Introduction: Burnout syndrome, long described as an “occupational phenomenon”, now affects 15–20% of the general workforce and more than 50% of clinicians, teachers, social-care staff and first responders. Its precise nosological standing remains disputed. We conducted a mechanistic review of electroencephalography (EEG) studies to determine whether burnout is accompanied by reproducible brain-function alterations that justify disease-level classification. Methods: Following PRISMA-adapted guidelines, two independent reviewers searched PubMed/MEDLINE, Scopus, Google Scholar, Cochrane Library and reference lists (January 1980–May 2025) using combinations of “burnout,” “EEG”, “electroencephalography” and “event-related potential.” Only English-language clinical investigations were eligible. Eighteen studies (n = 2194 participants) met the inclusion criteria. Data were synthesised across three domains: resting-state spectra/connectivity, event-related potentials (ERPs) and longitudinal change. Results: Resting EEG consistently showed (i) a 0.4–0.6 Hz slowing of individual-alpha frequency, (ii) 20–35% global alpha-power reduction and (iii) fragmentation of high-alpha (11–13 Hz) fronto-parietal coherence, with stage- and sex-dependent modulation. ERP paradigms revealed a distinctive “alarm-heavy/evaluation-poor” profile; enlarged N2 and ERN components signalled hyper-reactive conflict and error detection, whereas P3b, Pe, reward-P3 and late CNV amplitudes were attenuated by 25–50%, indicating depleted evaluative and preparatory resources. Feedback processing showed intact or heightened FRN but blunted FRP, and affective tasks demonstrated threat-biassed P3a latency shifts alongside dampened VPP/EPN to positive cues. These alterations persisted in longitudinal cohorts yet normalised after recovery, supporting trait-plus-state dynamics. The electrophysiological fingerprint differed from major depression (no frontal-alpha asymmetry, opposite connectivity pattern). Conclusions: Across paradigms, burnout exhibits a coherent neurophysiological signature comparable in magnitude to established psychiatric disorders, refuting its current classification as a non-disease. Objective EEG markers can complement symptom scales for earlier diagnosis, treatment monitoring and public-health surveillance. Recognising burnout as a clinical disorder—and funding prevention and care accordingly—is medically justified and economically imperative.

Introduction: Chewing gum is a widespread, seemingly mundane behaviour that has been linked to diverse benefits such as improved cognitive performance, reduced stress, and enhanced alertness. While animal and human research indicate that mastication engages extensive sensorimotor networks and may also modulate higher-order cognitive and emotional processes, questions remain about the specific neural mechanisms involved. This review combines findings from neuroimaging studies—including fMRI, fNIRS, and EEG—that investigate how chewing gum alters brain activity in humans. Methods: Using a targeted search strategy, we screened the major databases (PubMed/Medline, Scopus, ResearchGate, Google Scholar, and Cochrane) from January 1980 to March 2025 for clinical studies published in English. Eligible studies explicitly measured brain activity during gum chewing using EEG, fNIRS, or fMRI. Results: After a title/abstract screening and a full-text review, thirty-two studies met the inclusion criteria for this review: 15 utilising fMRI, 10 using fNIRS, 2 using both fNIRS and EEG, and 5 employing EEG. Overall, the fMRI investigations consistently reported strong activation in bilateral motor and somatosensory cortices, the supplementary motor area, the insula, the cerebellum, and the thalamus, during gum chewing, with several studies also noting involvement of higher-order prefrontal and cingulate regions, particularly under stress conditions or when participants chewed flavoured gum. The fNIRS findings indicated that chewing gum increased oxygenated haemoglobin in the prefrontal cortex, reflecting heightened cortical blood flow; these effects were often amplified when the gum was flavoured or when participants were exposed to stressful stimuli, suggesting that both sensory and emotional variables can influence chewing-related cortical responses. Finally, the EEG studies documented transient increases in alpha and beta wave power during gum chewing, particularly when flavoured gum was used, and reported short-lived enhancements in vigilance or alertness, which tended to subside soon after participants ceased chewing. Conclusions: Neuroimaging data indicate that chewing gum reliably engages broad sensorimotor circuits while also influencing regions tied to attention, stress regulation, and possibly memory. Although these effects are often short-lived, the range of outcomes—from changes in cortical oxygenation to shifts in EEG power—underscores chewing gum’s capacity to modulate brain function beyond simple oral motor control. However, at this time, the neural changes associated with gum chewing cannot be directly linked to the positive behavioural and functional outcomes observed in studies that measure these effects without the use of neuroimaging techniques. Future research should address longer-term impacts, refine methods to isolate flavour or stress variables, and explore potential therapeutic applications for mastication-based interventions.

Transcranial direct current stimulation (tDCS) can modulate cortical excitability in a polarity-specific manner, yet identical protocols often produce inconsistent outcomes across sessions or individuals. This narrative review proposes that much of this variability arises from the brain’s intrinsic temporal landscape. Integrating evidence from chronobiology, sleep research, and non-invasive brain stimulation, we argue that tDCS produces reliable, polarity-specific after-effects only within a circadian–homeostatic “window of efficacy”. On the circadian (Process C) axis, intrinsic alertness, membrane depolarisation, and glutamatergic gain rise in the late biological morning and early evening, whereas pre-dawn phases are marked by reduced excitability and heightened inhibition. On the homeostatic (Process S) axis, consolidated sleep renormalises synaptic weights, widening the capacity for further potentiation, whereas prolonged wakefulness saturates plasticity and can even reverse the usual anodal/cathodal polarity rules. Human stimulation studies mirror this two-process fingerprint: sleep deprivation abolishes anodal long-term-potentiation-like effects and converts cathodal inhibition into facilitation, while stimulating at each participant’s chronotype-aligned (phase-aligned) peak time amplifies and prolongs after-effects even under equal sleep pressure. From these observations we derive practical recommendations: (i) schedule excitatory tDCS after restorative sleep and near the individual wake-maintenance zone; (ii) avoid sessions at high sleep pressure or circadian troughs; (iii) log melatonin phase, chronotype, recent sleep and, where feasible, core temperature; and (iv) consider mild pre-heating or time-restricted feeding as physiological primers. By viewing Borbély’s two-process model and allied metabolic clocks as adjustable knobs for plasticity engineering, this review provides a conceptual scaffold for personalised, time-sensitive tDCS protocols that could improve reproducibility in research and therapeutic gain in the clinic.

Although empirical reports draw attention to the pathological aspects of the functioning of the homeless, recent studies show the benefits related to the elevating roles of different positive phenomena in coping with difficulties for this group of people. The main goal was to verify whether there is a direct relationship between religiosity and gratitude among the homeless, and whether this association is moderated by the reported help-seeking since both religiosity and gratitude seem to play an important role in homeless people’s lives. In total, 189 homeless persons participated in the study. Their mean age was M = 56.55 (SD = 12.39; range = 27–86). Most respondents were men (n = 119; 63%). The Scale of Religious Attitude Intensity and the Gratitude Questionnaire were used. The outcomes presented a statistically significant positive correlation between religious attitude and gratitude (r = 0.326***, p = 0.001). Help-seeking played a moderatory role in this relationship. Therefore, it can be assumed that the relationship between religiosity attitude intensity and dispositional gratitude is stronger when homeless persons seek specific help from other people or institutions compared to when they do not look for assistance. Homeless people, overcoming their limitations by actively asking for help, can strengthen their bonds with God (faith, religiosity) and with others (dispositional gratitude).

Introduction: Caffeine is a widely consumed adenosine receptor antagonist with well-documented effects on arousal and performance, but its time-resolved neurophysiological signature across stages of information processing remains fragmented across event-related potential (ERP) paradigms. Objectives: This systematic and mechanistic review aimed to (i) identify and catalog human ERP studies testing caffeine effects, (ii) synthesize findings by task domain and ERP component family, and (iii) evaluate moderators including dose, timing, abstinence/withdrawal control, sleep status, and habitual use. Methods: Following PRISMA 2020 and PRISMA-S, we searched multiple databases (PubMed/MEDLINE, Embase, APA PsycINFO, Web of Science Core Collection, Scopus, IEEE Xplore, and Cochrane Central Register of Controlled Trials) from inception to 28 November 2025 and conducted a structured narrative synthesis using SWiM (Synthesis Without Meta-analysis, no prespecified quantitative pooling). Risk of bias was assessed using RoB-2 (Risk of Bias 2, including crossover extension) and ROBINS-I (Risk Of Bias In Nonrandomized Studies of Interventions). Of 761 records, 63 controlled human studies met the inclusion criteria. The evidence most consistently supported stage- and context-dependent modulation. Within the P3 family, target-related P3b/P300 latency was frequently shortened, or fatigue-related slowing was prevented, often without parallel increases in amplitude. P300 amplitude findings were mixed and context-dependent: amplitude was often unchanged in rested or low-demand paradigms, but increased or was restored when caffeine counteracted fatigue, sleep loss, sustained attention demands, or high workload. Preparatory activity (CNV/slow negativity) showed selective effects, while early sensory components were comparatively stable in many paradigms; higher doses (approximately 200–400 mg) were associated with weaker early auditory sensory gating in some studies. Conclusions: Across heterogeneous paradigms, caffeine was associated with context-dependent ERP changes rather than a uniform amplification of ERP amplitudes. The most consistent pattern was shorter or preserved latency of late positive ERP components, particularly in tasks requiring stimulus evaluation or target detection. In some fatigue, sleep deprivation, sustained attention, or high-demand paradigms, caffeine was also associated with larger or restored P300/P3b amplitudes. These findings are compatible with state-dependent changes in attentional engagement or stimulus evaluation, but mechanistic interpretation remains limited by heterogeneity in task paradigms, ERP definitions, dosing, abstinence procedures, and participant caffeine use profiles. Methodological heterogeneity, small samples, inconsistent control of habitual use and withdrawal, and the predominance of healthy young adult samples limit generalizability, particularly to children, older adults, clinical populations, and long-term high-dose caffeine users.

Interest in classical psychedelics as potential treatments for ADHD has grown alongside broader psychiatric psychedelic research, but ADHD-specific evidence remains limited. This systematic review examined prospective and experimental studies on whether classical psychedelics, including microdosing-like use and retreat-based exposure, are associated with changes in adult ADHD symptoms and related functioning. A PRISMA-guided systematic review was conducted using a PECO/PICO framework focused on adults (≥18 years) with diagnosed ADHD and/or elevated ADHD symptomatology who were exposed to a classical psychedelic and assessed prospectively with quantitative ADHD outcomes. Major databases were searched, with reference screening and targeted checks for recent or registered trials. Risk of bias was assessed using RoB 2 for the RCT and ROBINS-I for non-randomized studies. Because of heterogeneity and the small number of studies, findings were synthesized narratively. Five studies met the inclusion criteria. Five prospective/experimental studies were included: three naturalistic online microdosing cohorts, one randomized double-blind placebo-controlled phase 2A trial of low-dose LSD, and one pre-post ayahuasca retreat pilot. In uncontrolled naturalistic microdosing studies, participants reported short-term reductions in ADHD symptom ratings together with improvements in well-being and affect-related functioning; however, these studies were highly vulnerable to self-selection, expectancy, attrition, and non-standardized exposure. In contrast, the only randomized placebo-controlled ADHD trial found improvement in both LSD and placebo groups, with no statistically significant advantage for LSD on clinician-rated or self-reported ADHD outcomes. Objective cognitive findings were limited and inconsistent, and safety data outside the supervised trial context were sparse. Naturalistic studies provide, at most, low-certainty signals of perceived short-term improvement, but the strongest controlled evidence does not demonstrate drug-specific efficacy of repeated low-dose LSD for core ADHD symptoms. Current evidence therefore does not allow separation of pharmacological effects from expectancy, setting, self-monitoring, and broader experiential/contextual influences, and is insufficient to support psychedelics as an evidence-based treatment for ADHD.