Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation method that delivers 1-2 mA of current to the scalp. Several clinical studies have been conducted to confirm the therapeutic effect of major depressive disorder (MDD) patients with tDCS. Some studies have shown tDCS's antidepressant effect, while the others showed conflicting results in antidepressant effects. Our aim of this review is to understand the biological bases of tDCS's antidepressant effect and review the results of studies on tDCS's antidepressant effect. For the review and search process of MDD treatment using tDCS, the US National Library of Medicine search engine PubMed was used. In this review, we discuss the biological mechanism of tDCS's antidepressant effect and the existing published literature including meta-analysis, systematic review, control trial, open studies, and case reports of antidepressant effects and cognitive function improvement in patients with MDD are reviewed. We also discuss the appropriate tDCS protocol for MDD patients, factors predictive of response to tDCS treatment, the disadvantages of tDCS in MDD treatment, and side effects.

Objectives According to previous studies, the Chromogranin B (CHGB) gene could be an important candidate gene for schizophrenia which is located on chromosome 20p12.3. Some studies have linked the polymorphism in CHGB gene with the risk of schizophrenia. Meanwhile, smooth pursuit eye movement (SPEM) abnormality has been regarded as one of the most consistent endophenotype of schizophrenia. In this study, we investigated the association between the polymorphisms in CHGB gene and SPEM abnormality in Korean patients with schizophrenia. Methods We measured SPEM function in 24 Korean patients with schizophrenia (16 male, 8 female) and they were divided according to SPEM function into two groups, good and poor SPEM function groups. We also investigated genotypes of polymorphisms in CHGB gene in each group. A logistic regression analysis was performed to find the association between SPEM abnormality and the number of polymorphism. Results The natural logarithm value of signal/noise ratio (Ln S/N ratio) of good SPEM function group was $4.19{\pm}0.19$ and that of poor SPEM function group was $3.17{\pm}0.65$. In total, 15 single nucleotide polymorphisms of CHGB were identified and the genotypes were divided into C/C, C/R, and R/R. Statistical analysis revealed that two genetic variants (rs16991480, rs76791154) were associated with SPEM abnormality in schizophrenia (p = 0.004). Conclusions Despite the limitations including a small number of samples and lack of functional study, our results suggest that genetic variants of CHGB may be associated with SPEM abnormality and provide useful preliminary information for further study.nwhile, smooth pursuit eye movement (SPEM) abnormality has been regarded as one of the most consistent endophenotype of schizophrenia. In this study, we investigated the association between the polymorphisms in CHGB gene and SPEM abnormality in Korean patients with schizophrenia. MethodsZZWe measured SPEM function in 24 Korean patients with schizophrenia (16 male, 8 female) and they were divided according to SPEM function into two groups, good and poor SPEM function groups. We also investigated genotypes of polymorphisms in CHGB gene in each group. A logistic regression analysis was performed to find the association between SPEM abnormality and the number of polymorphism. ResultsZZThe natural logarithm value of signal/noise ratio (Ln S/N ratio) of good SPEM function group was $4.19{\pm}0.19$ and that of poor SPEM function group was $3.17{\pm}0.65$. In total, 15 single nucleotide polymorphisms of CHGB were identified and the genotypes were divided into C/C, C/R, and R/R. Statistical analysis revealed that two genetic variants (rs16991480, rs76791154) were associated with SPEM abnormality in schizophrenia (p = 0.004). ConclusionsZZDespite the limitations including a small number of samples and lack of functional study, our results suggest that genetic variants of CHGB may be associated with SPEM abnormality and provide useful preliminary information for further study.

Objectives This study aimed to investigate the relationship between depressive and anxiety symptoms and tardive dyskinesia (TD) and reveal the association of cognitive function and TD in patients with schizophrenia. Methods We recruited 30 schizophrenia patients with TD and 31 without TD from a national mental hospital in South Korea. To assess depressive and anxiety symptoms, the Beck Depression Inventory-II (BDI-II) and the Beck Anxiety Inventory (BAI) were conducted. Using the five-factor structure of the BDI-II and BAI, somatic anxiety, cognitive depression, somatic depression, subjective anxiety, and autonomic anxiety were assessed. Computerized neurocognitive function test (CNT) was performed to assess levels of cognitive functions. We compared the clinical characteristics, levels of cognitive functions, and depressive and anxiety symptoms between schizophrenia patients with TD and without TD. Chi-square test, Fisher's exact test, independent t-test and Mann Whitney U test were conducted to compare two groups. Pearson correlation analysis was conducted to evaluate relationships among the abnormal involuntary movement scale (AIMS), BDI-II, BAI, somatic anxiety, cognitive depression, somatic depression, subjective anxiety, and autonomic anxiety. Results The subjects with TD had significantly lower score on the cognitive depression than those without TD (t = -2.087, p = 0.041). There were significant correlations between the AIMS score and the BDI-II score (r = -0.386, p = 0.035) and between the AIMS score and cognitive depression score (r = - 0.385, p = 0.035). Conclusions Our findings suggest the inverse relationship between severities in TD and depression and support the assumption that there is an inverse relationship between the pathophysiology of TD and depression.

Objectives Although impulsivity has long been thought as an important factor influencing suicidal behaviors, it is unknown whether impulsivity increases the risk of dying from suicidal behaviors and what specific component among constructs of impulsivity contributes to the risk of dying among suicide attempters. Methods To elucidate the association between impulsivity and medical lethality of suicide attempt among suicide attempters, we consecutively recruited 46 suicide attempters who visited an emergency room of a general hospital located in a metropolitan area, Seoul, Republic of Korea, due to suicide attempts and consented to participate in this study. Then we assessed medical lethality with the Beck Lethality Scale (LS) and impulsivity with the Korean version of the Barratt Impulsiveness Scale-11-Revised (BIS). Demographic variables were obtained from medical records and structured social work reports for suicide attempters. Results Although total scores of the BIS did not correlate with LS scores, only the scores of self-control, that is one of the Barrett's six theoretical constructs of impulsivity in which the higher score indicates less self-control and more impulsivity, had a significant positive correlation with scores of LS (p = 0.003). The association remained significant after adjusting for variables known to affect suicide lethality such as job status, recent alcohol consumption, diagnosis of depressive disorders, and having a plan for suicide (${\beta}=0.429$, p = 0.009). Conclusions Not impulsivity in general, but poor self-control, in particular, predicts lethal suicidal behaviors among suicide attempters. The degree of self-control should be evaluated when assessing patients with elevated suicide risk, and proper measures should be installed to prevent possible future lethal suicide attempts.