Transcranial direct current stimulation (tDCS) is a form of novel brain stimulating method that has attracted interest owing to its relative inexpensiveness and ease of administration. It has been evaluated in many studies for its effectiveness in improving cognitive symptoms in Alzheimer’s disease (AD). However, our understanding regarding its efficacy and the most effective way of administering tDCS (in terms of lead placement to achieve response and prevent harmful consequences) is still evolving. The current meta-analysis was conducted to resolve the above issues. A search using appropriate keywords and medical subject headings was conducted on PubMed, Scopus and DOAJ database. Studies were analysed on pre-defined inclusion and exclusion criteria. Finally 11 studies were included for quantitative analysis from 1,021 obtained from initial search. All the studies included were methodologically of high quality, though an asymmetrical funnel plot raised the possibility of publication bias. tDCS was found to significantly improve the scores on cognition as compared to sham. Anodal tDCS was found to be significantly beneficial in this regards, whereas cathodal and dual stimulation were not. There were no significant difference in the number of drop-outs and adverse reaction in tDCS and sham group. The quality of evidence that we have reviewed in this study is robust. tDCS, particularly anodal tDCS is an effective treatment modality in AD. It is well tolerated in patients with AD. However, further studies are warranted to probe the role of tDCS in other domains of AD.

OBJECTIVE: Unipolar and bipolar depression (UD and BD) differ strikingly in respect to neurobiology, course and management, but their apparent clinical similarity often leads to misdiagnosis resulting in chronicity of course and treatment failure. In this study we have tried to assess whether UD and BD can be differentiated on the basis of their dissociative symptoms. METHODS: Thrty-six UD patients and 35 BD patients in active episodes, without any psychiatric comorbidity were selected from outpatient department and compared for depressive and dissociative symptoms using Hamilton Depression Rating Scale and Dissociative Experience Scale-II (DES-II). RESULTS: We found that thought the two groups didn’t differ in terms of the socio-demographic or clinical variables, BD group had significantly higher dissociative experience (U=343, p=0.001) than UD and the difference remained significant even after adjusting for the confounding factors. CONCLUSION: Our study shows that dissociative symptoms are significantly more prevalent in the depressive episodes of bipolar affective disorder as compared to the UD and can be an important tool in differentiating between the two disorders with very similar clinical profile. The difference can be measured using a simple self-report questionnaire like DES-II.
Bipolar Disorder* ; Comorbidity ; Depression ; Diagnostic Errors ; Dissociative Disorders ; Humans ; Mood Disorders ; Neurobiology ; Outpatients ; Treatment Failure