***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: BACKGROUND Effective internet-based programs for depression usually incorporate a component that provides telephone or email contact . Open access websites , without such contact , show high rates of attrition and poorer outcomes . The present study was design ed as an exploratory investigation of the parameters that influence the effectiveness and retention of users on open access websites . We investigated whether brief cognitive behaviour therapy ( CBT ) was as effective as an extended version , whether add-on components of behaviour therapy or stress management contributed to positive outcomes , and whether longer programs were associated with greater attrition . METHOD An online r and omized controlled trial ( RCT ) was conducted between 13 January 2005 and 26 May 2005 ( 19 weeks ) . A total of 2794 registrants ( 1846 women and 948 men ; median age category 35 - 44 years ) with elevated scores on the Goldberg Depression Scale of 5.96 ( S.D.=2.09 ) elected online to be r and omized to one of six versions of a CBT website . The versions were compiled consisting of various components of brief CBT , extended CBT , behaviour strategies , stress management and problem solving . RESULTS A total of 20.4 % of participants completed the assigned intervention . The interaction of measurement occasion and treatment version was significant [ F(13,131)=2.20 , p=0.01 ] . A single module of brief introductory CBT was not effective in reducing depression symptoms . However , extended CBT with or without the addition of behaviour strategies result ed in the reduction of depression . CONCLUSIONS Brief CBT-based interventions are not as effective as extended interventions . However , longer programs are associated with higher rates of dropout ABSTRACT Objective : To investigate whether gum chewing affects perceived levels of everyday stress among persons who ( 1 ) regularly chew gum or ( 2 ) do not chew gum on a regular basis . Research design and methods : Two Internet-based studies were conducted . Study 1 enrolled participants who chewed gum ≥4 days per week , chewed ≥11 pieces of gum per week , and chewed gum during the previous week ( frequent or heavy chewers , n = 280 ) . Study 2 enrolled participants who had chewed gum previously but did so infrequently and had not chewed during at least the 7 days before recruitment ( n = 212 ) . Both studies used a r and omized , crossover design : each participant either chewed gum or abstained from chewing for a number of sequential days , then switched to the opposite behavior for the same number of days . Stress levels were assessed by means of self-reported responses to the State-Trait Anxiety Inventory ( STAI ) at screening and after each test sequence . Results : More participants ( 54 % in study 1 [ p ≤ 0.10 ] and 57 % in study 2 [ p ≤ 0.05 ] ) reported that chewing gum reduced their stress level at least a little , compared with those who reported no effect on or an increase in stress . In both studies , mean STAI state scores increased significantly after the abstaining period , indicating an increase in the perceived level of stress , and decreased significantly after the gum-chewing period . Particular stress-specific emotions ( e.g. , not feeling relaxed , feeling tense ) were reported to have significantly increased when participants abstained from chewing gum and to have decreased when they chewed . More severe levels of stress ( e.g. , being upset or frightened ) were not affected by chewing or abstaining from chewing gum . The studies had several potential limitations , including self-reporting , a large initial recruitment , and the need for habit alteration . Conclusions : The findings point to a relationship between decreased stress and gum chewing and suggest chewing gum may help reduce perceived levels of everyday stress Background Although many smokers seek Internet-based cessation assistance , few studies have experimentally evaluated long-term cessation rates among cigarette smokers who receive Internet assistance in quitting . Objective The purpose of this study is to describe long-term smoking cessation rates associated with 6 different  Internet-based cessation services  and the variation among them , to test the hypothesis that interactive and tailored Internet services yield higher long-term quit rates than more static Web-posted assistance , and to explore the possible effects of level of site utilization and a self-reported indicator of depression on long-term cessation rates . Method In 2004 - 05 , a link was placed on the American Cancer Society ( ACS ) website for smokers who wanted help in quitting via the Internet . The link led smokers to the QuitLink study website , where they could answer eligibility questions , provide informed consent , and complete the baseline survey . Enrolled participants were r and omly assigned to receive emailed access to one of five tailored interactive sites provided by cooperating research partners or to a targeted , minimally interactive ACS site with text , photographs , and graphics providing stage-based quitting advice and peer modeling . Results 6451 of the visitors met eligibility requirements and completed consent procedures and the baseline survey . All of these smokers were r and omly assigned to one of the six experimental groups . Follow-up surveys done online and via telephone interviews at approximately 13 months after r and omization yielded 2468 respondents ( 38 % ) and found no significant overall quit rate differences among those assigned to the different websites ( P = .15 ) . At baseline , 1961 participants ( 30 % ) reported an indicator of depression . Post hoc analyses found that this group had significantly lower 13-month quit rates than those who did not report the indicator ( all enrolled , 8 % vs 12 % , P < .001 ; followed only , 25 % vs 31 % , P = .003 ) . When the 4490 participants ( 70 % ) who did not report an indicator of depression at baseline were separated for analysis , the more interactive , tailored sites , as a whole , were associated with higher quitting rates than the less interactive ACS site : 13 % vs 10 % ( P = .04 ) among 4490 enrolled and 32 % vs 26 % ( P = .06 ) among 1798 followed . Conclusions These findings show that Internet assistance is attractive and potentially cost-effective and suggest that tailored , interactive websites may help cigarette smokers who do not report an indicator of depression at baseline to quit and maintain cessation Background  Online computer-tailored smoking cessation programs  have not yet been compared directly . Objective To compare the efficacy of two Internet-based , computer-tailored smoking cessation programs . Methods R and omized controlled trial conducted in 2003 - 2004 . Visitors to a smoking cessation website were r and omly assigned to either an original online , interactive smoking cessation program or to a modified program . Both programs consisted of tailored , personalized counseling letters based on participants ' characteristics , followed by monthly email reminders . The original program was based on psychological and addiction theory , and on preliminary research conducted in the same population . The modified program was shorter and contained more information on nicotine replacement therapy and nicotine dependence , and less information on health risks and coping strategies . In both programs , 1 month and 2 months after entering the study , participants were invited by email to answer the same tailoring question naire again in order to receive a second counseling letter . Participants in both programs obtained , on average , 1.2 feedback counseling letters over 2.5 months , and 84 % received only 1 feedback letter . The outcome was self-reported smoking abstinence ( no puff of tobacco in the previous 7 days ) , assessed 2.5 months after entry in the program . We report results from intention-to-treat ( ITT ) analyses , where all non-respondents at follow-up were counted as smokers . Results The baseline question naire was answered by a total of 11969 current ( 74 % ) and former ( 26 % ) smokers , and the follow-up survey by 4237 people ( 35 % ) . In an ITT analysis , abstinence rates in baseline current smokers were respectively 10.9 % and 8.9 % ( odds ratio [OR]=1.24 , 95 % confidence interval [CI]1.08 - 1.43 , P=.003 ) in the original and modified programs , and 25.2 % and 15.7 % ( OR=1.81 , CI 1.51 - 2.16 , P<.001 ) in baseline former smokers . While we found statistically significant differences in quit rates in smokers in the contemplation stage favoring the original program ( OR=1.54 , CI 1.18 - 2.02 , P=.002 ) , no between-group differences in quit rates were observed in smokers in the precontemplation ( OR=1.07 , CI 0.36 - 3.14 , P=.91 ) and preparation ( OR=1.15 , CI 0.97 - 1.37 , P=.10 ) stages of change . Conclusions In smokers in the contemplation stage of change and in former smokers , the original program produced higher smoking abstinence rates than the modified program Background Online self-help interventions for problem drinkers show promising results , but the effectiveness of online therapy with active involvement of a therapist via the Internet only has not been examined . Objective The objective of our study was to evaluate an e-therapy program with active therapeutic involvement for problem drinkers , with the hypotheses that e-therapy would ( 1 ) reduce weekly alcohol consumption , and ( 2 ) improve health status . Reasons for dropout were also systematic ally investigated . Method In an open r and omized controlled trial , Dutch-speaking problem drinkers in the general population were r and omly assigned ( in blocks of 8 , according to a computer-generated r and om list ) to the 3-month e-therapy program ( n = 78 ) or the waiting list control group ( n = 78 ) . The e-therapy program consisted of a structured 2-part online treatment program in which the participant and the therapist communicated asynchronously , via the Internet only . Participants in the waiting list control group received “ no-reply ” email messages once every 2 weeks . The primary outcome measures were ( 1 ) the difference in the score on weekly alcohol consumption , and ( 2 ) the proportion of participants drinking under the problem drinking limit . Intention-to-treat analyses were performed using multiple imputations to deal with loss to follow-up . A dropout question naire was sent to anyone who did not complete the 3-month assessment . Reasons for dropout were independently assessed by the first and third author . Results Of the 156 individuals who were r and omly assigned , 102 ( 65 % ) completed assessment at 3 months . In the intention-to-treat analyses , the e-therapy group ( n = 78 ) showed a significantly greater decrease in alcohol consumption than those in the control group ( n = 78 ) at 3 months . The e-therapy group decreased their mean weekly alcohol consumption by 28.8 units compared with 3.1 units in the control group , a difference in means of 25.6 units on a weekly basis ( 95 % confidence interval 15.69 - 35.80 , P < .001 ) . The between-group effect size ( pooled SD ) was large ( d = 1.21 ) . The results also showed that 68 % ( 53/78 ) of the e-therapy group was drinking less than 15 ( females ) or 22 ( males ) units a week , compared with 15 % ( 12/78 ) in the control group ( OR 12.0 , number needed to treat 1.9 , P < .001 ) . Dropout analysis showed that the main reasons for dropouts ( n = 54 ) were personal reasons unrelated to the e-therapy program , discomfort with the treatment protocol , and satisfaction with the positive results achieved . Conclusions E-therapy for problem drinking is an effective intervention that can be delivered to a large population who otherwise do not seek help for their drinking problem . Insight into reasons for dropout can help improve e-therapy programs to decrease the number of dropouts . Additional research is needed to directly compare the effectiveness of the e-therapy program with a face-to-face treatment program . Trial registration IS RCT N39104853 ; http://controlled-trials.com/IS RCT N39104853/IS RCT N39104853 ( Archived by WebCite at http://www.webcitation.org/5uX1R5xfW Background Interventions delivered via the Internet have the potential to address the problem of hazardous alcohol consumption at minimal incremental cost , with potentially major public health implication s. It was hypothesised that providing access to a psychologically enhanced website would result in greater reductions in drinking and related problems than giving access to a typical alcohol website simply providing information on potential harms of alcohol . DYD- RCT Trial registration : IS RCT N 31070347 . Methodology /Principal Findings A two-arm r and omised controlled trial was conducted entirely on-line through the Down Your Drink ( DYD ) website . A total of 7935 individuals who screened positive for hazardous alcohol consumption were recruited and r and omized . At entry to the trial , the geometric mean reported past week alcohol consumption was 46.0 ( SD 31.2 ) units . Consumption levels reduced substantially in both groups at the principal 3 month assessment point to an average of 26.0 ( SD 22.3 ) units . Similar changes were reported at 1 month and 12 months . There were no significant differences between the groups for either alcohol consumption at 3 months ( intervention : control ratio of geometric means 1.03 , 95 % CI 0.97 to 1.10 ) or for this outcome and the main secondary outcomes at any of the assessment s. The results were not material ly changed following imputation of missing values , nor was there any evidence that the impact of the intervention varied with baseline measures or level of exposure to the intervention . Conclusions 
    Output:
    
It is theoretically possible but perhaps difficult to test the effectiveness of health interventions rigorously with RCTs conducted fully or primarily over the internet .
The use of the internet to conduct trials is more suited to pragmatic rather than explanatory trials .