***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: Seasonal affective disorder ( SAD ) is a syndrome characterized by recurrent depressions that occur annually at the same time each year . We describe 29 patients with SAD ; most of them had a bipolar affective disorder , especially bipolar II , and their depressions were generally characterized by hypersomnia , overeating , and carbohydrate craving and seemed to respond to changes in climate and latitude . Sleep recordings in nine depressed patients confirmed the presence of hypersomnia and showed increased sleep latency and reduced slow-wave ( delta ) sleep . Preliminary studies in 11 patients suggest that extending the photoperiod with bright artificial light has an antidepressant effect BACKGROUND To our knowledge , this is the first prospect i ve natural history study of weekly symptomatic status of patients with bipolar I disorder ( BP-I ) during long-term follow-up . METHODS Analyses are based on ongoing prospect i ve follow-up of 146 patients with Research Diagnostic Criteria BP-I , who entered the National Institute of Mental Health ( Bethesda , Md ) Collaborative Depression Study from 1978 through 1981 .  Weekly affective symptom status ratings were analyzed by polarity and severity , ranging from asymptomatic , to subthreshold levels , to full-blown major depression and mania . Percentages of follow-up weeks at each level as well as number of shifts in symptom status and polarity during the entire follow-up period were examined . Finally , 2 new measures of chronicity were evaluated in relation to previously identified predictors of chronicity for BP-I. RESULTS Patients with BP-I were symptomatically ill 47.3 % of weeks throughout a mean of 12.8 years of follow-up . Depressive symptoms ( 31.9 % of total follow-up weeks ) predominated over manic/hypomanic symptoms ( 8.9 % of weeks ) or cycling/mixed symptoms ( 5.9 % of weeks ) . Subsyndromal , minor depressive , and hypomanic symptoms combined were nearly 3 times more frequent than syndromal-level major depressive and manic symptoms ( 29.9 % vs 11.2 % of weeks , respectively ) . Patients with BP-I changed symptom status an average of 6 times per year and polarity more than 3 times per year . Longer intake episodes and those with depression-only or cycling polarity predicted greater chronicity during long-term follow-up , as did comorbid drug-use disorder . CONCLUSIONS The longitudinal weekly symptomatic course of BP-I is chronic . Overall , the symptomatic structure is primarily depressive rather than manic , and subsyndromal and minor affective symptoms predominate . Symptom severity levels fluctuate , often within the same patient over time . Bipolar I disorder is expressed as a dimensional illness featuring the full range ( spectrum ) of affective symptom severity and polarity BACKGROUND The aim of the study was to examine the efficacy and safety of morning bright light therapy ( BLT ) in the treatment of patients with a current major depressive episode ( MDE ) in bipolar and unipolar disorder without a seasonal pattern . It was a r and omized , sham-controlled trial . METHODS Adults , ages 18 - 70 years were r and omized to treatment either with BLT or a sham negative ion generator ( as a placebo control ) . The subjects were required to be on a stable and therapeutic dose of psychotropic medication for at least 4 weeks prior to enrollment and their treatment had to be insufficiently effective . Their clinical state was monitored at the baseline and at the end of treatment . The Hamilton Depression Rating Scale-21 items ( HDRS-21 ) , Montgomery-Asberg Depression Rating Scale ( MADRS ) , Beck Depression Inventory ( BDI-II ) , Clinical Global Impression-Severity ( CGI-S ) and Patient Global Impression ( PGI ) were used . The results were analyzed with an intention-to-treat ( ITT ) analysis . RESULTS Ninety-five patients were enrolled ( 50 diagnosed with bipolar disorder and 45 with unipolar depression ) . Fifty-two patients were r and omized to treatment with BLT and forty-three were in the placebo group ( ITT population ) . Eighty-three subjects completed the study . There were 12 dropouts ( 5 in the light group and 7 in the placebo group ) . After 14 days of treatment , a significant improvement was found in all groups ( p<0.001 ) . The subjects treated with BLT did not significantly differ in terms of improvement in HDRS-21 scores at the endpoint when compared to patients treated with placebo ( p=0.2 ) . However , further analysis demonstrated significantly higher response ( 50 % v. 27.9 % , p=0.02 ) and remission rates ( 28.8 % v. 11.6 % , p=0.04 ) among patients treated with morning BLT when compared to placebo group . It should be noted that in the population of drug-resistant patients , BLT was more efficacious than placebo . There were no statistically significant differences between unipolar and bipolar disorders ( p=0.4 ) . CONCLUSION Although overall improvement in HDRS-21 scores were not superior in the BLT group , both response and remission rates were significantly higher among patients treated with BLT relative to those receiving the sham intervention . BLT was also more efficacious than placebo in the population of patients with drug-resistant depression . Further studies to define the sub population of patients with non-seasonal depression who may benefit the most from BLT are needed BACKGROUND We tested the hypothesis that the early improvement in mood after the first hour of bright light treatment compared to control dim-red light would predict the outcome at six weeks of bright light treatment for depressed mood in patients with Seasonal Affective Disorder ( SAD ) . We also analyzed the value of Body Mass Index ( BMI ) and atypical symptoms of depression at baseline in predicting treatment outcome . METHODS Seventy-eight adult participants were enrolled . The first treatment was controlled crossover , with r and omized order , and included one hour of active bright light treatment and one hour of control dim-red light , with one-hour washout .  Depression was measured on the Structured Interview Guide for the Hamilton Rating Scale for Depression-SAD version ( SIGH-SAD ) . The predictive association of depression scores changes after the first session . BMI and atypical score balance with treatment outcomes at endpoint were assessed using multivariable linear and logistic regressions . RESULTS No significant prediction by changes in depression scores after the first session was found . However , higher atypical balance scores and BMI positively predicted treatment outcome . LIMITATIONS Absence of a control intervention for the six-weeks of treatment ( only the first session in the laboratory was controlled ) . Exclusion of patients with comorbid substance abuse , suicidality and bipolar I disorder , and patients on antidepressant medications , reducing the generalizability of the study . CONCLUSION Prediction of outcome by early response to light treatment was not replicated , and the previously reported prediction of baseline atypical balance was confirmed . BMI , a parameter routinely calculated in primary care , was identified as a novel predictor , and calls for replication and then exploration of possible mediating mechanisms BACKGROUND Bright light therapy ( BLT ) is an effective treatment for seasonal affective disorder and non- seasonal depression . The efficacy of BLT in treating patients with bipolar disorder is still unknown . AIMS The aim of this study is to examine the efficacy , onset time and clinical safety of BLT in treating patients with acute bipolar depression as an adjunctive therapy ( trial registration at Clinical Trials.gov : NCT02009371 ) . METHODS This was a multi-center , single blind , r and omized clinical trial . Seventy-four participants were r and omized in one of two treatment conditions : BLT and control ( dim red light therapy , dRLT ) .  Sixty-three participants completed the study ( 33 BLT , 30 dRLT ) . Light therapy lasted for two weeks , one hour every morning . All participants were required to complete several scales assessment s at baseline , and at the end of weeks 1 and 2 . The primary outcome measures were the clinical efficacy of BLT  which was assessed by the reduction rate of HAMD-17 scores , and the onset time of BLT  which was assessed by the reduction rate of QIDS-SR16 scores . The secondary outcome measures were rates of switch into hypomania or mania and adverse events . RESULTS 1 ) Clinical efficacy :  BLT showed a greater ameliorative effect on bipolar depression than the control , with response rates of 78.19 % vs. 43.33 % respectively ( p < 0.01 ) . 2 ) Onset day : Median onset day was 4.33 days in BLT group . 3 )  BLT-emergent hypomania : No participants experienced symptoms of hypomania . 4 ) Side effects : No serious adverse events were reported . CONCLUSION BLT can be considered as an effective and safe adjunctive treatment for patients with acute bipolar depression For 30 years , bright light therapy ( BLT ) has been considered as an effective , well-tolerated treatment for seasonal affective disorder ( SAD ) . Because of low response rates , new treatment strategies are needed for bipolar depression ( BD ) , which resembles SAD in certain respects . Few placebo-controlled studies of BLT efficacy have been carried out for BD . Accordingly , this study evaluates the efficacy and safety of BLT as an add-on treatment for BD . Thirty-two BD out patients were r and omly assigned to BLT ( 10000lx ) or dim light ( DL , < 500lx ) . During a two-week period , light was administered each morning for 30min . The Hamilton Rating Scale for Depression and the Montgomery-Ǻsberg Depression Rating Scale assessed clinical outcome , and the UKU Side Effects Rating Scale evaluated side effects . No significant difference was observed in baseline depression scores in the  two groups . Response rates for BLT and DL were 81 % and 19 % , and remission rates were 44 % and 12.5 % , respectively . Analyses showed statistically significant reductions in depression scores for the BLT group compared with the DL group on all scales . Side effects were similar in both groups , with headache as the most common side effect . The results suggest that BLT is an effective and safe add-on treatment for BD Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more BACKGROUND This is the first prospect i ve longitudinal study , to our knowledge , of the natural history of the weekly symptomatic status of bipolar II disorder ( BP-II ) . METHODS Weekly affective symptom status ratings for 86 patients with BP-II were based on interviews conducted at 6- or 12-month intervals during a mean of 13.4 years of prospect i ve follow-up . Percentage of weeks at each symptom severity level and the number of shifts in symptom status and polarity were examined . Predictors of chronicity for BP-II were evaluated using new chronicity measures . Chronicity was also analyzed in relation to the percentage of follow-up weeks with different types of somatic treatment . RESULTS Patients with BP-II were symptomatic 53.9 % of all follow-up weeks : depressive symptoms ( 50.3 % of weeks ) dominated the course over hypomanic ( 1.3 % of weeks ) and cycling/mixed ( 2.3 % of weeks ) symptoms . Subsyndromal , minor depressive , and hypomanic symptoms combined were 3 times more common than major depressive symptoms . Longer intake episodes , a family history of affective disorders , and poor previous social functioning predicted greater chronicity . Prescribed somatic treatment did not correlate significantly with symptom chronicity .  Patients with BP-II of brief ( 2 - 6 days ) vs longer ( > or = 7 days ) hypomanias were not significantly different on any measure . CONCLUSIONS The longitudinal symptomatic course of BP-II is chronic and is dominated by depressive rather than hypomanic or cycling/mixed symptoms . Symptom severity fluctuates frequently within the same patient over time , involving primarily symptoms of minor and subsyndromal severity . Longitudinally , BP-II is expressed as a dimensional illness involving the full severity range of depressive and hypomanic symptoms . Hypomania of long or short duration in BP-II seems to be part of the same disease process Treatment of bipolar disorder often results in patients taking several drugs in an attempt to alleviate residual depressive symptoms , which can lead to an accumulation of side effects . New treatments for bipolar depression that do not increase the side effect burden are needed . One nonpharmacological treatment with few side effects , bright light therapy , has been shown to be an effective therapy for seasonal affective disorder , yet has not been extensively studied for other forms of depression . Forty-four adults with bipolar disorder , depressed phase were r and omized to treatment with bright light therapy , low-density or high-density negative ion generator for 8 weeks . The primary measure of efficacy was the Structured Interview Guide for the Hamilton Depression Rating Scale with Atypical Depression Supplement ( SIGH-ADS ) . Adverse events were assessed using the Young Mania Rating Scale ( YMRS ) and Systematic Assessment for Treatment Emergent effects ( SAFTEE ) . All outcome variables were statistically analyzed using a mixed model repeated measure analysis of variance ( ANOVA ) . The results showed no statistically significant differences between groups in any outcome measures at study end point ; adverse events , including switches into hypomania , were rare . Further research is needed to determine the efficacy of bright light therapy in this population BACKGRO 
    Output:
    
Conclusion There is positive but nonconclusive evidence that adjunctive light therapy reduces symptoms of bipolar depression and increases clinical response .
Light therapy is well tolerated with no increased risk of affective switch