Effect of cannabis use on blood levels of brain‐derived neurotrophic factor (BDNF) and nerve growth factor (NGF): A systematic review and meta‐analysis

Abstract Background The impact of cannabis uses on blood levels of brain‐derived neurotrophic factor (BDNF) and nerve growth factor (NGF) remains uncertain, with conflicting findings reported in the literature. BDNF and NGF both are essential proteins for neuron's growth, and their dysregulation is seen in various mental disorders. This study aims to evaluate the relationship between cannabis usage and BDNF and NGF levels due to their potential implications for mental health. Methods A comprehensive search of electronic databases was performed using appropriate MeSH terms and keywords. Inclusion criteria comprised human studies investigating the relationship between cannabis use and BDNF and NGF levels. Results A total of 11 studies met the inclusion criteria and were included. The pooled analysis revealed a nonsignificant association between cannabis use and dysregulated blood levels of BDNF (random‐effects model, standardized mean differences [SMD] = .26, 95% CI −.34 to .76, p = .40). The results of our subgroup analysis based on BDNF source showed a nonsignificant between‐group difference. For NGF levels, four studies were included, the pooled analysis revealed a nonsignificant association between cannabis use and dysregulated blood levels of NGF (random‐effects model, SMD = −.60, 95% CI −1.43 to –.23, p = .16). In both analyses, high heterogeneity was observed among the included studies which is a notable limitation to current meta‐analysis. Conclusion This systematic review highlights the need for further research to elucidate the relationship between cannabis use and these neurotrophic factors. A better understanding of these associations can contribute to our knowledge of the neurobiological effects of cannabis and inform potential implications for mental health, cognitive function, and neurodegenerative disorders

Effect of alcohol on Brain-Derived Neurotrophic Factor (BDNF) blood levels: a systematic review and meta-analysis

Abstract Brain-Derived Neurotrophic Factor (BDNF) is a vital protein involved in neuronal development, survival, and plasticity. Alcohol consumption has been implicated in various neurocognitive deficits and neurodegenerative disorders. However, the impact of alcohol on BDNF blood levels remains unclear. This systematic review and meta-analysis aimed to investigate the effect of alcohol consumption on BDNF blood levels. A comprehensive search of electronic databases was conducted to identify relevant studies. Eligible studies were selected based on predefined inclusion criteria. Data extraction was performed, and methodological quality was assessed using appropriate tools. A meta-analysis was conducted to estimate the overall effect size of alcohol consumption on BDNF levels. A total of 25 studies met the inclusion criteria and were included in the final analysis. Alcohol use and BDNF blood levels were significantly correlated, according to the meta-analysis (p = 0.008). Overall, it was discovered that drinking alcohol significantly decreased BDNF levels (SMD: − 0.39; 95% CI: − 0.68 to − 0.10; I2: 93%). There was a non-significant trend suggesting that alcohol withdrawal might increase BDNF levels, with an SMD of 0.26 (95% CI: − 0.09 to 0.62; I2: 86%; p = 0.14). Subgroup analysis based on the source of BDNF demonstrated significant differences between the subgroups (p = 0.0008). No significant publication bias was observed. This study showed that alcohol consumption is associated with a significant decrease in BDNF blood levels. The findings suggest a negative impact of alcohol on BDNF levels regardless of alcohol dosage. Further studies are needed to strengthen the evidence and elucidate the underlying mechanisms

The global prevalence of depression, anxiety, and sleep disorder among patients coping with Post COVID-19 syndrome (long COVID): a systematic review and meta-analysis

Abstract Background Post COVID-19 syndrome, also known as "Long COVID," is a complex and multifaceted condition that affects individuals who have recovered from SARS-CoV-2 infection. This systematic review and meta-analysis aim to comprehensively assess the global prevalence of depression, anxiety, and sleep disorder in individuals coping with Post COVID-19 syndrome. Methods A rigorous search of electronic databases was conducted to identify original studies until 24 January 2023. The inclusion criteria comprised studies employing previously validated assessment tools for depression, anxiety, and sleep disorders, reporting prevalence rates, and encompassing patients of all age groups and geographical regions for subgroup analysis Random effects model was utilized for the meta-analysis. Meta-regression analysis was done. Results The pooled prevalence of depression and anxiety among patients coping with Post COVID-19 syndrome was estimated to be 23% (95% CI: 20%—26%; I2 = 99.9%) based on data from 143 studies with 7,782,124 participants and 132 studies with 9,320,687 participants, respectively. The pooled prevalence of sleep disorder among these patients, derived from 27 studies with 15,362 participants, was estimated to be 45% (95% CI: 37%—53%; I2 = 98.7%). Subgroup analyses based on geographical regions and assessment scales revealed significant variations in prevalence rates. Meta-regression analysis showed significant correlations between the prevalence and total sample size of studies, the age of participants, and the percentage of male participants. Publication bias was assessed using Doi plot visualization and the Peters test, revealing a potential source of publication bias for depression (p = 0.0085) and sleep disorder (p = 0.02). However, no evidence of publication bias was found for anxiety (p = 0.11). Conclusion This systematic review and meta-analysis demonstrate a considerable burden of mental health issues, including depression, anxiety, and sleep disorders, among individuals recovering from COVID-19. The findings emphasize the need for comprehensive mental health support and tailored interventions for patients experiencing persistent symptoms after COVID-19 recovery