Objective: Post-traumatic stress disorder (PTSD) is a serious mental health challenge that usually lacks effective responses to conventional therapies. High-definition transcranial alternating current stimulation (HD-tACS) is gaining attention as a potential therapeutic approach for neuropsychiatric disorders. This study aimed to investigate the effects of 1-Hz tACS on PTSD symptoms. Methods: A randomized controlled trial involving 40 PTSD patients was designed. Patients were randomly divided into sham and real stimulation groups and underwent 10 HD-tACS sessions. We used 1-Hz HD-tACS with the central anode positioned at T8 and the ring cathodes at P8, C4, F8 and EX10 (targeting right lateral temporal cortex). Clinical symptoms of patients were evaluated through the PTSD Checklist for DSM-5 (PCL-5). Also, we measured salivary cortisol levels and serum brain-derived neurotrophic factor (BDNF) levels before and after treatment. Results: The real stimulation resulted in a more significant reduction in PTSD symptoms as measured by the mean PCL-5 score (56.25 ± 12.13 to 39.40 ± 13.91) compared to the sham stimulation (p ＜ 0.05). The mean salivary cortisol level increased significantly in the real stimulation group (0.053 ± 0.04 μg/dl to 0.10 ± 0.07 μg/dl) compared to the sham (p ＜ 0.001). In contrast, serum BDNF levels showed no significant changes in either group. Conclusion Preliminary findings suggest that HD-tACS in delta band can significantly alleviate PTSD symptoms, indicating its potential as a therapeutic intervention for PTSD.

Objective: Brain-derived neurotrophic factor (BDNF) and high sensitive C-reactive protein (hs-CRP) have been reported to play roles in depression and bipolar disorder (BD). However, the probable discriminatory properties of these biologic markers are less investigated. We aimed to assess the serum BDNF and hs-CRP levels among Iranian patients with major depressive disorder (MDD) and BD during a depressive episode and investigate the optimum cut-off point for differential diagnosis of BD and MDD. Methods: We recruited 30 patients with MDD, 30 with BD in depressive mood and 30 healthy comparators. Blood sample was taken from each participant to measure BDNF and hs-CRP levels. We also used receiver operating characteristic (ROC) curve analysis to find an optimal cut-off point for differentiating MDD from BD according to pre-defined variables. Results: The mean age of total study population was 37.3 ± 5.0 years (males: 49%). BDNF was significantly lower in patients with BD, followed by MDD subjects and healthy controls 541.0 ± 601.0 pg/ml vs. 809.5 ± 433.3 pg/ml vs. 1,482.1 ± 519.8, respectively, p ＜ 0.001). The area under curve of ROC curve analysis for BD versus MDD was 0.704 (95% confidence interval: 0.564−0.844, p = 0.007). We also found that the BDNF cut-off value of 504 could appropriately distinguished BD from MDD (sensitivity: 73%, specificity: 70%). No significant association were identified in terms of hs-CRP levels. Conclusion Patients suffering from BD had lowest BDNF levels compared to MDD or healthy adults and this biomarker could play a practical role differentiating MDD from BD. Several studies are required confirming our outcomes.