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Recent evidence suggests that reduced peripheral levels of brain-derived neurotrophic factor (BDNF) may be involved in the pathophysiology of bipolar disorder (BD), although its relevance in young populations remains uncertain. This systematic review synthesized studies that evaluated serum BDNF levels in children and adolescents with BD, examining its potential as a risk marker. Following PRISMA 2020 guidelines and a protocol registered in PROSPERO, searches were conducted in the Cochrane, MEDLINE, SciELO, and Scopus databases. Studies including participants aged 0-19 years diagnosed with BD according to DSM criteria were included. Studies with mixed samples (adults, children and adolescents) without separate age-group analyses were excluded. After screening and eligibility assessment, seven studies were included. Five of them included a control group, from which a meta-analysis was performed. Moderate methodological heterogeneity was observed and corrected after sensitivity analysis, reinforcing the robustness of the findings, although no statistically significant difference in serum BDNF levels was found between patients with bipolar disorder and controls. Current evidence does not support BDNF as a diagnostic biomarker for pediatric BD. Future studies with greater sample power and methodological standardization are needed to clarify its role in the risk and course of early-onset bipolar disorder. Show less

Electroconvulsive therapy (ECT) proves to be an effective intervention in severe cases of major depressive disorder (MDD), especially when there is resistance to pharmacological treatment. The neurotrophic hypothesis proposes that an increase in brain-derived neurotrophic factor (BDNF) is one of the mechanisms responsible for the therapeutic response. The aim of this study is to investigate the effects of ECT on peripheral levels of BDNF, measured in serum and plasma, and analyze clinical outcomes associated with this intervention, as well as identify methodological variables that may influence findings. A systematic review and meta-analysis of studies published between 1995 and 2025 on the PubMed, Scopus and Web of Science databases were conducted, following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Studies of BDNF in serum (14) and plasma (6) were performed separately. Clinical effectiveness was evaluated according to average standardized differences in depression scores. Meta-regressions in the R software identified the impact of four moderators: type of ECT, number of sessions, type of anesthetic and the time blood sample was taken. ECT was associated with an increase in BDNF levels in both biological matrices, especially in studies with plasma (I Show less

Conflicting results on the association of the Using combinations of various key terms, articles in PubMed, Google Scholar, and Web of Science, written in English were collected until October 31, 2024. Data were extracted independently by two authors and analyzed using Review Manager 5.4. Fifteen studies that are compliant with the HWE, providing a total of 14,184 participants were included in this meta-analysis after applying predefined inclusion/exclusion criteria based on study design, DSM-based diagnosis, and availability of genotype counts. Most pooled models demonstrated low to moderate heterogeneity with significant associations in the recessive model only. In the subgroup analysis, a significant effect was observed in the PD-uncategorized cohort. The Our updated meta-analysis suggests that the Show less

Social context modulates stress physiology and resilience, yet preclinical rat paradigms vary widely in stressor type, timing of social exposure, contact modality, and endpoint definitions. We synthesized rat studies to quantify directional and, where feasible, standardized effect-size evidence for social buffering and to outline translational implications. PubMed, Scopus, and Web of Science were searched (2008-2025) for in vivo rat studies comparing conspecific (pair/group housing or conspecific presence) versus solitary conditions across validated stress and PTSD-like paradigms (e.g., fear conditioning/extinction, CUS/CMS, social defeat, predator threat). Data extraction and reporting followed PRISMA 2020 and SYRCLE guidance. Synthesis followed a two-tier approach: (i) all eligible contrasts were direction-coded as beneficial, neutral/mixed, or detrimental under conspecific conditions based strictly on reported statistical contrasts; and (ii) for domains with sufficient coded contrasts, the proportion of beneficial comparisons was estimated with exact binomial tests and 95% confidence intervals. Standardized mean-difference meta-analysis (Hedges' g; random-effects REML) was conducted only for predefined outcomes with adequate numerical reporting. Forty studies met inclusion criteria, yielding 89 extracted comparisons. Overall, 69/89 comparisons (≈78%) favored conspecific conditions. Domain-level directional syntheses supported predominance of beneficial outcomes for hormonal (0.72; 95% CI 0.50-1.00; p = 0.048) and neurotrophic/plasticity markers (0.89; 95% CI 0.57-1.00; p = 0.020), whereas inflammatory/oxidative outcomes were more variable (0.71; 95% CI 0.39-0.94; p = 0.227). For predefined behavioral endpoints with sufficient data, effect-size pooling showed a large reduction in conditioned fear (Hedges' g = -1.22 [-1.53; -0.91], p < 0.0001). Social buffering is robust at behavioral and neuroendocrine levels and often aligns with neurotrophic/plasticity markers, while peripheral immune/redox readouts are more context-dependent. Show less

Individuals with schizophrenia spectrum disorders experience impairments across multiple domains, including cognition, quality of life, and social functioning. Structured exercise interventions may improve these outcomes. We hypothesised that aerobic and combined (aerobic plus resistance) exercise programs would enhance cognitive function, reduce symptom severity, and improve well-being. A PRISMA-guided search of PubMed, EMBASE, PsycINFO, Web of Science, SciELO, and ClinicalTrials.gov (2009-2024) identified 17 randomized controlled trials. Standardized mean differences (SMDs) were pooled using a random-effects model. Subgroup analyses examined age and gender. Risk of bias was assessed using RoB 2, publication bias with Egger's test, and certainty of evidence through GRADE. Structured exercise produced a moderate-to-large improvement in overall well-being (SMD = 0.68; 95% CI: 0.43-0.93; p < .001). Significant benefits were also observed in cognition (SMD = 0.59), symptom severity (SMD = 0.71), quality of life (SMD = 0.60), and social functioning (SMD = 0.55). Age and gender moderated treatment effects, with the strongest benefits in males and individuals aged 36-45. Sensitivity analyses confirmed the robustness of results. Mechanistic evidence suggests that improvements may be mediated through increased brain-derived neurotrophic factor (BDNF) and reduced inflammatory signaling. Structured exercise is an effective adjunctive intervention for schizophrenia spectrum disorders, improving psychiatric and functional outcomes beyond standard care. Findings support the integration of personalized, scalable exercise programs within routine psychiatric treatment. Show less