000 microgram/kg). One daily injection was made for 7 consecutive days, including pre- and posttests on the first and last days with the diluent control. The enkephalin doses, with the exception of the 0.1 microgram/kg level, produced significantly faster learning than the diluent. Some sex differences were suggested by the data, but these effects are difficult to interpret. The results suggest that relatively small amounts of this analog given systematically can exert a reliable effect on a complex behavior such as reversal learning at doses devoid of opiate effects, due perhaps to enhanced cognitive flexibility rather than improvement in short-term memory or association formation.

Analgesia↗

PubMed2026

Post-intervention effectiveness of a computerized personalized cognitive stimulation program adapted according to cognitive reserve in older adults without cognitive impairment in Primary Care: A randomized clinical trial.

BACKGROUND: Cognitive reserve may influence responsiveness to cognitive interventions, yet it is rarely used to tailor computerized stimulation. OBJECTIVE: To evaluate the effectiveness of a computerized cognitive stimulation program personalized according to cognitive reserve on cognition, reserve-related activities, and digital competence in community-dwelling older adults without cognitive impairment in Primary Care. METHODS: In this randomized clinical trial, 102 adults aged ≥65 years with normal cognitive performance were recruited from three primary care centers in Zaragoza, Spain, and stratified by cognitive reserve level before random allocation to intervention or control. The intervention comprised digital literacy sessions followed by 8 weeks of home-based computerized cognitive stimulation tailored to participants' cognitive reserve profiles and life history. Controls received a single group-based health education session focused on maintaining everyday cognitive activity. Outcomes were assessed at baseline and post-intervention using global cognition (MEC-35), the Cognitive Reserve Questionnaire, the Mobile Device Proficiency Questionnaire-16, and domain-specific neuropsychological tests. A total of 100 participants completed the final evaluation and were included in complete-case analyses. RESULTS: Compared with controls, the intervention group showed greater adjusted post-intervention improvements in global cognition (MEC-35 between-group difference: 1.8 points) and several cognitive measures, including temporal orientation, calculation, attention, praxis, verbal fluency, processing speed, executive functions, and verbal learning. CRQ scores and digital competence also improved, with small-to-large effect sizes. CONCLUSIONS: A computerized cognitive stimulation program adapted according to cognitive reserve appears feasible in Primary Care and may improve cognition, engagement in reserve-related activities, and digital competence in older adults without cognitive impairment.

Humans↗

PubMed2026

Effectiveness of psychosocial and lifestyle interventions in promoting behaviour change and improving cognitive outcomes in older people with memory concerns: A systematic review.

BACKGROUND: Older adults with mild cognitive impairment or subjective cognitive decline have a greater dementia risk, particularly those from minority ethnic and socioeconomically disadvantaged backgrounds. Psychosocial and lifestyle interventions targeting modifiable risk factors offer hope for reducing risk, yet behavioural mechanisms remain unclear. This systematic review examines these mechanisms and associated outcomes. METHOD: We searched PubMed, Embase (Ovid), PsycINFO (Ovid), Web of Science, and Scopus for randomised control trials testing interventions that aimed to improve lifestyle and cognition in older adults with memory concerns. We explored behavioural mechanisms using the COM-B model and synthesised intervention effectiveness, overall and within underserved groups. We prioritised lower risk of bias studies. RESULTS: 26 studies described 23 randomised controlled trials (14 multidomain, 9 single domain interventions). Certainty of evidence that behaviour change was associated with cognition was low. Moderate-certainty evidence indicated that interventions providing a socially supportive environment and combining nutritional education and counselling for 6 + months improved diet. Physical activity improved primarily in interventions incorporating education, structured training, and enablement strategies (e.g., tailored programmes, providing tools). Interventions simultaneously targeting capability, opportunity and motivation showed greater overall effectiveness. Few studies recorded ethnicity (13%) or sociodemographic status (9%), and none explored their impact. CONCLUSIONS: Non-pharmacological interventions can help this population improve their lifestyles if they feel capable, equipped and motivated, highlighting the value of careful design and implementation. There is scarce evidence on how these interventions work for underserved populations. Future research should explore this to inform tailored interventions and develop equitable dementia prevention strategies.

Humans↗

PubMed2026

Sustained cognitive and functional effects of pro-cognitive interventions for bipolar disorder: A systematic review of randomised controlled trials.

A substantial proportion of individuals with bipolar disorder (BD) experience considerable cognitive deficits. Existing systematic reviews have evaluated the efficacy of pro-cognitive interventions in BD, but have not established whether any cognitive benefits translate into functional improvements, with evidence for sustained functional effects remaining limited. A systematic search was conducted on MEDLINE, EMBASE, PsycINFO and Cochrane Library from inception until 21 May 2026. Eligible studies were randomised controlled trials (RCTs) in BD reporting cognitive or functional outcomes at three or more months following a pro-cognitive intervention, or examining the translation of cognitive benefits into improvements in functional outcomes at any timepoint. Seven unique RCTs plus three secondary analyses of these trials (n = 615) met the inclusion criteria. Approximately 13% (7/55) of RCTs identified in the search of pro-cognitive interventions in adult BD assessed cognitive or functional outcomes at least 3 months after treatment end. Of the seven unique RCTs, most evaluated cognitive remediation (CR; k = 4). The average follow-up length was 4 months (range: 3-6 months). Three of the four RCTs examining CR reported cognitive benefits at 3 to 6 months, whereas only one CR RCT found consistent functional effects at 3 months. Evidence on the translation of cognitive benefits to functional improvements is scarce and inconsistent. Most trials examining pro-cognitive interventions do not examine whether potential benefits are sustained or whether they translate into improvements in real-world functioning. CR appears to be a promising intervention for achieving durable cognitive gains in BD, although evidence for sustained effects of other interventions is limited.

Humans↗

PubMed2026

Effect of intraoperative 40-hz gamma-frequency auditory stimulation on postoperative delirium in older adults undergoing major surgery: a randomized clinical trial protocol.

INTRODUCTION: Postoperative delirium (POD) is a common and clinically significant complication among older adults undergoing major surgery under general anesthesia. Gamma-frequency (40-Hz) auditory stimulation has demonstrated potential neuroprotective and cognition-enhancing effects, suggesting a plausible role in perioperative delirium prevention. However, direct clinical evidence supporting intraoperative 40-Hz auditory stimulation in reducing POD remains limited, warranting rigorous evaluation in a randomized trial. PATIENTS AND METHODS: This prospective, parallel-group, randomized controlled trial will enroll 550 older adults scheduled for major noncardiac, nonneurosurgical surgery under general anesthesia. Participants will be randomized in a 1:1 ratio to either the active stimulation group, receiving intraoperative 40-Hz gamma-frequency auditory stimulation delivered via headphones for 2 h following successful anesthesia induction, or the sham stimulation group, wearing headphones without active auditory output. The primary outcome is the incidence of POD on postoperative day 1 though 3, assessed using the Confusion Assessment Method (CAM) or the CAM for the ICU (CAM-ICU). Secondary outcomes include POD severity, sleep quality, pain scores, analgesic consumption, the incidence of postoperative nausea and vomiting (PONV), rescue antiemetic use, duration of post-anesthesia care unit (PACU) stay, length of hospital stay, quality of postoperative recovery, incidence of perioperative adverse events; postoperative morbidity, health-related quality of life, and all-cause 30-day mortality. DISCUSSION: This trial will determine whether intraoperative 40-Hz gamma-frequency auditory stimulation reduces the incidence of POD among older adults undergoing major surgery under general anesthesia. If efficacious, this noninvasive intervention could constitute a feasible perioperative strategy to mitigate delirium risk and enhance postoperative recovery. CLINICAL TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR2500115156).

Humans↗

PubMed1976

Focus on maternal behavior in infant intervention.

A six-stage maternal behavior progression is outlined, and its use as a schema for the assessment of parental behavior in parent-infant interaction is described. This approach focuses on parent-infant interaction, rather than the teaching of infant skills, as a basis for enhancing cognitive and affective development of the child. Use of the schema is illustrated in two cases from an intervention program for high-risk infants.

Behavior Therapy↗

PubMed2026

The asymmetry of working memory training transfer: A systematic review and meta-analysis.

Working memory (WM) training is widely used to enhance cognitive performance; however, its transfer to untrained tasks remains controversial. Traditional theories emphasize task similarity as the primary determinant of training transfer, but they cannot fully explain emerging evidence of asymmetric transfer across tasks. Two directional transfer hypotheses are proposed here to explain this asymmetry: the resource-based transfer advantage hypothesis predicts stronger transfer from more to less cognitively demanding tasks, whereas the ability-based transfer advantage hypothesis predicts stronger transfer from tasks engaging broader task-general abilities to tasks engaging task-specific narrower abilities. The contrast between span and updating paradigms provides an informative framework for distinguishing these accounts, because updating tasks are generally more cognitively demanding, whereas span tasks involve broader abilities. Accordingly, we conducted a three-level meta-analysis of 55 studies (208 effect sizes; N = 3,492). The results showed that updating training transferred reliably to span tasks (g = 0.176, p < .001), whereas span training did not reliably transfer to updating tasks (g = 0.048, p = .453), supporting the resource-based account. This advantage of updating training also extended to non-WM outcomes and was more pronounced at lower training doses, in non-adult samples, and with verbal stimuli. Together, these findings extend WM transfer theory beyond task similarity by highlighting the importance of cognitive demand and offer guidance for WM training design.

Humans↗

PubMed2026

Game changer? Cognitive-motor effects of VR exergaming compared to video-based training.

BACKGROUND/OBJECTIVE: Virtual reality (VR) exergaming enhances several cognitive domains through multisensory engagement. Acute cognitive benefits of VR are established, but evidence for direct comparisons with non-immersive controls is limited. This study aimed to determine whether VR exercise provides additional cognitive and cognitive-motor benefits beyond a matched non-immersive active stick-fight video (SFV) intervention, and whether effects persist after training. METHODS: In this randomized quasi-experimental study, N = 55 healthy adults (VR: n = 30; SFV: n = 25; 25.5 ± 7.1 years; 41.8% female) completed an 8-week program (2 × 30 min/week), of VR or SFV matched in movement patterns, frequency, intensity and duration. Measurements included reaction time (RT), Stroop Test (versions 1-3), Letter Cancellation Test (LCT), Trail Making Test (TMT), Trail Walking Test (TWT) and Fitts task (difficulty level 1-4). Data were analyzed using mixed-design ANOVAs. RESULTS: Improvements were observed in Stroop reading (F(1,53) = 14.84, p < .001, η2 = 0.219), Stroop inhibition (F(1,53) = 10.99, p = .002, η2 = 0.172), and LCT (F(1,53) = 4.57, p = .037, η2 = 0.079). A time × group interaction was found for TMT (F(1,53) = 6.55, p = .031, η2 = 0.110), indicating greater changes following VR training. Both groups improved cognitive-motor performance (TWT: F(1,25) = 55.32, p < .001, η2 = 0.689; Fitts3: F(1,53) = 44.97, p < .001, η2 = 0.459), with greater gains for VR in Fitts3 (p = .006). CONCLUSION(S): Eight weeks of VR and SFV enhanced cognitive and cognitive-motor performance. VR provided domain-specific advantages in executive function, but these effects were not uniformly persistent. SFV sustained more improvements in real-world-relevant cognitive-motor tasks.

Humans↗

PubMed2026

Efficacy and Safety of Psychedelic Microdosing on Psychological Outcomes in Healthy Adults: A Systematic Review and Meta-analysis.

BACKGROUND: Psychedelic microdosing has gained increasing popularity for enhancing mood and cognition, yet its effects on psychological outcomes in healthy adults remain unclear. We aim to evaluate the efficacy and safety of psychedelic microdosing on psychological outcomes in healthy/non-clinical adult population. METHODS: This review was registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD420251035294). We searched Embase, MEDLINE, and PsycINFO from inception to February 2026 for original studies in healthy adults using sub-hallucinogenic psychedelic doses on separate days. We included randomized studies, nonrandomized prospective studies, cross-sectional studies, and observational longitudinal designs and stratified meta-analyses by design. Random-effects models were used; safety in randomized controlled trials (RCTs) was pooled as risk differences (RDs). Risk of bias was assessed using the Joanna Briggs Institute (JBI) critical appraisal tools appropriate for each study design. RESULTS: 24 studies (3,681 participants) met inclusion criteria, 6 contributed to meta-analyses. RCTs of psilocybin and LSD microdosing showed subjective and neurophysiological effects but minimal impact on cognition, creativity, or sustained mood. Psilocybin altered EEG and speech with little behavioral change, while LSD caused transient mood and minor physiological effects without lasting cognitive or personality benefits. Observational studies indicated mood and personality improvements, likely influenced by expectancy or lifestyle factors. Meta-analyses included two parallel RCTs (3 comparisons; n = 117) and three non-RCT studies (n = 1,013). Adverse event analyses included two RCTs (4 comparisons; n = 109). RCTs showed no clear evidence of immediate symptom reduction: depressive symptoms (SMD = -0.19; 95% CI -0.56, 0.19; I2 = 0%), anxiety (SMD = -0.20; 95% CI -1.11, 0.71; I2 = 82.3%),and stress (SMD = 0.02; 95% CI -0.39, 0.43; I2 = 0%). Non-RCT within-arm estimates were imprecise and heterogeneous for depressive symptoms (SMCC -0.33; 95% CI -0.75, 0.08) and anxiety (SMCC -0.29; 95% CI-0.84, 0.26). Exploratory pooling across all designs suggested decreases in depressive symptoms and stress, while anxiety remained uncertain. Adverse event risks were similar between treatment and control. CONCLUSIONS: Microdosing does not show consistent immediate benefits for depressive, anxiety, or stress symptoms in healthy adults, and evidence from RCTs remains inconclusive. Although improvements were observed in some studies, these effects were not significantly different from placebo. Larger, well-designed RCTs are needed to clarify the efficacy and safety of psychedelic microdosing beyond placebo.

Humans↗

PubMed2026

Subacute and long-term changes in cognitive functioning after administration of classic psychedelics, MDMA and ketamine: A systematic review of clinical and preclinical evidence.

Psychedelic agents induce a window of heightened neuroplasticity that extends beyond acute intoxication, during which neural circuits are more amenable to change. This period may facilitate changes in cognition relevant to the treatment of psychiatric disorders. This systematic review synthesised clinical and preclinical evidence of subacute and long-term (≥1 day) effects of classic and non-classic psychedelics on cognition. MEDLINE, EMBASE, APA PsycInfo and Web of Science were searched to identify human and animal studies investigating psychedelics and cognition (executive function, attention, decision-making). Sixty-seven (47 clinical, 20 preclinical) articles met inclusion criteria. Psilocybin demonstrated the most consistent evidence of subacute and longer-term cognitive improvement, particularly in cognitive flexibility and attention. Ketamine showed enhancement across cognitive domains, although findings were heterogeneous. LSD and DMT showed no consistent subacute changes, while MDMA was associated with transient cognitive impairments that resolved within days. Risk of bias assessments revealed selective outcome reporting, poor reporting of missing data and inadequate methodological detail, limiting the confidence of findings. Current evidence provides preliminary support for subacute changes in cognition following administration of select psychedelic agents. Cognitive improvements were more frequently seen in psychiatric populations than healthy subjects, which may reflect a remediation of existing cognitive deficit rather than enhancement above normal functioning. Adequately powered, controlled studies with standardised reporting of cognitive outcomes are required to determine the magnitude, durability and clinical relevance of psychedelic-associated cognitive change.

Hallucinogens↗