Does smoking cessation result in improved mental health? A comparison of regression modelling and propensity score matching

Nicotine dependence and incident psychiatric disorders: prospective evidence from US national study

We examined the prospective associations between nicotine dependence and the likelihood of psychiatric and substance use disorders in the general adult population. Participants came from a nationally representative sample of US adults aged 18 years or older, who were interviewed 3 years apart in the National Epidemiologic Survey on Alcohol and Related Conditions (Wave 1, 2001-2002; Wave 2, 2004-2005). The primary analyses were limited to 32,671 respondents (13,751 male (47.9% weighted); mean age of 45 years (SD = 0.18)) who were interviewed in both waves. We used multiple regression and propensity score matching (PSM) to estimate the strength of independent associations between nicotine dependence related to the use of tobacco products at Wave 1 and incident psychiatric disorders at Wave 2. Psychiatric disorders were measured with a structured interview (Alcohol Use Disorder and Associated Disabilities Interview Schedule-DSM-IV). All analyses adjusted for multiple potential confounders, including childhood (family history of substance use disorders, parental loss, vulnerable family environment), early-adolescence (self-esteem, social deviance, conduct disorder), late-adolescence (education, personality and psychiatric disorders), adulthood (divorce, stressful life events, social deviance, quality of life, history of alcohol or other substance use disorder), and sociodemographic factors. Multiple regression analysis and PSM converged in indicating that nicotine dependence was associated with significantly increased incidence of any psychiatric disorder (OR = 1.39(95%CI:1.20;1.60)), including substance use disorders (OR = 1.91(95%CI:1.47;2.47)), and anxiety disorders (OR = 1.31(95%CI:1.06;1.62)). Population Attributable Risk Proportions were substantial, ranging from 12.5%(95%CI:8.10;17.0) for any psychiatric disorder to 33.3%(95%CI:18.7;48.0) for any other drug use disorder. Supplementary analyses also indicated significant associations between nicotine dependence and persistence of psychiatric and substance use disorders among patients having a disorder at Wave 1. In the general adult population, nicotine dependence is associated with an increased likelihood for several psychiatric and substance use disorders. Given its high prevalence, these findings have important public health implications.

Association between tobacco smoke exposure and depression: the NHANES 2005-2018 and Mendelian randomization study

OBJECTIVE

The relationship between tobacco smoke exposure (TSE) and depression is controversial. This study combined observational research and Mendelian randomization (MR) to explore the relationship of depression with both smoking status and cotinine levels.

METHOD

We collected relevant data from the National Health and Nutrition Examination Survey (NHANES) database from 2005 to 2018, and used weighted multifactorial logistic regression modelling to assess the correlation between TSE and depression, and assessed the causal relationship of depression with both smoking status and cotinine levels by MR.

RESULT

Current smokers had the highest risk of depression (OR 1.94; P < 0.01); there was a positive trend for correlation between daily smoking and depression (OR 1.66; P for trend < 0.01). Serum ketamine levels above 3.00 ng/ml had a higher risk of depression (OR 2.13; P < 0.001). MR results showed that current smoking (OR = 4.66; P < 0.001) and previous smoking (OR 2.09; P < 0.01) were risk factors for the onset of depression, and that there was no causal association between cotinine levels and depression.

CONCLUSION

Smoking is significantly associated with depression and plays a potential causal role in the development of depression. Cotinine was significantly associated with depression, however MR results showed no causal relationship between cotinine and depression.

A cross-sectional study of smoking and depression among US adults: NHANES (2005-2018)

Background

The relationship between smoking and depression remains controversial. This study aimed to investigate the association between smoking and depression from three aspects: smoking status, smoking volume, and smoking cessation.

Methods

Data from adults aged ≥20 who participated in the National Health and Nutrition Examination Survey (NHANES) between 2005 and 2018 were collected. The study gathered information about the participants' smoking status (never smokers, previous smokers, occasional smokers, daily smokers), smoking quantity per day, and smoking cessation. Depressive symptoms were assessed using the Patient Health Questionnaire (PHQ-9), with a score ≥10 indicating the presence of clinically relevant symptoms. Multivariable logistic regression was conducted to evaluate the association of smoking status, daily smoking volume, and smoking cessation duration with depression.

Results

Previous smokers [odds ratio (OR) = 1.25, 95% confidence interval (CI): 1.05-1.48] and occasional smokers (OR = 1.84, 95% CI: 1.39-2.45) were associated with a higher risk of depression compared with never smokers. Daily smokers had the highest risk of depression (OR = 2.37, 95% CI: 2.05-2.75). In addition, a tendency toward a positive correlation was observed between daily smoking volume and depression (OR = 1.65, 95% CI: 1.24-2.19) (P for trend < 0.05). Furthermore, the longer the smoking cessation duration, the lower the risk of depression (OR = 0.55, 95% CI: 0.39-0.79) (P for trend < 0.05).

Conclusions

Smoking is a behavior that increases the risk of depression. The higher the smoking frequency and smoking volume, the higher the risk of depression, whereas smoking cessation is associated with decreased risk of depression, and the longer the smoking cessation duration, the lower the risk of depression.

Association of alpha-fetoprotein and metastasis for small hepatocellular carcinoma: A propensity-matched analysis

Metastasis is crucial for the prognosis of hepatocellular carcinoma (HCC). Distinguishing the potential risk factors for distant metastasis in small HCC (diameter ≤ 5 cm) is of great significance for improving the prognosis. HCC patients in the Surveillance, Epidemiology and End Results (SEER) registry with tumors ≤ 5 cm in diameter between January 2010 and December 2015 were retrieved. Demographic and clinicopathological metrics were extracted, including age, sex, race, marital status, tumor size, histological grade, T stage, N stage, M stage, alpha-fetoprotein (AFP), and liver fibrosis score. Univariate and multivariate logistic regression analyses were used to identify independent risk factors correlated with extrahepatic metastasis in small HCC. Propensity score matching (PSM) analysis was performed to balance the confounding factors in baseline characteristics. A total of 4176 eligible patients were divided into a non-metastasis group (n = 4033) and a metastasis group (n = 143) based on metastasis status. In multivariate analysis, larger tumor size, poor histological differentiation, regional lymph node metastasis, and elevated serum AFP levels were identified as independent risk factors for distant metastasis (P < 0.05), while age, sex, race, marital status, and liver fibrosis score were not associated with extrahepatic metastasis. After propensity score analysis, the AFP level was no longer associated with metastatic risk. The present study provided no evidence for a correlation between the clinical threshold of AFP and metastasis in small hepatocellular carcinoma.

The Acceptability and Effectiveness of Videos Promoting Smoking Cessation Among Australians Experiencing Mental Illness

There are high rates of tobacco smoking among people who experience mental illness (MI). While videos are an effective method of disseminating health-related information, there is limited research investigating the effectiveness of video-delivered education promoting smoking cessation among people living with MI. This formative study aimed to investigate the effectiveness and acceptability of targeted video resources providing smoking cessation information and advice to smokers with MI. This study used a mixed-method design; 29 Australian smokers living with MI completed a preinterview survey including 12 questions assessing knowledge about smoking cessation, watched six videos developed by the research team providing information about smoking cessation, took part in semistructured interviews about the videos' quality, content, and format, and then completed a postinterview survey identical to the preinterview survey to assess changes in smoking cessation-related knowledge. A Wilcoxon signed rank test was used to calculate changes in cessation-related knowledge, and thematic analysis was used to identify common themes in qualitative data. We found a statistically significant increase in participants' smoking cessation-related knowledge scores after watching the videos. Participants indicated an overall high level of acceptability of the videos' quality, content, and format, and findings from the semistructured interviews reflected these favorable views. This study's findings provide a new understanding of the effectiveness and acceptability of customized video-based education to promote smoking cessation among people living with MI, and can be used to inform the content and focus of video resources aimed at increasing knowledge about smoking cessation for people experiencing MI.

Smoking cessation for improving mental health

BACKGROUND

There is a common perception that smoking generally helps people to manage stress, and may be a form of 'self-medication' in people with mental health conditions. However, there are biologically plausible reasons why smoking may worsen mental health through neuroadaptations arising from chronic smoking, leading to frequent nicotine withdrawal symptoms (e.g. anxiety, depression, irritability), in which case smoking cessation may help to improve rather than worsen mental health.

OBJECTIVES

To examine the association between tobacco smoking cessation and change in mental health.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialised Register, Cochrane Central Register of Controlled Trials, MEDLINE, Embase, PsycINFO, and the trial registries clinicaltrials.gov and the International Clinical Trials Registry Platform, from 14 April 2012 to 07 January 2020. These were updated searches of a previously-conducted non-Cochrane review where searches were conducted from database inception to 13 April 2012.  SELECTION CRITERIA: We included controlled before-after studies, including randomised controlled trials (RCTs) analysed by smoking status at follow-up, and longitudinal cohort studies. In order to be eligible for inclusion studies had to recruit adults who smoked tobacco, and assess whether they quit or continued smoking during the study. They also had to measure a mental health outcome at baseline and at least six weeks later.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Our primary outcomes were change in depression symptoms, anxiety symptoms or mixed anxiety and depression symptoms between baseline and follow-up. Secondary outcomes  included change in symptoms of stress, psychological quality of life, positive affect, and social impact or social quality of life, as well as new incidence of depression, anxiety, or mixed anxiety and depression disorders. We assessed the risk of bias for the primary outcomes using a modified ROBINS-I tool.  For change in mental health outcomes, we calculated the pooled standardised mean difference (SMD) and 95% confidence interval (95% CI) for the difference in change in mental health from baseline to follow-up between those who had quit smoking and those who had continued to smoke. For the incidence of psychological disorders, we calculated odds ratios (ORs) and 95% CIs. For all meta-analyses we used a generic inverse variance random-effects model and quantified statistical heterogeneity using I2. We conducted subgroup analyses to investigate any differences in associations between sub-populations, i.e. unselected people with mental illness, people with physical chronic diseases. We assessed the certainty of evidence for our primary outcomes (depression, anxiety, and mixed depression and anxiety) and our secondary social impact outcome using the eight GRADE considerations relevant to non-randomised studies (risk of bias, inconsistency, imprecision, indirectness, publication bias, magnitude of the effect, the influence of all plausible residual confounding, the presence of a dose-response gradient).

MAIN RESULTS

We included 102 studies representing over 169,500 participants. Sixty-two of these were identified in the updated search for this review and 40 were included in the original version of the review.  Sixty-three studies provided data on change in mental health, 10 were included in meta-analyses of incidence of mental health disorders, and 31 were synthesised narratively.  For all primary outcomes, smoking cessation was associated with an improvement in mental health symptoms compared with continuing to smoke: anxiety symptoms (SMD -0.28, 95% CI -0.43 to -0.13; 15 studies, 3141 participants; I2 = 69%; low-certainty evidence); depression symptoms: (SMD -0.30, 95% CI -0.39 to -0.21; 34 studies, 7156 participants; I2 = 69%' very low-certainty evidence);  mixed anxiety and depression symptoms (SMD -0.31, 95% CI -0.40 to -0.22; 8 studies, 2829 participants; I2 = 0%; moderate certainty evidence).  These findings were robust to preplanned sensitivity analyses, and subgroup analysis generally did not produce evidence of differences in the effect size among subpopulations or based on methodological characteristics. All studies were deemed to be at serious risk of bias due to possible time-varying confounding, and three studies measuring depression symptoms were judged to be at critical risk of bias overall. There was also some evidence of funnel plot asymmetry. For these reasons, we rated our certainty in the estimates for anxiety as low, for depression as very low, and for mixed anxiety and depression as moderate. For the secondary outcomes, smoking cessation was associated with an improvement in symptoms of stress (SMD -0.19, 95% CI -0.34 to -0.04; 4 studies, 1792 participants; I2 = 50%), positive affect (SMD 0.22, 95% CI 0.11 to 0.33; 13 studies, 4880 participants; I2 = 75%), and psychological quality of life (SMD 0.11, 95% CI 0.06 to 0.16; 19 studies, 18,034 participants; I2 = 42%). There was also evidence that smoking cessation was not associated with a reduction in social quality of life, with the confidence interval incorporating the possibility of a small improvement (SMD 0.03, 95% CI 0.00 to 0.06; 9 studies, 14,673 participants; I2 = 0%). The incidence of new mixed anxiety and depression was lower in people who stopped smoking compared with those who continued (OR 0.76, 95% CI 0.66 to 0.86; 3 studies, 8685 participants; I2 = 57%), as was the incidence of anxiety disorder (OR 0.61, 95% CI 0.34 to 1.12; 2 studies, 2293 participants; I2 = 46%). We deemed it inappropriate to present a pooled estimate for the incidence of new cases of clinical depression, as there was high statistical heterogeneity (I2 = 87%).

AUTHORS' CONCLUSIONS

Taken together, these data provide evidence that mental health does not worsen as a result of quitting smoking, and very low- to moderate-certainty evidence that smoking cessation is associated with small to moderate improvements in mental health.  These improvements are seen in both unselected samples and in subpopulations, including people diagnosed with mental health conditions. Additional studies that use more advanced methods to overcome time-varying confounding would strengthen the evidence in this area.

Modeling smoking-attributable mortality among adults with major depression in the United States

Tobacco-related health disparities disproportionately affect smokers with major depression (MD). Although tobacco simulation models have been applied to general populations, to date they have not considered populations with a comorbid mental health condition. We developed and calibrated a simulation model of smoking and MD comorbidity for the US adult population using the 2005-2018 National Surveys on Drug Use and Health. We use this model to evaluate trends in smoking prevalence, smoking-attributable mortality and life-years lost among adults with MD, and changes in smoking prevalence by mental health status from 2018 to 2060. The model integrates known interaction effects between smoking initiation and cessation, and MD onset and recurrence. We show that from 2018 to 2060, smoking prevalence will continue declining among those with current MD. In the absence of intervention, people with MD will be increasingly disproportionately affected by smoking compared to the general population; our model shows that the smoking prevalence ratio between those with current MD and those without a history of MD increases from 1.54 to 2.42 for men and from 1.81 to 2.73 for women during this time period. From 2018 to 2060, approximately 484,000 smoking-attributable deaths will occur among adults with current MD, leading to 11.3 million life-years lost. Ambitious tobacco control efforts could alter this trajectory. With aggressive public health efforts, up to 264,000 of those premature deaths could be avoided, translating into 7.5 million life years gained. This model can compare the relative health gains across different intervention strategies for smokers with MD.

Applying Causal Inference Methods in Psychiatric Epidemiology: A Review

Importance

Associations between putative risk factors and psychiatric and substance use disorders are widespread in the literature. Basing prevention efforts on such findings is hazardous. Applying causal inference methods, while challenging, is central to developing realistic and potentially actionable etiologic models for psychopathology.

Observations

Causal methods can be divided into randomized clinical trials (RCTs), natural experiments, and statistical models. The first 2 approaches can potentially control for both known and unknown confounders, while statistical methods control only for known and measured confounders. The criterion standard, RCTs, can have important limitations, especially regarding generalizability. Furthermore, for ethical reasons, many critical questions in psychiatric epidemiology cannot be addressed by RCTs. We review, with examples, methods that try to meet as-if randomization assumptions, use instrumental variables, or use pre-post designs, regression discontinuity designs, or co-relative designs. Each method has strengths and limitations, especially the plausibility of as-if randomization and generalizability. Of the large family of statistical methods for causal inference, we examine propensity scoring and marginal models, which are best applied to samples with strong predictors of risk factor exposure.

Conclusions and Relevance

Causal inference is important because it informs etiologic models and prevention efforts. The view that causation can be definitively resolved only with RCTs and that no other method can provide potentially useful inferences is simplistic. Rather, each method has varying strengths and limitations. We need to avoid the extremes of overzealous causal claims and the cynical view that potential causal information is unattainable when RCTs are infeasible. Triangulation, which applies different methods for elucidating causal inferences to address to the same question, may increase confidence in the resulting causal claims.

The relationship between smoking cessation and binge drinking, depression, and anxiety symptoms among smokers with serious mental illness

INTRODUCTION

Concerns about the adverse effects of smoking cessation on alcohol use and mental health are a barrier to cessation for smokers with serious mental illness (SMI). The purpose of this study is to examine how incident smoking cessation affects binge drinking and symptoms of depression and anxiety among smokers with SMI.

METHODS

The present study is a secondary analysis of the OPTIN trial, which demonstrated the effectiveness of proactive outreach for smoking cessation among Minnesota Health Care Programs enrollees. Participants with ICD-9 codes indicating schizophrenia spectrum disorders, psychotic disorders, bipolar disorders, or severe/recurrent major depressive disorder were categorized as having SMI (n = 939); remaining smokers were categorized as non-SMI (n = 1382). Multivariable regressions modeled the association between incident smoking cessation and binge drinking, PHQ-2 depression scores, and PROMIS anxiety scores in the two groups.

RESULTS

Quitting smoking was not associated with binge drinking among those with SMI, but was associated with less binge drinking among those without SMI (p = 0.033). Quitting smoking was not associated with PHQ-2 depression scores among those with or without SMI. However, quitting smoking was associated with lower mean PROMIS anxiety scores for those with SMI (p = 0.031), but not those without SMI.

CONCLUSION

Quitting smoking was not associated with heightened binge drinking or symptoms of depression and anxiety among smokers with SMI. These findings suggest that quitting smoking is not detrimental for these patients, and provide evidential support for facilitating access to cessation resources for patients with serious mental illness who smoke.

Reassessing the importance of 'lost pleasure' associated with smoking cessation: implications for social welfare and policy

INTRODUCTION

Benefit-cost analyses of tobacco regulations include estimates of the informed choice of smokers to continue smoking. Few studies have focused on subjective feelings associated with continued smoking. This study estimates how smoker discontent and regret relate to risk perceptions and health concerns.

METHODS

We analysed data from a 2015 nationally representative, online survey of 1284 US adult current smokers. Information was collected on regret, intention to quit, perceived addiction, risk perceptions and health concerns. Multivariate logistic regression adjusting for sociodemographics and health status was used to examine factors associated with smoker discontent.

RESULTS

More than 80% of current smokers report high (22.5%) or very high (59.8%) discontent due to inability to quit, perceived addiction and regret about having started to smoke. Higher levels of discontent did not vary significantly by sex, age, race/ethnicity, education or income (adjusted odds ratios (AORs) 0.5-1.2). Compared with the smokers expressing low (5.9%) or very low (3.6%) discontent, those expressing higher levels of discontent perceived their health status as fair/poor (AOR=2.3), worried most of the time about lung cancer (AOR=4.6) and felt they were more likely to develop lung cancer in the future (AOR=5.1).

CONCLUSION

The proportion of smokers who might be characterised as having a preference to continue smoking are greatly outnumbered by addicted, discontent and concerned smokers who want to quit and regret ever having started to smoke. These discontent smokers could have a substantial net welfare gain if new regulations helped them escape their concerns about the health effects from continuing smoking.