The Relationship between Serum Brain-Derived Neurotrophic Level and Neurocognitive Functions in Chronic Methamphetamine Users

Objectives: Methamphetamine (METH) is a highly addictive psychostimulant that has neurotoxic effects on the brain. Given evidence indicating that brain-derived neurotrophic factor (BDNF) is associated with addictive behaviors, this study aimed to investigate the serum level of BDNF and cognitive functions in chronic METH users and healthy subjects. <br><br>Methods: Thirty-seven chronic METH users and 37 healthy controls were recruited in this study. Cognitive functioning including executive functions and working memory were assessed using the Wisconsin Card Sorting Test (WCST) and Wechsler Memory Scale (WMS), respectively. <br><br>Results: The levels of serum BDNF were also examined using an enzyme-linked immunosorbent assay kit. Current results showed that METH users had significant impairment in executive function and working memory compared to healthy subjects. Also, the serum BDNF concentrations of METH users were significantly higher than the healthy subjects (42± 13.34 ng/ml vs. 24 ± 7 ng/ml). BDNF concentration was significantly correlated with duration (r=0.37, p=0.02) and dose of METH use (r=0.35, p=0.02). Besides, the BDNF level was not associated with any subscales of WCST and WMS. <br><br>Conclusion: These results provide further evidence regarding the role of increased serum BDNF level in the pathophysiology of METH addiction and protective response against the neurotoxicity of METH. Besides, these findings suggest that increased serum BDNF levels are not related to cognitive impairment in METH users.<br><br>Funding Information: This study was funded by the Iran University of Medical Sciences (Grant Number: 97-01-211-33651) and Cognitive Science and Technology Council of Iran (Grant Number: <br>7298).<br><br>Declaration of Interests: No conflict declared.<br><br>Ethics Approval Statement: This study was approved by the institutional review board at the Iran University of Medical Sciences (IR.IUMS.REC.1398.046); also, all human experimental protocols were in line with the Declaration of Helsinki. All recruited participants were provided with written informed consent after being fully informed of the benefits and potential risks of participating in this study.