You will be presented with a collection of medical randomized controlled trial (RCT) reports addressing a shared clinical question -- for instance, the efficacy of a medical intervention on a disease or condition. Given the titles and abstracts of these reports, your task is to generate the conclusion of the systematic review article synthesizing the key findings. Your conclusion should be a few sentences long. In your response, include only the conclusion and no other text. The RCT reports are below.



Title 1:
The effect of smoking cessation on quality of life after lung cancer surgery.
Abstract 1:
OBJECTIVE This study aim ed to evaluate the effect of smoking status on quality of life ( QoL ) after non-small-cell lung cancer surgery with the European Organisation for Research and Treatment of Cancer ( EORTC ) QoL Question naire-C30 and LC13 . METHODS QoL was prospect ively recorded in 70 consecutive patients undergoing lobectomy or pneumonectomy . Question naires were administered preoperatively and 1 , 3 , 6 and 12 months postoperatively ( MPO ) . RESULTS Of all patients analysed , nine ( 13 % ) were non-smokers , 20 ( 29 % ) former smokers , six ( 8 % ) recent quitters and 35 ( 50 % ) current smokers . All four groups had comparable patients ' characteristics and preoperative QoL scores , with exception of non-smokers who had significantly lower physical functioning , role functioning , cognitive functioning and a higher thoracic pain burden . In non-smokers , all QoL scores returned to baseline 3 months after surgery . Former smokers complained of a significant 3-month decrease in physical functioning ( 3 MPO , p = 0.01 ) and a 12-month decrease in role functioning ( 12 MPO , p = 0.01 ) . Former smokers complained of a significant increase in dyspnoea ( 6 MPO , p = 0.001 ) during the first 6 months after surgery . Recent quitters had a longer impairment in physical functioning ( 6 MPO , p = 0.01 ) and a 3-month burden of dyspnoea ( 3 MPO , p=0.02 ) . In current smokers , no return to baseline in physical ( 12 MPO , p = 0.01 ) , role ( 12 MPO , p = 0.01 ) and social functioning ( 12 MPO , p = 0.02 ) and a persistent increase in dyspnoea ( 12 MPO , p = 0.04 ) were reported . Current smokers also complained of increased thoracic pain ( 12 MPO , p = 0.02 ) . Except non-smokers , all patients complained of fatigue the first 3 months after surgery . CONCLUSIONS Smoking cessation is beneficial at any time point to lung cancer surgery and current smoking at the time of surgery is associated with a poor postoperative


Title 2:
Naltrexone effects on short-term and long-term smoking cessation.
Abstract 2:
OBJECTIVES This study examined the efficacy of naltrexone , a long-acting opiate antagonist , as a smoking cessation aid in a double-blind placebo-controlled r and omized trial . It was hypothesized that naltrexone would result in higher quit rates at the end of treatment and six months later . METHODS Subjects were 68 smokers aged 18 to 65 who smoked at least 20 cigarettes daily and wished to stop smoking . They took naltrexone or placebo daily for four weeks and were seen weekly for individual smoking cessation therapy . RESULTS A statistical trend towards a higher overall cessation rate ( cotinine < 15 ng/mL ) at end-of-treatment was observed among subjects treated with naltrexone than placebo ( 46.7 % vs. 26.3 % , respectively , odds ratio = 2.5 , p < .10 ) ; however , this difference was attenuated at six months ( 27 % vs. 15 % , respectively , odds ratio = 1.9 , p = ns ) . Stratified analysis indicated the usefulness of naltrexone primarily for female smokers and those with a history of major depression . These effects remained six months later . CONCLUSION These results provide , at best , mild promise for naltrexone as a smoking cessation drug and provide another instance of a differential response to nicotine dependence treatment according to gender and depression history


Title 3:
Effect of varenicline on individual nicotine withdrawal symptoms: a combined analysis of eight randomized, placebo-controlled trials.
Abstract 3:
INTRODUCTION Concerns exist that varenicline may cause neuropsychiatric side effects . Some of these symptoms ( e.g. , depression , irritability ) have been measured in clinical trials using nicotine withdrawal scales . This study assessed the effect of varenicline on neuropsychiatric and other symptoms , as measured by the Minnesota Nicotine Withdrawal Scale ( MNWS ) . METHODS We analyzed weekly individual MNWS symptom ratings in 8 r and omized double-blind , placebo-controlled smoking cessation trials funded by Pfizer with similar methodology ( n = 2,403 varenicline ; n = 1,434 placebo ) . Ratings for the past 24hr were obtained prior to quitting and starting treatment and at Weeks 1 - 6 and 11 after the quit date . RESULTS In repeated measures analyses controlling for baseline values , ratings for 5 neuropsychiatric symptoms ( depressed mood , irritability , anxiety , difficulty concentrating , and restlessness ) and urge to smoke were lower ( p < .01 ) for varenicline than placebo at each timepoint . Worsening in scores from 0 - 2 ( baseline ) to 4 was less frequent on varenicline than placebo for all ratings except appetite- ( significantly more frequent for varenicline , p < .0001 ) and sleep-related items . Repeated measures analysis for individuals with low levels of exhaled carbon monoxide revealed similar patterns except for a nonsignificant difference for increased appetite . CONCLUSIONS Use of varenicline while trying to quit smoking reduces and does not increase neuropsychiatric symptoms such as depressed mood and irritability measured on the MNWS in smokers without current psychiatric disorders . It is associated with increases in sleep disturbance and appetite although the latter appears due to enabling more subjects to abstain from smoking


Title 4:
Effects of Varenicline on Smoking Cessation in Adults With Stably Treated Current or Past Major Depression
Abstract 4:
UNLABELLED Chinese translation BACKGROUND Depression is overrepresented in smokers . OBJECTIVE To evaluate smoking abstinence and changes in mood and anxiety levels in smokers with depression treated with varenicline versus placebo . DESIGN Phase 4 , multicenter , parallel , 1:1 allocation , double-blind , r and omization trial . R and omization , stratified by antidepressant use and depression score at baseline , was blocked in sizes of 4 . ( Clinical Trials.gov : NCT01078298 ) . SETTING 38 centers in 8 countries . PARTICIPANTS 525 adult smokers with stably treated current or past major depression and no recent cardiovascular events . INTERVENTION Varenicline , 1 mg twice daily , or placebo for 12 weeks , with 40-week nontreatment follow-up . MEASUREMENTS Primary outcome was carbon monoxide-confirmed continuous abstinence rate ( CAR ) for weeks 9 to 12 . Other outcomes included CARs assessed during nontreatment follow-up and ratings of mood , anxiety , and suicidal ideation or behavior . RESULTS 68.4 % versus 66.5 % of the varenicline and placebo groups , respectively , completed the study . Varenicline-treated participants had higher CARs versus placebo at weeks 9 to 12 ( 35.9 % vs. 15.6 % ; odds ratio [ OR ] , 3.35 [ 95 % CI , 2.16 to 5.21 ] ; P < 0.001 ) , 9 to 24 ( 25.0 % vs. 12.3 % ; OR , 2.53 [ CI , 1.56 to 4.10 ] ; P < 0.001 ) , and 9 to 52 ( 20.3 % vs. 10.4 % ; OR , 2.36 [ CI , 1.40 to 3.98 ] ; P = 0.001 ) . There were no clinical ly relevant differences between groups in suicidal ideation or behavior and no overall worsening of depression or anxiety in either group . The most frequent adverse event was nausea  ( varenicline , 27.0 % ; placebo , 10.4 % ) . Two varenicline-group participants died during the nontreatment phase . LIMITATIONS Some data were missing , and power to detect differences between groups was low in rare events . Smokers with untreated depression , with co-occurring psychiatric conditions , or receiving mood stabilizers and antipsychotics were not included . CONCLUSION Varenicline increased smoking cessation  in smokers with stably treated current or past depression without exacerbating depression or anxiety . PRIMARY FUNDING SOURCE Pfizer


Title 5:
Specificity of effects of cognitive behavior therapy on coping, acceptance, and distress tolerance in a randomized controlled trial for smoking cessation.
Abstract 5:
OBJECTIVE Although there is extensive evidence of the efficacy of cognitive-behavioral therapy ( CBT ) , it is less certain what potential mechanisms of change are specifically affected by CBT interventions . This study was intended to test the specific effects of CBT on compensatory coping skills , acceptance , and distress tolerance or persistence . METHOD Using data from a r and omized controlled trial of 8-session group CBT  and a time-matched comparison condition for cigarette smokers , we evaluated CBT effects on compensatory coping skills , self-rated acceptance and behavioral markers of persistence and distress tolerance . Because depression proneness had moderated treatment response in the parent clinical trial ( Kapson & Haaga , 2010 ) , we tested not only main effects ( CBT vs. comparison condition ) but also moderated effects ( treatment condition X depression proneness ) . RESULTS CBT significantly improved compensatory coping skills only among the less depression-prone participants , who were the subset of smokers who did not benefit from CBT in terms of smoking cessation outcomes . There were no specific effects of CBT on acceptance or behavioral persistence . CONCLUSIONS To the extent that CBT had specific effects on compensatory coping skills , it was for the participants who did not benefit clinical ly from the intervention . Much more theory-driven research on multiple c and i date change mechanisms is needed to clarify how effective and specific treatments have their effects , for either patients in general or subsets of patients as in moderated effects
A close and complex relationship between smoking and mental health problems was found .
The study results provided enough evidence to assure that quitting smoking is associated with a reduction of depression , anxiety , and stress , with an improvement of psychological quality of life and positive affect compared with continuing to smoke .
The strength of association was similar for both the general population and study enrolled population s , including those with mental health disorders .
The results of this meta- analysis have direct clinical implication s : the benefits for mental health could motivate physicians and patients to take into account the possibility of smoking cessation