RESUMEN
Background: The aim of this cross-sectional study was to investigate the prevalence of sleep disturbance and its possible associated factors among Iranian medical students. Additionally, a national meta-analysis was conducted to provide a comprehensive overview of sleep disturbance in this population. Methods: A sample of medical students from Guilan University of Medical Sciences, Iran was included in the study. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep disturbance. Demographic and lifestyle factors, as well as academic performance, were collected through a self-administered questionnaire. The data collected from this study were combined with existing studies through a meta-analysis to estimate the overall prevalence of sleep disturbance among Iranian medical students using the random effects model. Results: A total of 249 medical students participated in the study. The prevalence of sleep disturbance among Guilan University of Medical Sciences medical students was found to be 71.1%. A significant difference was observed in total PSQI means regarding medical students' residency (p < 0.001) and their duration of sleep in the last 24 h (p = 0.006). The national prevalence of sleep disturbances was 59% (95% CI: [51%-66%], I2 = 97%). Conclusion: Sleep disturbance is highly prevalent among Iranian medical students, with various factors contributing to its occurrence. The findings of this study highlight the need for interventions and strategies to improve sleep quality and overall well-being among this population. The national meta-analysis provides valuable insights into the overall burden of sleep disturbance among Iranian medical students and can serve as a reference for future studies and public health initiatives targeting this issue.
RESUMEN
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.