***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Two recent sham-controlled studies found that transcranial direct current stimulation ( tDCS ) was an effective treatment for  depression .  As tDCS is painless , relatively safe and inexpensive , its efficacy in treating depression warrants further investigation . This double-blind , r and omized study tested tDCS at the same stimulation parameters as a previous positive study ( 1 mA current strength , five treatment sessions , active or sham , given on alternate days ) in 40 depressed participants .  Anodal stimulation was centred over the left dorsolateral prefrontal cortex , with the cathode placed on the lateral aspect of the contralateral orbit . tDCS was continued up to a total of ten active sessions per participant . Mood outcomes were measured by psychiatrist raters blind to treatment condition using the Montgomery-Asberg and other depression rating scales . Psychomotor speed was assessed immediately before and after a single tDCS session and attention , frontal executive function , working memory and verbal learning were assessed after each group of five sessions . Overall depression scores improved significantly over ten tDCS treatments , but there was no between-group difference in the five-session , sham-controlled phase . tDCS was found to be safe , with no adverse effects on neuropsychological function , and only minor side-effects . It is recommended that the efficacy of tDCS in depression be further evaluated over a longer treatment period , using enhanced stimulation parameters BACKGROUND Transcranial direct current stimulation ( tDCS ) is a non-invasive brain stimulation modality that has been increasingly used for major depressive disorder ( MDD ) treatment . Although studies in healthy volunteers showed that the technique is well-tolerated , tDCS safety and acceptability have not been sufficiently explored in patients with MDD . METHODS We collected individual patient data from 6 r and omized clinical trials that had been previously identified in a systematic review and meta- analysis . Primary outcomes were safety ( rate of adverse events ) and acceptability ( rate of dropouts ) . Secondary outcomes were clinical , demographic and treatment predictors of the primary outcomes . RESULTS Dropout rates between active ( 8.8 % ) and sham ( 12 % ) groups were not significantly different ( OR= 0.7 , p=0.38 ) . Adverse event rates between active ( 73.5 % ) and sham ( 68.3 % ) groups were not significantly different ( OR= 1.4 , p= 0.23 ) . Higher current densities were associated with lower adverse event rates . LIMITATIONS Dropout reasons were not systematic ally reported and adverse events were not collected using question naires st and ardized across studies . CONCLUSIONS Active tDCS is as acceptable and safe as sham tDCS , as found in r and omized clinical trials of MDD Importance More effective , tolerable interventions for bipolar depression treatment are needed . Transcranial direct current stimulation ( tDCS ) is a novel therapeutic modality with few severe adverse events that showed promising results for unipolar depression . Objective To determine the efficacy and safety of tDCS as an add-on treatment for bipolar depression . Design , Setting , and Participants A r and omized , sham-controlled , double-blind trial ( the Bipolar Depression Electrical Treatment Trial [ BETTER ] ) was conducted from July 1 , 2014 , to March 30 , 2016 , at an outpatient , single-center academic setting . Participants included 59 adults with type I or II bipolar disorder in a major depressive episode and receiving a stable pharmacologic regimen with 17-item Hamilton Depression Rating Scale ( HDRS-17 ) scores higher than 17 . Data were analyzed in the intention-to-treat sample . Interventions Ten daily 30-minute , 2-mA , anodal-left and cathodal-right prefrontal sessions of active or sham tDCS on weekdays and then 1 session every fortnight until week 6 . Main Outcomes and Measures Change in HDRS-17 scores at week 6 . Results Fifty-nine patients ( 40 [ 68 % ] women ) , with a mean ( SD ) age of 45.9 ( 12 ) years participated ; 36 ( 61 % ) with bipolar I and 23 ( 39 % ) with bipolar II disorder were r and omized and 52 finished the trial . In the intention-to-treat analysis , patients in the active tDCS condition showed significantly superior improvement compared with those receiving sham ( & bgr;int = −1.68 ; number needed to treat , 5.8 ; 95 % CI , 3.3 - 25.8 ; P = .01 ) . Cumulative response rates were higher in the active vs sham groups ( 67.6 % vs 30.4 % ; number needed to treat , 2.69 ; 95 % CI , 1.84 - 4.99 ; P = .01 ) , but not remission rates ( 37.4 % vs 19.1 % ; number needed to treat , 5.46 ; 95 % CI , 3.38 - 14.2 ; P = .18 ) . Adverse events , including treatment-emergent affective switches , were similar between groups , except for localized skin redness that was higher in the active group ( 54 % vs 19 % ; P = .01 ) . Conclusions and Relevance In this trial , tDCS was an effective , safe , and tolerable add-on intervention for this small bipolar depression sample . Further trials should examine tDCS efficacy in a larger sample . Trial Registration clinical trials.gov Identifier : BACKGROUND Transcranial direct current stimulation ( tDCS ) is a promising new treatment for depression , however , clinical trials to- date indicate variable efficacy , thereby raising the need to identify inter-individual predictors of response . In the current study we aim ed to investigate pre-treatment neurocognitive performance as a predictor of antidepressant response to tDCS . METHODS Data was pooled from five clinical trials , including two r and omised controlled trials ( RCTs ) , which investigated the antidepressant effects of anodal tDCS administered to the prefrontal cortex . Data from 57 patients were included in the analysis . Mood was assessed before and after an acute course of treatment using the Montgomery-Åsberg Depression Rating Scale . The following neurocognitive tests were administered prior to treatment : Simple and choice reaction time , the Symbol Digit Modalities Test ( SDMT ) , Rey Auditory Verbal Memory Task ( RAVLT ) , Digit Span , and the Controlled Oral Word Association Test ( COWAT ) . RESULTS Better pre-treatment letter fluency performance measured using the COWAT predicted antidepressant response to tDCS after controlling for confounds . LIMITATIONS Small sample size and analysis included data from both RCTs and open label studies . CONCLUSION Pre-treatment letter fluency performance , an ability subserved by the left prefrontal cortex , the primary site of stimulation , is a predictor of response for tDCS treatment for depression . This study highlights the importance of inter-individual neurobiological differences in mediating tDCS antidepressant effects Serotonin affects memory formation via modulating long-term potentiation ( LTP ) and depression ( LTD ) . Accordingly , acute selective serotonin reuptake inhibitor ( SSRI ) administration enhanced LTP-like plasticity induced by transcranial direct current stimulation ( tDCS ) in humans . However , it usually takes some time for SSRI to reduce clinical symptoms such as anxiety , negative mood , and related symptoms of depression and anxiety disorders . This might be related to an at least partially different effect of chronic serotonergic enhancement on plasticity , as compared with single-dose medication . Here we explored the impact of chronic application of the SSRI citalopram ( CIT ) on plasticity induced by tDCS in healthy humans in a partially double-blinded , placebo (PLC)-controlled , r and omized crossover study . Furthermore , we explored the dependency of plasticity induction from the glutamatergic system via N-methyl-D-aspartate receptor antagonism . Twelve healthy subjects received  PLC medication , combined with anodal or cathodal tDCS of the primary motor cortex . Afterwards , the same subjects took CIT ( 20 mg/day ) consecutively for 35 days . During this period , four additional interventions were performed ( CIT and PLC medication with anodal/cathodal tDCS , CIT and dextromethorphan ( 150 mg ) with anodal/cathodal tDCS ) . Plasticity was monitored by motor-evoked potential amplitudes elicited by transcranial magnetic stimulation . Chronic application of CIT increased and prolonged the LTP-like plasticity induced by anodal tDCS for over 24 h , and converted cathodal tDCS-induced LTD-like plasticity into facilitation . These effects were abolished by dextromethorphan . Chronic serotonergic enhancement results in a strengthening of LTP-like glutamatergic plasticity , which might partially explain the therapeutic impact of SSRIs in depression and other neuropsychiatric diseases BACKGROUND Major depressive disorder ( MDD ) is frequently associated with underactivity of the dorsolateral prefrontal cortex ( DLPFC ) which has led to this brain region being identified as an important target for the development of neurobiological treatments . Transcranial direct current stimulation ( tDCS ) administered to the DLPFC has antidepressant efficacy , however the magnitude of antidepressant outcomes are limited . Concurrent cognitive activity has been shown to enhance tDCS induced stimulation effects . Cognitive control training ( CCT ) is a new cognitive therapy for MDD that aims to enhance DLPFC activity via behavioral methods . HYPOTHESIS We tested the hypothesis that co-administration of DLPFC tDCS and CCT would result in a greater reduction in depressive symptomology than administration of tDCS or CCT alone . METHODS 27 adult participants with MDD were r and omized into a three-arm sham-controlled between-groups pilot study comparing the efficacy of 2 mA tDCS + CCT , sham tDCS + CCT and sham CCT + 2 mA tDCS ( 5 sessions administered on consecutive working days ) . Blinded assessment s of depression severity and cognitive control were conducted at baseline , end of treatment and a three week follow up review . RESULTS All three treatment conditions were associated with a reduction in depression severity at the end of five treatment sessions . However , only administration of tDCS + CCT result ed in sustained antidepressant response at follow up , the magnitude of which was greater than that observed immediately following conclusion of the treatment course . CONCLUSIONS The results provide preliminary evidence that concurrent CCT enhances antidepressant outcomes from tDCS . In the current sample , participants receiving concurrent tDCS and CCT continued to improve following cessation of treatment . The clinical superiority of a combined therapeutic approach was apparent even in a small sample and following a relatively short treatment course BACKGROUND We compared transcranial direct‐current stimulation ( tDCS ) with a selective serotonin‐reuptake inhibitor for the treatment of depression . METHODS In a single‐center , double‐blind , noninferiority trial involving adults with unipolar depression , we r and omly assigned patients to receive tDCS plus oral placebo , sham tDCS plus escitalopram , or sham tDCS plus oral placebo . The tDCS was administered in 30‐minute , 2‐mA prefrontal stimulation sessions for 15 consecutive weekdays , followed by 7 weekly treatments . Escitalopram was given at a dose of 10 mg per day for 3 weeks and 20 mg per day thereafter . The primary outcome measure was the change in the 17‐item Hamilton Depression Rating Scale ( HDRS‐17 ) score ( range , 0 to 52 , with higher scores indicating more depression ) . Noninferiority of tDCS versus escitalopram was defined by a lower boundary of the confidence interval for the difference in the decreased score that was at least 50 % of the difference in the scores with placebo versus escitalopram . RESULTS A total of 245 patients underwent r and omization , with 91 being assigned to  escitalopram  , 94 to  tDCS , and 60 to placebo  . In the intention‐to‐treat analysis , the mean ( ±SD ) decrease in the score from baseline was 11.3±6.5 points in the escitalopram group , 9.0±7.1 points in the tDCS group , and 5.8±7.9 points in the placebo group . The lower boundary of the confidence interval for the difference in the decrease for tDCS versus escitalopram ( difference , ‐2.3 points ; 95 % confidence interval [ CI ] , ‐4.3 to ‐0.4 ; P=0.69 ) was lower than the noninferiority margin of ‐2.75 ( 50 % of placebo minus escitalopram ) , so noninferiority could not be cl aim ed . Escitalopram and tDCS were both superior to placebo ( difference vs. placebo , 5.5 points [ 95 % CI , 3.1 to 7.8 ; P<0.001 ] and 3.2 points [ 95 % CI , 0.7 to 5.5 ; P=0.01 ] , respectively ) . Patients receiving tDCS had higher rates of skin redness , tinnitus , and nervousness than did those in the other two groups , and new‐onset mania developed in 2 patients in the tDCS group . Patients receiving escitalopram had more frequent sleepiness and obstipation than did those in the other two groups . CONCLUSIONS In a single‐center trial , tDCS for 
    Output:
    
To conclude , tDCS seems to be safe and devoid of serious adverse effects , although robust efficacy has not been consistently demonstrated in clinical trials assessing an acute treatment course of up to 4 weeks .