ADHD and smoking: from genes to brain to behavior

Deep sequencing of candidate genes identified 14 variants associated with smoking abstinence in an ethnically diverse sample

Despite the large public health toll of smoking, genetic studies of smoking cessation have been limited with few discoveries of risk or protective loci. We investigated common and rare variant associations with success in quitting smoking using a cohort from 8 randomized controlled trials involving 2231 participants and a total of 10,020 common and 24,147 rare variants. We identified 14 novel markers including 6 mapping to genes previously related to psychiatric and substance use disorders, 4 of which were protective (CYP2B6 (rs1175607105), HTR3B (rs1413172952; rs1204720503), rs80210037 on chr15), and 2 of which were associated with reduced cessation (PARP15 (rs2173763), SCL18A2 (rs363222)). The others mapped to areas associated with cancer including FOXP1 (rs1288980) and ZEB1 (rs7349). Network analysis identified significant canonical pathways for the serotonin receptor signaling pathway, nicotine and bupropion metabolism, and several related to tumor suppression. Two novel markers (rs6749438; rs6718083) on chr2 are flanked by genes associated with regulation of bodyweight. The identification of novel loci in this study can provide new targets of pharmacotherapy and inform efforts to develop personalized treatments based on genetic profiles.

The associations of secondhand smoke exposure with neurodevelopmental disorders and critical time window identification: A systematic review and meta-analysis

BACKGROUND

Secondhand smoke (SHS) exposure was harmful for brain development. However, the association between SHS exposure and NDDs diagnosis were unclear.

OBJECTIVES

To evaluate associations between SHS exposure and NDDs diagnosis, identify critical time windows, and summarize the strength of evidence.

METHODS

To investigate the associations of SHS exposure and the development of NDDs, we searched Ovid, EMBASE, Web of Science, Cochrane Library, and PubMed for all the relevant studies up to 31 March 2023. The risk estimates and standardized mean differences (SMD) for the individuals with any NDDs who were exposed to SHS exposure compared with those unexposed or low-exposed.

RESULTS

The results showed that a total of 31,098 citations were identified, of which 54 studies were included. We identified significant associations between SHS exposure and the risks of NDDs including specific types of NDDs like attention deficit hyperactivity disorder (ADHD) and learning disabilities (LD) despite the observed heterogeneity for NDDs and ADHD. We also observed a significant association between cotinine exposure and ADHD. However, inconsistent ratings between the two quality-of-evidence methods for all the meta-analyses indicated the current evidence of the associations and the potential exposure window remained inconclusive.

DISCUSSION

Our findings suggested that SHS exposure was associated with a higher risk of developing ADHD and LD, with inconclusive quality-of-evidence. In addition, period-specific associations remained unclear based on current evidence.

Prevalence of current smoking and association with meeting 24-h movement guidelines: Results from a national convenience sample of autistic adults

LAY ABSTRACT

Cigarette smoking is a leading risk behavior for cardiovascular disease; yet its prevalence and determinants are not clear in autistic adults. We examined the prevalence of current smoking and its association between meeting 24-h movement (i.e. sleep, physical activity, and sedentary behavior) guidelines in a self-selecting convenience sample of 259 autistic adults in the United States. We found that current smokers met fewer 24-h movement guidelines. Most significant, those who had insufficient sleep and those with high levels of sedentary behavior were more likely to be current smokers. Therefore, targeting these movement behaviors may be potential intervention targets for smoking cessation.

Substance Use and Educational Impacts in Youth With and Without Chronic Illness

INTRODUCTION

Alcohol, cannabis, and nicotine are commonly used psychoactive substances that affect adolescent neurocognition. Little is known about the educational impacts of their use on measures of educational performance, participation and problems, especially among youth with a chronic illness who may use these substances to alleviate stress and symptoms.

METHODS

Adolescents receiving general or subspecialty care were administered an electronic survey from 2016 to 2018. Data were analyzed in 2023. Using modified Poisson models, cross-sectional associations between past 12-month usage of alcohol, cannabis, and/or nicotine and educational impacts were estimated.

RESULTS

Among 958 adolescents (mean age 16.0 years (SD 1.3), 564 (58.9%) female gender, 445 (46.5%) in subspecialty care), 294 (30.7%), 220 (23.0%), and 126 (13.2%) reported past 12-month use of alcohol, cannabis, and nicotine respectively, while 407 (42.5%) reported ≥1 educational impact, including recent lower grades 210 (21.9%), past 3-month truancy from school 164 (17.1%) or activities 170 (17.7%), and detention 82 (8.6%). Use of cannabis, but not other substances, was associated with negative educational impacts: lower grades (mostly C's/D's/F's), adjusted prevalence ratios [APR, (95% CI)] 1.54 (1.13-2.11); past 3-month truancy from school [2.16 (1.52-3.07)]; detention [2.29 (1.33-3.94)]. The association between cannabis use and any negative educational impact was stronger among adolescents with a chronic illness (p<0.001).

CONCLUSIONS

Among adolescents, cannabis use was associated with a heightened risk of negative educational impacts, even after controlling for alcohol and nicotine use. Adolescents with chronic illness were especially likely to experience negative educational impacts. Findings underscore need for preventive interventions and messaging to reduce risks.

Toward an Increased Attention on ADHD Symptoms and Traits in Young Adults: Prevalence Data From Screening Tools in a Psychiatric Outpatient Clinic

OBJECTIVE

to analyze the prevalence of ADHD symptoms and traits in a heterogeneous clinical psychiatric sample of young adults (aged 18-24 years old), who referred to a specialized outpatient clinic for various psychiatric and psychological disturbances.

METHOD

259 participants completed three validated self-report screening questionnaires for ADHD: the Wender Utah Rating Scale (WURS), the Adult Attention-Deficit/Hyperactivity Disorder Self-Report Screening Scale for DSM-5 (ASRS-5), and the Conners' adult ADHD rating scale (CAARS).

RESULTS

12.4% of our sample scored above the cut-off at both the WURS and the ASRS-5 and was considered at risk of ADHD.

CONCLUSION

the prevalence rate in our sample is higher than the one found in the adult general population (6.76%), and in the lower range of the one found in the adult clinical population (6.9%-38.8%). The potential role of sociodemographic (age, sex, gender identity, and employment) and comorbidity factors is discussed.

Cardiovascular risk in adults with Delayed Sleep Phase Syndrome (DSPS) and Attention-Deficit/Hyperactivity Disorder (ADHD)

TRIAL REGISTRATION

FASE, https://www.trialregister.nl/, #NTR3831.

The interaction of e-cigarette use and mental health symptoms on risk of cigarette smoking initiation among young adults in the United States

BACKGROUND AND AIMS

It is unknown whether young adults who vape nicotine and have poor mental health have greater risk of smoking initiation than expected based on individual risks of vaping and mental health alone. This study aimed to estimate the joint association of vaping and mental health symptoms with smoking initiation among young adults, and test for additive interaction between vaping and mental health in smoking initiation risk.

DESIGN

Using five waves of the Population Assessment of Tobacco and Health (wave 1, 2013-2014; wave 2, 2014-2015; wave 3, 2015-2016; wave 4, 2016-2018; wave 5, 2018-2019), we estimated risk differences (RD) for the association of time-varying and time-lagged vaping and internalizing (e.g., anxiety, depressive) and externalizing (e.g., inattention/hyperactivity) mental health symptoms with cigarette smoking initiation at follow-up, over four 1-year intervals. We calculated interaction contrasts (IC) to estimate the excess risk of smoking initiation attributable to the interaction of vaping and mental health symptoms.

SETTING

United States.

PARTICIPANTS

A total of 6908 cigarette-naïve individuals aged 18-24 years.

MEASUREMENTS

Exposures included current (past-30 day) vaping and internalizing and externalizing mental health symptoms (high vs moderate/low symptoms). The outcome was smoking initiation (ever cigarette use) after 1 year.

FINDINGS

The per-interval risk of smoking initiation was 7.6% (1039 cases/13 712 person-intervals). Compared with noncurrent vaping and moderate/low mental health symptoms, adjusted RDs for current vaping and high mental health symptoms were 17.2% (95% confidence interval [CI]: 7.2% to 27.3%) for internalizing and 18.7% (95%CI: 8.1% to 29.2%) for externalizing symptoms. The excess risk attributed to interaction of current vaping and high externalizing symptoms was IC = 11.3% (95%CI: 1.3% to 21.2%; P = 0.018), with inconclusive findings for internalizing symptoms (IC = 7.7% [95%CI: -2.2% to 17.7%; P = 0.097]).

CONCLUSIONS

There is possible, but inconclusive, superadditivity between vaping and mental health in risk of smoking initiation among young adults in the United States.

Attention-deficit/hyperactivity disorder is associated with increased risk of cardiovascular diseases: A systematic review and meta-analysis

Attention-deficit/hyperactivity disorder (ADHD) often co-occurs with other psychiatric and physical diseases. However, available evidence on associations between ADHD and cardiovascular diseases (CVDs) is mixed. To systematically review, quantitatively synthesize, and appraise available evidence on the link between ADHD with CVDs, we searched relevant articles in PubMed, Embase, PsycINFO, and Web of Science from inception to May 1, 2022. Study quality was assessed by using the Newcastle-Ottawa Scale, and random-effects model meta-analyses were performed. A total of 18,391,169 (ADHD: n = 421,224) individuals from 11 studies were included in our systematic review and 8,196,648 (ADHD = 332,619) individuals from five studies were included in the main meta-analysis of adjusted estimates. Pooled estimates showed that ADHD was significantly associated with an increased risk of CVDs in analyses based on adjusted effect size (odds ratio (OR) = 1.96; 95% confidence interval (CI) = 1.19-2.23, Q = 140.74, P Q < 0.001, I 2 = 97.2%). When restricted among adults, the heterogeneity declined to null (OR = 1.73; 95% CI = 1.14-2.62, Q = 6.28, P Q = 0.10, I 2 = 6.28%), suggesting age might be the main source of heterogeneity. In subgroup analyses, we found increased risk of CVDs associated with ADHD across age groups, type of CVDs, and data sources. This systematic review and meta-analyses indicate that ADHD is associated with increased risk for CVDs, but further studies with various study designs are warranted to advance the understanding of the underlying mechanisms for the observed association between ADHD and CVDs. Additional research is also needed to resolve the role of ADHD medications which remains unclear due to the limited number of primary studies exploring this issue.

Association of ADHD symptoms with type 2 diabetes and cardiovascular comorbidities in adults receiving outpatient diabetes care

Background

The relationship between attention-deficit/hyperactivity disorder (ADHD) symptoms and type 2 diabetes mellitus (T2D) and its cardiovascular outcomes have not been sufficiently studied.

Methods

2,986 adults with T2D from the Joslin Diabetes Center at Upstate Medical University were assessed for ADHD-like symptoms, executive dysfunction, and emotional control using the Adult Self-Report Scale V1.1 (ASRS) expanded version. Surveys were sent electronically, and clinical data were obtained from the electronic medical record. Pearson chi-square test was used for categorical variables association. When ASRS scores were the dependent variable, negative binomial regression correcting for demographic variables that were associated with the ASRS scores was used.

Results

155 (49.2%) of respondents met DSM-5 criteria for ADHD using the ASRS scores; Only ten (3.6%) of respondents had an ICD10 diagnosis of ADHD in their medical record; Forty-three (13.7%) had either a diagnosis of ADHD in the medical history or were taking medications used by people with ADHD. Higher levels of ADHD-like symptoms were found in patients with T2D compared with population norms. There was a modest association of the ASRS executive dysfunction subscale with overall cardiovascular comorbidities (p = 0.03). However, the p-value did not survive the multiple testing correction. Both ADHD-like symptoms and symptoms associated with emotional control, however, were not associated with specific cardiovascular diseases, hypertension, or with HbA1c, LDL-cholesterol, triglycerides, ALT, creatinine, or eGFR.

Conclusion

Our results suggest that adults with T2D attending a tertiary care diabetes clinic are at risk for having ADHD-like symptoms, highlighting the importance of screening for ADHD symptoms in this specialty setting and referring undiagnosed adult patients for further assessment and treatment of ADHD. Larger studies are needed to clarify the relationship between ADHD-like symptoms, executive dysfunction, and emotional control with diabetic control and comorbidities.

An Examination of the Role of Sluggish Cognitive Tempo as a Moderator of the Relationship Between ADHD and Nicotine Use

OBJECTIVE

ADHD is a neurodevelopmental disorder characterized by executive dysfunction and functional impairments including nicotine consumption. Sluggish cognitive tempo (SCT) has been associated with ADHD and posited as an independent construct. The present study hypothesized that SCT would moderate the relationships between ADHD and nicotine-related behaviors.

METHOD

Participants (n = 309) were recruited using Mechanical Turk and completed measures of ADHD symptoms, SCT, and smoking history.

RESULTS

ADHD was associated with age of initiation of smoking and more severe withdrawal symptoms for both combustible and electronic cigarettes. SCT significantly moderated the relationship between ADHD and withdrawal symptom severity (both electronic and combustible cigarettes).

CONCLUSION

The results of the present study suggest that SCT plays an important role in the complex relationship between ADHD and smoking withdrawal. Future research should further explore the construct of SCT to better understand its role in psychopathology and intervention strategies.

Neuroeconomic predictors of smoking cessation outcomes: A preliminary study of delay discounting in treatment-seeking adult smokers

Large proportions of smokers are unsuccessful in evidence-based smoking cessation treatment and identifying prognostic predictors may inform improvements in treatment. Steep discounting of delayed rewards (delay discounting) is a robust predictor of poor smoking cessation outcome, but the underlying neural predictors have not been investigated. Forty-one treatment-seeking adult smokers completed a functional magnetic resonance imaging (fMRI) delay discounting paradigm prior to initiating a 9-week smoking cessation treatment protocol. Behavioral performance significantly predicted treatment outcomes (verified 7-day abstinence, n = 18; relapse, n = 23). Participants in the relapse group exhibited smaller area under the curve (d = 1.10) and smaller AUC was correlated with fewer days to smoking relapse (r = 0.56, p < 0.001) Neural correlates of discounting included medial and dorsolateral prefrontal cortex, posterior cingulate, precuneus and anterior insula, and interactions between choice type and relapse status were present for the dorsolateral prefrontal cortex, precuneus and the striatum. This initial investigation implicates differential neural activity in regions associated with frontal executive and default mode activity, as well as motivational circuits. Larger samples are needed to improve the resolution in identifying the neural underpinnings linking steep delay discounting to smoking cessation.

A network approach to substance use, internalizing, and externalizing comorbidity in U.S. adults

INTRODUCTION

Use of conventional cigarettes (CIG), alcohol, marijuana, and sedatives [i.e., benzodiazepines and barbiturates]) commonly co-occur with internalizing and externalizing disorders. It is unclear how these relationships extend to electronic cigarettes (ECIGs) and prescription drugs not prescribed (i.e., sedatives, tranquilizers, and painkillers [PDNP]), and whether they differ by gender.

METHODS

Adult data (N = 30,211) from Wave 1 (2013-2014) of the Population Assessment of Tobacco and Health Study were used to estimate a network of current or past-month use for six substances, experiencing four internalizing symptoms in the past month, and experiencing seven externalizing symptoms in the past month. Visual comparisons, global strength invariance, network structure invariance, and edge strength invariance were tested to detail substance use and internalizing/externalizing symptom networks.

RESULTS

Overall, networks were consistent between men and women. The strongest substance use/mental health symptom connections estimated as edge-weights (EW) were between marijuana with lying (EW = 0.60, 95% CI = 0.49; 0.70), marijuana with engaging in fights (EW = 0.54, 95% CI = 0.27; 0.81), PDNP with having trouble sleeping (EW = 0.53, 95% CI = 0.40; 0.66), and alcohol and impulsivity (EW = 0.48, 95% CI = 0.42; 0.53).

DISCUSSION

There were many weak connections throughout the substance use and internalizing/externalizing network. A few important connections were identified and encourage future study. In particular, PDNP was most strongly associated with internalizing symptoms. Marijuana, alcohol and PDNP use were most strongly associated with externalizing symptoms.

Smoking cessation among people with mental illness: A South African perspective

Tobacco use is recognised as a serious, worldwide public health concern. Smoking cessation is of great interest across a wide range of medical specialities, including family medicine. However, smoking cessation among people with mental illness (PWMI) has attracted scant attention in South African literature. This is despite PWMI suffering disproportionately from the damages of tobacco. The harms of smoking are not limited to physical health but extend to mental health. This article discusses the need for multifaceted smoking cessation treatments for PWMI in the public health sector, taking into consideration the prevalence and unique drivers of smoking in this population. A brief overview of patterns of tobacco use, associated harms and smoking cessation interventions in South Africa is given; all within the context of mental illness.

Smoking remains associated with education after controlling for social background and genetic factors in a study of 18 twin cohorts

We tested the causality between education and smoking using the natural experiment of discordant twin pairs allowing to optimally control for background genetic and childhood social factors. Data from 18 cohorts including 10,527 monozygotic (MZ) and same-sex dizygotic (DZ) twin pairs discordant for education and smoking were analyzed by linear fixed effects regression models. Within twin pairs, education levels were lower among the currently smoking than among the never smoking co-twins and this education difference was larger within DZ than MZ pairs. Similarly, education levels were higher among former smoking than among currently smoking co-twins, and this difference was larger within DZ pairs. Our results support the hypothesis of a causal effect of education on both current smoking status and smoking cessation. However, the even greater intra-pair differences within DZ pairs, who share only 50% of their segregating genes, provide evidence that shared genetic factors also contribute to these associations.

Modelling Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) Using Mice and Zebrafish

Autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD) are two debilitating neurodevelopmental disorders. The former is associated with social impairments whereas the latter is associated with inattentiveness, hyperactivity, and impulsivity. There is recent evidence that both disorders are somehow related and that genes may play a large role in these disorders. Despite mounting human and animal research, the neurological pathways underlying ASD and ADHD are still not well understood. Scientists investigate neurodevelopmental disorders by using animal models that have high similarities in genetics and behaviours with humans. Mice have been utilized in neuroscience research as an excellent animal model for a long time; however, the zebrafish has attracted much attention recently, with an increasingly large number of studies using this model. In this review, we first discuss ASD and ADHD aetiology from a general point of view to their characteristics and treatments. We also compare mice and zebrafish for their similarities and discuss their advantages and limitations in neuroscience. Finally, we summarize the most recent and existing research on zebrafish and mouse models of ASD and ADHD. We believe that this review will serve as a unique document providing interesting information to date about these models, thus facilitating research on ASD and ADHD.

Smoking During Pregnancy and Risk of Attention-deficit/Hyperactivity Disorder in the Third Generation

BACKGROUND

Animal experiments indicate that environmental factors, such as cigarette smoke, can have multigenerational effects through the germline. However, there are little data on multigenerational effects of smoking in humans. We examined the associations between grandmothers' smoking while pregnant and risk of attention-deficit/hyperactivity disorder (ADHD) in her grandchildren.

METHODS

Our study population included 53,653 Nurses' Health Study II (NHS-II) participants (generation 1 [G1]), their mothers (generation 0 [G0]), and their 120,467 live-born children (generation 2 [G2]). In secondary analyses, we used data from 23,844 mothers of the nurses who were participants in the Nurses' Mothers' Cohort Study (NMCS), a substudy of NHS-II.

RESULTS

The prevalence of G0 smoking during the pregnancy with the G1 nurse was 25%. ADHD was diagnosed in 9,049 (7.5%) of the grandchildren (G2). Grand-maternal smoking during pregnancy was associated with increased odds of ADHD among the grandchildren (adjusted odds ratio [aOR] = 1.2; 95% confidence interval [CI] = 1.1, 1.2), independent of G1 smoking during pregnancy. In the Nurses' Mothers' Cohort Study, odds of ADHD increased with increasing cigarettes smoked per day by the grandmother (1-14 cigarettes: aOR = 1.1; 95% CI = 1.0, 1.2; 15+: aOR = 1.2; 95% CI = 1.0, 1.3), compared with nonsmoking grandmothers.

CONCLUSIONS

Grandmother smoking during pregnancy is associated with an increased risk of ADHD among the grandchildren.

Smoking-Specific Risk Factors in Early Adulthood That Mediate Risk of Daily Smoking by Age 29 for Children with ADHD

OBJECTIVE

To test whether smoking-specific risk factors in early adulthood mediate prediction to daily smoking from childhood ADHD.

METHODS

Participants were 237 with and 164 without childhood ADHD. A smoking risk profile score comprising smoking-specific factors measured between ages 18 to 25 (e.g., craving severity) and age of initiation was tested as mediator of the association between childhood ADHD and age 29 daily smoking.

RESULTS

Childhood ADHD predicted age 29 smoking (β = -.15, p = .019), 35% of ADHD versus 17% of nonADHD, and the profile score (β = -.07, p = .004), which in turn mediated prediction to age 29 daily smoking (β = -.03; p = .007). When tested individually, three profile variables (# cigarettes/day, difficulty concentrating during abstinence, and nicotine dependence) were significant mediators (ps = 0.005-0.038), above and beyond early adult smoking, ADHD persistence, and delinquency.

CONCLUSIONS

These behavioral smoking characteristics help explain later daily cigarette smoking for adults with ADHD histories and may need to be targeted in intervention.

Investigating genetic correlation and causality between nicotine dependence and ADHD in a broader psychiatric context

People with attention-deficit/hyperactivity disorder (ADHD) or other psychiatric disorders show high rates of nicotine dependence (ND). This comorbidity might be (partly) explained by shared genetic factors. Genetic correlations between ND and ADHD (or other psychiatric disorders) have not yet been estimated. A significant genetic correlation might indicate genetic overlap, but could also reflect a causal relationship. In the present study we investigated the genetic correlation (with LD score regression analyses) between ND and ADHD, as well as between ND and other major psychiatric conditions (major depressive disorder, schizophrenia, anxiety, bipolar disorder, autism spectrum, anorexia nervosa, and antisocial behavior) based on the summary statistics of large Genome Wide Association studies. We explored the causal nature of the relationship between ND and ADHD using two-sample Mendelian randomization. We found a high genetic correlation between ND and ADHD (r_g  = .53, p = 1.85 × 10^-13 ), and to a lesser extent also between ND-major depressive disorder (r_g  = .42, p = 3.6 × 10^-11 ) and ND-schizophrenia (r_g  = .18, p = 1.1 × 10^-3 ). We did not find evidence for a causal relationship from liability for ADHD to ND (which could be due to a lack of power). The strong genetic correlations might reflect different phenotypic manifestations of (partly) shared underlying genetic vulnerabilities. Combined with the lack of evidence for a causal relationship from liability for ADHD to ND, these findings stress the importance to further investigate the underlying genetic vulnerability explaining co-morbidity in psychiatric disorders.

The association between internalizing and externalizing severity with current use of cigarettes, e-cigarettes, and alcohol in adults: Wave 1 of the Population Assessment of Tobacco and Health (PATH) study

INTRODUCTION

Concurrent tobacco/alcohol use is common in adults, and associated with the severity of symptoms experienced by those with mental health disorders. However, few studies have explored this relationship across different combinations of tobacco products [i.e., conventional cigarette (CC) and electronic cigarette (EC)] and alcohol.

METHODS

Data from the Wave 1 (2013-2014) Population Assessment of Tobacco and Health study were used. A total of 15,947 adults aged 18 years or older with complete study information were included. Multinomial logistic regression analyses were performed to determine the relationship between lifetime internalizing/externalizing severity and past 30-day use of tobacco and alcohol, adjusting for nicotine dependence (ND), sex, age, race, education, and income.

RESULTS

Internalizing severity was more strongly associated with CC and alcohol use (moderate AOR = 1.47, 95% CI = 1.22-1.77; high AOR = 1.29, 95% CI = 1.03-1.61) as well as alcohol-exclusive use (moderate AOR = 1.58, 95% CI = 1.27-1.96; high AOR = 1.31, 95% CI = 1.05-1.64) while externalizing severity was more strongly associated with EC and alcohol use (high AOR = 2.97, 95% CI = 1.84-4.81, moderate AOR = 2.29, 95% CI = 1.53-3.43) when accounting for ND compared to none. The relationship between externalizing severity with EC use was dependent on alcohol being used with EC.

CONCLUSIONS

The associations between psychopathology (internalizing vs. externalizing severity) varies by different combinations of alcohol, CC, and EC. Further, these relationships may be mediated through ND. Future investigations into the comorbidity between mental disorder symptoms with tobacco and alcohol use should consider use of specific substances as well as their combination.

Using e-diaries to investigate ADHD - State-of-the-art and the promising feature of just-in-time-adaptive interventions

Attention-deficit/hyperactive disorder (ADHD) is characterized by symptoms which are dynamic in nature: states of hyperactivity, inattention and impulsivity as core symptoms, and emotion dysregulation as associated feature. Although tremendous work has been done to investigate between-subject differences (how patients with ADHD differ from healthy controls or patients with other disorders), little is known about the relationship between symptoms with triggers and contexts, that may allow us to better understand their causes and consequences. Understanding the temporal associations between symptoms and environmental triggers in an ecologically valid manner may be the basis to developing just-in-time adaptive interventions. Fortunately, recent years have seen advances in methodology, hardware and innovative statistical approaches to study dynamic processes in daily life. In this narrative review, we provide a description of the methodology (ambulatory assessment), summarize the existing literature in ADHD, and discuss future prospects for these methods, namely mobile sensing to assess contextual information, real-time analyses and just-in-time adaptive interventions.

Smoking and Long-Term Sick Leave in a Japanese Working Population: Findings of the Japan Epidemiology Collaboration on Occupational Health Study

Background

Few studies have investigated the association between tobacco smoking and sick leave (SL) in Japan.

Methods

We followed 70 896 workers aged 20–59 years (60 133 males, 10 763 females) between April 2012 and March 2017. A Cox proportional hazards model was used to investigate the associations between smoking (smoking status and intensity) and long-term SL (ie, SL lasting ≥30 consecutive days). Cause-specific analyses were also conducted.

Results

A total of 1777 people took long-term SL during a follow-up of 307 749 person years. Compared with never-smokers, current smokers were at a higher risk of long-term SL (hazard ratio [HR] = 1.32; 95% confidence interval [CI] = 1.19 to 1.48). Cause-specific analyses revealed that current smoking was associated with a higher risk of SL due to all physical disorders (HR = 1.44, 95% CI = 1.22 to 1.69), cancer (HR = 1.49, 95% CI = 1.10 to 2.01), cardiovascular disease (CVD; HR = 2.16, 95% CI = 1.31 to 3.55), and injuries/external causes (HR = 1.83, 95% CI = 1.31 to 2.58). Former smokers were at a higher risk of SL due to cancer at a borderline significance level (HR = 1.38, 95% CI = 0.99 to 1.92). Low-intensity smoking (ie, 1–10 cigarettes smoked per day) was associated with all-cause SL, SL due to CVD, and SL due to injuries/external causes compared with never-smokers.

Conclusion

In a large cohort of working-age Japanese, smoking was associated with a greater risk of long-term SL. Greater effort is needed to mitigate disease burden associated with smoking at workplace in Japan.

Implications

Our study contributes to the literature on the association between smoking and SL in several ways. First, the study was conducted among a Japanese working population. While the association has been extensively studied in Western setting, few attempts have been made elsewhere. Second, cause-specific analyses were undertaken in our study. Third, we paid attention to the effect of low-intensity smoking on SL given that there is growing evidence of an elevated health risk associated with low-intensity smoking.

ASRS Questionnaire and Tobacco Use: Not Just a Cigarette. A Screening Study in an Italian Young Adult Sample

Young adults exhibit greater sensitivity than adults to nicotine reinforcement, and Attention Deficit Hyperactivity Disorder (ADHD) increases the risk for early-onset smoking. We investigated the correlation between ADHD Self-Report Scale (ASRS) scores and smoking, evaluated the prevalence of ADHD symptomatology (not diagnoses) in smokers and non-smokers and its comorbidity with benzodiazepine and gambling addictions. A total of 389 young adults from 14 schools in Northern Italy fill out a survey and the Adult ADHD Self-Report Scale (ASRS). A total of 15.2% of subjects tested positive at the ASRS, which correlated with smoking; moreover, smokers had twice the probability of testing positive at the ASRS. ADHD symptomatology, especially when comorbid with tobacco abuse, is an important condition to monitor because early nicotine exposure could be a gateway for other addictive behaviors.

Proinflammatory mediators and their associations with medication and comorbid traits in children and adults with ADHD

Peripheral immune activation can influence neurodevelopment and is increased in autism, but is less explored in attention deficit hyperactivity disorder (ADHD). Patients with ADHD often display comorbid autism traits and gastrointestinal (GI) symptoms. Plasma protein levels of two acute phase reactants, C-reactive protein (CRP) and serum amyloid A (SAA), and two endothelial adhesion molecules, soluble intercellular adhesion molecule 1 (sICAM-1) and soluble vascular cell adhesion molecule 1 (sVCAM-1), which share important roles in inflammation, were analyzed in 154 patients with ADHD and 61 healthy controls. Their associations with ADHD diagnosis, severity, medication and comorbid autistic symptoms, emotion dysregulation and GI symptoms were explored. The ADHD patients had increased levels of sICAM-1 and sVCAM-1 compared to healthy controls (p = 8.6e-05, p = 6.9e-07, respectively). In children with ADHD, the sICAM-1 and sVCAM-1 levels were higher among those with ADHD medication than among children (p = 0.0037, p = 0.0053, respectively) and adults (p = 3.5e-09, p = 1.9e-09, respectively) without ADHD medication. Among the adult ADHD patients, higher sICAM-1 levels were associated with increased comorbid autistic symptoms in the domains attention to detail and imagination (p = 0.0081, p = 0.00028, respectively), and higher CRP levels were associated with more GI symptoms (p = 0.014). sICAM-1 and sVCAM-1 levels were highly correlated with each other, and so were CRP and SAA levels. To conclude, vascular inflammatory activity may be overrepresented in ADHD, with elevated sICAM-1 and sVCAM-1 levels and this may in children be a consequence of current ADHD medication, and in adults relate to increased comorbid autistic symptoms. Replication is warranted.

Evaluation of causality between ADHD and Parkinson's disease: Mendelian randomization study

In a retrospective cohort study, patients with attention-deficit hyperactivity disorder (ADHD) and psychostimulant prescription were associated with increased risk of Parkinson's disease (PD). It is unclear whether ADHD per se or psychostimulant prescription is associated with PD. We aim to determine if genetic correlation or/and causal association exists between ADHD and PD using summary statistics obtained from the largest meta-analysis of genome-wide association studies of ADHD (20,183 cases; 35,191 controls) and PD (26,421 cases; 442,271 controls). Genetic correlation was tested between ADHD and PD by linkage disequilibrium score regression. Causal estimate was assessed by inverse-variance weighted (IVW) method as the main mendelian randomization analysis, with sensitivity analyses to detect horizontal pleiotropy. Weak and inverse genetic correlation existed between ADHD and PD (r=-0.100;SE=0.045;P = 0.026). Univariable IVW analysis with 10 and 77 genetic instruments respectively revealed null association for ADHD with PD (OR=0.930 per doubling in odds of ADHD; 95% CI:0.792-1.092) and PD with ADHD (OR=0.986 per doubling in odds of PD; 95% CI:0.956-1.015). Multivariable IVW analyses adjusted for BMI/smoking also revealed null association of ADHD with PD. Using 58 PD-associated genetic instruments, multivariable IVW analysis with/without adjustment for BMI/smoking suggested a weak and inverse causal association for PD on ADHD, but cautious interpretation is required. This well-powered study did not support causality between ADHD and PD. The observed positive association between ADHD and PD is more likely to be caused by unmeasured confounders. As psychostimulant use is associated with high risk of early-onset PD, future research should focus on this area.

Sodium hydrogen exchanger 9 NHE9 (SLC9A9) and its emerging roles in neuropsychiatric comorbidity

Variations in SLC9A9 gene expression and protein function are associated with multiple human diseases, which range from Attention-deficit/hyperactivity disorder (ADHD) to glioblastoma multiforme. In an effort to determine the full spectrum of human disease associations with SLC9A9, we performed a systematic review of the literature. We also review SLC9A9's biochemistry, protein structure, and function, as well as its interacting partners with the goal of identifying mechanisms of disease and druggable targets. We report gaps in the literature regarding the genes function along with consistent trends in disease associations that can be used to further research into treating the respective diseases. We report that SLC9A9 has strong associations with neuropsychiatric diseases and various cancers. Interestingly, we find strong overlap in SLC9A9 disease associations and propose a novel role for SLC9A9 in neuropsychiatric comorbidity. In conclusion, SLC9A9 is a multifunctional protein that, through both its endosome regulatory function and its protein-protein interaction network, has the ability to modulate signaling axes, such as the PI3K pathway, among others.

Attention-deficit/hyperactivity disorder and smoking habits in pregnant women

Background

Attention-deficit/hyperactivity disorder (ADHD) has been associated with an increased risk of tobacco smoking, and more difficulties with smoking cessation compared to non-ADHD individuals. Women with ADHD may therefore show elevated rates of smoking during pregnancy.

Aims

To examine the association between ADHD and smoking habits among pregnant women in Sweden and Norway.

Methods

Women pregnant for the first time were identified in Sweden (n = 622,037), and Norway (n = 293,383), of which 1.2% (n = 7,444), and 1.7% (n = 4,951) were defined as having ADHD, respectively. Data on smoking habits were collected early and late in pregnancy.

Results

In Sweden, ADHD was associated with an increased risk of smoking early in pregnancy, adjusted risk ratio (adjRR) 2.69 (95% confidence interval, 2.58–2.81), and late in pregnancy, adjRR 2.95 (2.80–3.10). Similar findings were observed in the Norwegian data, early in pregnancy, adjRR 2.31 (2.21–2.40), and late in pregnancy, adjRR 2.56 (2.42–2.70). Women with ADHD were more likely to continue smoking during pregnancy, compared to women without ADHD, both in Sweden adjRR 1.13 (1.10–1.17), and in Norway, adjRR 1.16 (1.12–1.20). Having a sibling diagnosed with ADHD was associated with an increased risk of smoking early and late in pregnancy, in both Sweden and Norway.

Conclusions

Women with ADHD are considerably more likely to smoke early and late in (their first) pregnancy and are less likely to stop smoking between the two time points. Smoking, early and late in pregnancy, co-aggregates in families with ADHD. Smoking prevention and intervention programs should be targeted towards women with ADHD, specifically during their childbearing years, to ensure better mother and child outcomes.

The D2-family receptor agonist bromocriptine but, not nicotine, reverses NMDA receptor antagonist-induced working memory deficits in the radial arm maze in mice

Hypofunction of the NMDA receptor (NMDAr) may underlie cognitive deficits associated with schizophrenia and other psychiatric conditions including working memory (WM) impairments. Given that these deficits link closely to functional outcome, treatments remediating such deficits require identification. NMDAr hypofunction can be modeled via treatment with the antagonist MK-801. Hence, the present study determined whether cholinergic or dopaminergic agonists attenuate MK-801-induced WM deficits in mice. WM was assessed in male C57BL/6 mice trained on an automated 12-arm radial arm maze (RAM) paradigm, wherein rewards were delivered after the first but, not after subsequent entries into WM arms (8/12) and never delivered for entries into reference memory (RM) arms (4/12). Mice were then treated with MK-801 (vehicle or 0.3 mg/kg) and nicotine (vehicle, 0.03 or 0.30 mg/kg) in a cross-over design. After a 2-week washout, mice were then retested with MK-801 and the dopamine D₂-family receptor agonist bromocriptine (vehicle, 3 or 10 mg/kg). In both experiments, MK-801 reduced WM span and increased RM and WM error rates. Nicotine did not attenuate these deficits. In contrast, a bromocriptine/MK-801 interaction was observed on WM error rate, where bromocriptine attenuated MK-801 induced deficits without affecting MK-801-induced RM errors. Additionally, bromocriptine produced the main effect of slowing latency to collect rewards. Hence, while NMDAr hypofunction-induced deficits in WM was unaffected by nicotine, it was remediated by treatment with the dopamine D₂-family agonist bromocriptine. Future studies should determine whether selective activation of dopamine D₂, D₃, or D₄ receptors remediate this NMDAr hypofunction-induced WM deficit.

Attention Deficit Hyperactivity Disorder Increases Nicotine Addiction Severity in Adults Seeking Treatment for Substance Use Disorders: The Role of Personality Disorders

AIMS

To examine the role of attention deficit/hyperactivity disorder (ADHD) and impulsive personality disorders in nicotine addiction severity among treatment-seeking substance use disorder (SUD) patients.

METHODS

In a cross-sectional study, we examined data from the second International ADHD in Substance Use Disorders Prevalence Study (IASP-2) on 402 adults in SUD treatment from Puerto Rico, Hungary, and Australia using diagnostic interviews for ADHD, antisocial (ASP) and borderline (BPD) personality disorders, and the self-report Fagerström Test of Nicotine Dependence (FTND). We compared SUD patients with and without ADHD on nicotine addiction severity. We tested direct and indirect pathways from ADHD to nicotine addiction and mediation through ASP and BPD.

RESULTS

Overall, 81.4% of SUD patients reported current cigarette smoking. SUD patients with ADHD had higher FTND scores and smoked more cigarettes than those without ADHD, with an earlier onset and more years of smoking. ASP mediated the effect of ADHD on all aspects of nicotine addiction severity, whereas BPD did so only on some aspects of nicotine addiction severity.

CONCLUSIONS

SUD patients with comorbid ADHD show more severe nicotine addiction than those without, which is largely explained by comorbid impulsive personality disorders. In SUD patients, it is important to screen for adult ADHD and other psychiatric disorders, especially those with impulse control deficits such as ASP and BPD.

Smoking abstinence effects on emotion dysregulation in adult cigarette smokers with and without attention-deficit/hyperactivity disorder

BACKGROUND

Cigarette smoking is robustly associated with attention-deficit/hyperactivity disorder (ADHD), but little is known about psychological mechanisms accounting for this comorbid relationship. This study examined difficulties in emotion regulation, or emotion dysregulation, among adult cigarette smokers with and without ADHD. Emotion dysregulation was predicted to be higher in an ADHD group at screening and after 24 -h smoking abstinence compared to a non-ADHD group.

METHODS

Cigarette smokers with (n = 19) and without (n = 20) ADHD completed a screening visit, baseline visit, and two experimental visits: smoking as usual (i.e., smoking satiated) and after biochemically-verified 24 -h smoking abstinence (i.e., smoking abstinent). Three emotion dysregulation rating scales (two self-report and one clinician rated) were administered at the screening visit and experimental sessions. Experimental sessions also included two emotion dysregulation behavioral tasks.

RESULTS

The ADHD group scored higher on all three rating scales at screening (p's < .001). For experimental sessions, group (ADHD, non-ADHD) x condition (smoking satiated, smoking abstinence) interactions were not significant across measures. However, group main effects emerged indicating higher emotion dysregulation in the ADHD group across all measures (p's < .001). Main effects also emerged for experimental condition, but were more mixed across emotion dysregulation measures.

CONCLUSIONS

Emotion dysregulation was higher among adult smokers with ADHD and during smoking abstinence across diagnostic groups, suggesting that this malleable psychological mechanism plays a role in smoking both for those with and without ADHD-such findings can inform treatment and prevention efforts.

Associations of ADHD Symptoms With Smoking and Alternative Tobacco Product Use Initiation During Adolescence

Objective

Recently, use of alternative tobacco products, such as electronic cigarettes (e-cigarettes) and hookah (water-pipe tobacco), has increased among adolescents. It is unknown whether attention-deficit hyperactivity disorder (ADHD) symptoms are associated with initiation of alternative tobacco product use.

Methods

Ninth grade high school students who never used any tobacco product at baseline (N = 1,921) participated in a longitudinal survey from 2014 to 2015. Overall symptomatology and inattention (IN) and hyperactivity-impulsivity (HI) ADHD subtypes were assessed at baseline. Past 6-month e-cigarette, hookah, and combustible cigarette use (yes/no) were reported at three semi-annual follow-ups. Repeated measures logistic regression models assessed the association of baseline ADHD symptoms with likelihood of tobacco product initiation across follow-ups.

Results

For ADHD main effect estimates, unadjusted odds of reporting e-cigarette, hookah, and combustible cigarette use pooled across follow-up time points were 45%, 33%, and 37% greater, respectively, with each increase in one SD-unit of baseline ADHD symptoms in baseline never-users of tobacco products. ADHD was not associated with hookah or combustible cigarette use after adjusting for other risk factors. After adjustment, e-cigarette use initiation remained associated with overall ADHD (odds ratio, OR [95%confidence interval, 95% CI] = 1.22 [1.04, 1.42]) and HI (OR [95% CI] = 1.26 [1.09, 1.47]) symptoms, but not IN symptoms (OR [95% CI] = 1.13 [0.97, 1.32]). ADHD × Time interactions were not significant, suggesting ADHD increased odds of e-cigarette use initiation but did not alter the shape of use trajectory across follow-up among initiators.

Conclusions

Understanding the psychosocial mechanisms underlying the pathway from ADHD to e-cigarette use may advance tobacco product use etiologic theory and prevention practice in the current era in which e-cigarette use is popular among youth.

Anxiety Sensitivity Physical and Cognitive Concerns in Relation to Smoking-oriented Cognition: An Examination Among Treatment-seeking Adults Who Smoke

OBJECTIVES

Elevated levels of anxiety sensitivity (AS; fear of anxiety and internal sensations) is highly common among adults who smoke, and contributes to several maladaptive smoking beliefs and behaviors. AS is comprised of 3 empirically established factors, relating to fears of social concerns, fears of physical symptoms, and fears of cognitive dyscontrol. Relatively few studies have examined how these 3 subscales pertain to smoking processes. The aim of the present investigation was to examine, among treatment-seeking adults who smoke, the interactive effects of AS-physical and cognitive concerns in relation to: perceived barriers to smoking cessation; smoking-related negative reinforcement expectancies; and smoking-related avoidance and inflexibility.

METHODS

Participants included 470 adults who smoke (47.8% female; mean age 37.2, SD 13.5), who were recruited to participate in a smoking-cessation treatment study. At the baseline assessment, participants completed self-report measures, including the Anxiety Sensitivity Index-3, Barriers to Cessation Scale, Smoking Consequences Questionnaire, and Avoidance and Inflexibility Scale.

RESULTS

Results indicated that after controlling for the effects of sex, cigarette dependence, alcohol problems, tobacco-related medical illness, current axis 1 disorder, and AS-social concerns, a significant interaction emerged, such that the association between AS-cognitive concerns and the studied smoking-based cognitions were stronger among lower levels of AS-physical concerns (but not higher physical concerns).

CONCLUSIONS

The current findings suggest that it may be beneficial to provide specialized smoking-cessation interventions for certain subgroups of adults who smoke, such as those with different AS profiles, to promote healthier beliefs about quitting.

The Role of Cognitive Control in the Self-Regulation and Reinforcement of Smoking Behavior

Cognitive control (CC)-the ability to regulate attention and memory-plays an important role in a variety of health behaviors, including smoking behavior. In this theoretical review of the literature, we propose a CC and smoking behavior framework that includes (1) the positive influence of CC on the self-regulation of smoking, (2) nicotine-induced improvements in CC that may indirectly reinforce smoking (including withdrawal reversal effects), and (3) the long-term effects of smoking on the brain that may result in reduced CC. Integration of these literatures suggests that CC contributes to both self-regulation (ie, brake pedal) and nicotine-related reinforcement (ie, gas pedal) amid the catastrophic effects of long-term smoking, which may reduce self-regulatory control over smoking while also enhancing indirect reinforcement. Supportive evidence and limitations of this approach will be presented, as well as ideas for future research directions that may fully examine this multifaceted modeling of CC in relation to smoking behavior.

IMPLICATIONS

There is substantial evidence that CC contributes to self-regulation (ie, brake pedal) and reinforcement (ie, gas pedal) of smoking behavior as well as evidence that long-term smoking may cause reduced CC. The proposed model delineates how these opposing influences of CC may mask the unique contribution of self-regulation and reinforcement in maintaining smoking behavior. Targeting CC for treating nicotine dependence will require more nuanced approaches that consider the independent and combined effects of self-regulation and reinforcement to improve smoking cessation success rates.

A case-control genome-wide association study of ADHD discovers a novel association with the tenascin R (TNR) gene

It is well-established that there is a strong genetic contribution to the aetiology of attention deficit hyperactivity disorder (ADHD). Here, we employed a hypothesis-free genome-wide association study (GWAS) design in a sample of 480 clinical childhood ADHD cases and 1208 controls to search for novel genetic risk loci for ADHD. DNA was genotyped using Illumina's Human Infinium PsychArray-24v1.2., and the data were subsequently imputed to the 1000 Genomes reference panel. Rigorous quality control and pruning of genotypes at both individual subject and single nucleotide polymorphism (SNP) levels was performed. Polygenic risk score (PGRS) analysis revealed that ADHD case-control status was explained by genetic risk for ADHD, but no other major psychiatric disorders. Logistic regression analysis was performed genome-wide to test the association between SNPs and ADHD case-control status. We observed a genome-wide significant association (p = 3.15E-08) between ADHD and rs6686722, mapped to the Tenascin R (TNR) gene. Members of this gene family are extracellular matrix glycoproteins that play a role in neural cell adhesion and neurite outgrowth. Suggestive evidence of associations with ADHD was observed for an additional 111 SNPs (⩽9.91E-05). Although intriguing, the association between DNA variation in the TNR gene and ADHD should be viewed as preliminary given the small sample size of this discovery dataset.

Associations between urinary cotinine and symptoms of attention deficit/hyperactivity disorder and autism spectrum disorder

BACKGROUND

The present study investigated associations between urinary cotinine levels as a biomarker of secondhand smoke exposure and symptoms of attention deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD).

METHODS

A total of 520 child participants (200 with ADHD, 67 with ASD, and 253 normal control subjects) were assessed using the Korean version of the ADHD rating scale (K-ARS), Autism spectrum screening questionnaire (ASSQ), and Behavioral Assessment System for Children, second edition (BASC-2). The Korean version of the computer-based continuous performance test was used to assess cognitive function. Urinary cotinine was evaluated as a biomarker of secondhand smoke exposure.

RESULTS

Urinary cotinine levels were significantly and positively associated with K-ARS score (B = 4.00, p < 0.001), ASSQ score (B = 1.71, p = 0.030), the behavioral problem subscales of the BASC-2 (B = 1.68-3.52, p < 0.001-0.045), and omission and commission errors in the continuous performance test (B = 6.21-8.42, p < 0.001-0.019). Urinary cotinine levels were also associated with the increased odds ratio of ADHD (OR = 1.55, 95% CI 1.05-2.30, p = 0.028) and ASD (OR = 1.89, 95% CI 1.12-3.21, p = 0.018).

CONCLUSION

Urinary cotinine levels were associated with lower behavioral adaptation and cognitive function and increased odds ratios of ADHD and ASD, indicating a negative effect of secondhand smoke exposure on the symptomatic manifestation of ADHD and ASD.

Investigating possible causal effects of externalizing behaviors on tobacco initiation: A Mendelian randomization analysis

Observational studies suggest childhood externalizing disorders are associated with increased smoking and earlier initiation. However, causality cannot be inferred from observational data alone. The current study uses two-sample MR to examine the causal relationship between externalizing behaviors and tobacco use. Single nucleotide polymorphisms (SNPs) associated with aggression were obtained from the Early Life Epidemiology Consortium (mean age 8), ADHD from the Integrative Psychiatric Research and Psychiatric Genomics Consortiums (age range 6-18), and tobacco initiation and age of onset from the Tobacco and Genetics Consortium. SNPs were combined using the inverse variance weighted approach, weighted median approach, and MR-Egger regression. There was no clear evidence of an effect of aggression on tobacco initiation or age of onset for childhood aggression (initiation: β -0.002, 95% CI -0.005, 0.001, P = 0.286; age: β -0.001 95% CI -0.002, 0.000, P = 0.310) or adolescent aggression (initiation: β -0.001, 95% CI -0.006, 0.003, P = 0.610; age: β 0.000, 95% CI 0.000, 0.001, P = 0.183)]. However, there was some evidence of an association of ADHD on tobacco initiation (OR 1.23, 95% CI 1.10, 1.35, P = 0.016), although no clear evidence of an effect of ADHD on age of onset (OR = 1.022, 95% CI 0.992, 1.052, P = 0.215). Our results provide some evidence that genetic risk of childhood ADHD is causally related to increased risk of tobacco initiation; however, the causal estimate is relatively small. We found no clear evidence that genetic risk of childhood aggression is causally related to the risk of tobacco initiation or age of onset.

Common psychiatric and metabolic comorbidity of adult attention-deficit/hyperactivity disorder: A population-based cross-sectional study

Attention-deficit/hyperactivity disorder (ADHD) is often comorbid with other psychiatric conditions in adults. Yet, less is known about its relationship with common metabolic disorders and how sex and ageing affect the overall comorbidity patterns of adult ADHD. We aimed to examine associations of adult ADHD with several common psychiatric and metabolic conditions. Through the linkage of multiple Swedish national registers, 5,551,807 adults aged 18 to 64 years and living in Sweden on December 31, 2013 were identified and assessed for clinical diagnoses of adult ADHD, substance use disorder (SUD), depression, bipolar disorder, anxiety, type 2 diabetes mellitus (T2DM), and hypertension. Logistic regression models and regression standardization method were employed to obtain estimates of prevalence, prevalence difference (PD), and prevalence ratio (PR). All comorbid conditions of interest were more prevalent in adults with ADHD (3.90% to 44.65%) than in those without (0.72% to 4.89%), with the estimated PRs being over nine for psychiatric conditions (p < 0.001) and around two for metabolic conditions (p < 0.001). Sex differences in the prevalence of comorbidities were observed among adults with ADHD. Effect modification by sex was detected on the additive scale and/or multiplicative scale for the associations of adult ADHD with all comorbidities. ADHD remained associated with all comorbidities in older adults aged 50 to 64 when all conditions were assessed from age 50 onwards. The comorbidity patterns of adult ADHD underscore the severity and clinical complexity of the disorder. Clinicians should remain vigilant for a wide range of psychiatric and metabolic problems in ADHD affected adults of all ages and both sexes.

Relationship between attention-deficit hyperactivity disorder symptoms and problem gambling: A mediation analysis of influential factors among 7,403 individuals from the UK

BACKGROUND AND AIMS

Our goal was to examine the association between attention-deficit hyperactivity disorder (ADHD) symptoms and gambling problems, and to identify potential mediating factors of this association.

METHODS

This study used cross-sectional, community-based data from 7,403 people aged ≥16 years who participated in the Adult Psychiatric Morbidity Survey 2007. ADHD symptoms were assessed using the Adult ADHD Self-Report Scale (ASRS) Screener. Problem gambling was assessed using a questionnaire based on the 10 DSM-IV diagnostic criteria for pathological gambling. Respondents were classified as having no problem, at-risk, or problem gambling. Logistic regression and mediation analyses were conducted to analyze the association between ADHD symptoms (i.e., ASRS score ≥14) and problem gambling and the role of several variables in this association.

RESULTS

The prevalence of at-risk (5.3% vs. 2.4%) and problem gambling (2.4% vs. 0.6%) was higher in individuals with ADHD symptoms than in those without ADHD symptoms. ADHD symptoms were significantly associated with both at-risk (OR = 2.15; 95% CI = 1.22-3.79) and problem gambling (OR = 3.57; 95% CI = 1.53-8.31) when adjusted for age, sex, and ethnicity. Common mental disorders (CMDs; i.e., depression and anxiety disorders) (mediated percentage = 22.4%), borderline personality disorder (BPD) traits (22.1%), stressful life events (13.2%), stress at work or home (12.6%), alcohol dependence (11.8%), and impulsivity (11.2%) were significant mediators in the ADHD-gambling association.

DISCUSSION AND CONCLUSIONS

Overall, ADHD symptoms were positively associated with problem gambling. CMDs, BPD traits, and stressful life events were important mediators in this relationship.

Association of Polygenic Risk for Attention-Deficit/Hyperactivity Disorder With Co-occurring Traits and Disorders

BACKGROUND

A recent large-scale mega genome-wide association study identified, for the first time, genetic variants at 12 loci significantly associated with attention-deficit/hyperactivity disorder (ADHD). In this study we use a powerful polygenic approach, with polygenic scores derived from the genome-wide association study, to investigate the etiological overlap between ADHD and frequently co-occurring traits and disorders.

METHODS

Polygenic risk scores for ADHD derived from the mega genome-wide association study (20,183 cases and 35,191 control subjects) were computed in a large-scale adult population sample (N = 135,726) recruited by the UK Biobank. Regression analyses were conducted to investigate whether polygenic risk for ADHD is associated with related traits and disorders in this population sample. The effects of sex were investigated via inclusion of an interaction term in the models.

RESULTS

Polygenic risk for ADHD significantly and positively predicted body mass index (R2 = .45%; p = 5 × 10-129), neuroticism (R2 = .09%; p = 2 × 10-24), depression (R2 = .11%; p = 2 × 10-13), anxiety (R2 = .06%; p = 3 × 10-4), risk taking (R2 = .12%; p = 9 × 10-25), alcohol intake (R2 = .09%; p = 8 × 10-29), smoking (R2 = .33%; p = 4 × 10-21), alcohol dependency (R2 = .21%; p = 5 × 10-6), and negatively predicted verbal-numerical reasoning (R2 = .38%; p = 5 × 10-36). Polygenic risk scores did not significantly predict schizophrenia or bipolar disorder, although this may be because of the small number of diagnostic cases. We found no interaction effects between polygenic risk for ADHD and sex on any phenotypes.

CONCLUSIONS

Our findings suggest that common genetic variation underlying risk for clinically diagnosed ADHD also contributes to higher body mass index, neuroticism, anxiety and depressive disorders, alcohol and nicotine use, risk taking, and lower general cognitive ability in the general population. These findings suggest that the co-occurrence of several traits with ADHD is partly explained by the same common genetic variants.

Analysis of shared heritability in common disorders of the brain

Disorders of the brain can exhibit considerable epidemiological comorbidity and often share symptoms, provoking debate about their etiologic overlap. We quantified the genetic sharing of 25 brain disorders from genome-wide association studies of 265,218 patients and 784,643 control participants and assessed their relationship to 17 phenotypes from 1,191,588 individuals. Psychiatric disorders share common variant risk, whereas neurological disorders appear more distinct from one another and from the psychiatric disorders. We also identified significant sharing between disorders and a number of brain phenotypes, including cognitive measures. Further, we conducted simulations to explore how statistical power, diagnostic misclassification, and phenotypic heterogeneity affect genetic correlations. These results highlight the importance of common genetic variation as a risk factor for brain disorders and the value of heritability-based methods in understanding their etiology.

Minor physical anomalies in adolescents at risk for substance use and early sex

Minor physical anomalies (MPAs) are associated with disruptions of fetal development. We propose that the same genetic compositions that contribute to the presence of MPAs, also predispose individuals to health-compromising behaviors, thus considering MPAs as particular endophenotypes.We developed a screening questionnaire for problematic conduct, substance abuse, and early sexual practice. A total of 108 adolescents (55 males, 50.9%) aged 11 to 19 years were recruited and further divided into case and control groups according to their answers to the questions of health behaviors mentioned above. We then measured their MPAs that included qualitative and quantitative physical features. Stepwise logistic regression and the receiver operating characteristic (ROC) analyses were used to determine the predictive values of MPAs for behavioral outcomes.The obliquity of palpebral fissure and the head MPAs were negatively associated with substance use. In the ROC analysis, the model provided an area under curve (AUC) of 0.91 with prediction indices being 0.89 for sensitivity and 0.85 for specificity. In addition, the feet MPAs and outer canthal distance were positively, whereas the obliquity of palpebral fissure and ear rotation was negatively associated with early sexual practices. The AUC for early sexual practice was 0.91 and the prediction indexes were 0.87 for sensitivity and 0.88 for specificity.Certain MPAs were associated with adolescent substance use and early sex, which suggests a neurodevelopmental etiology for behavioral outcomes.

Associations between attention-deficit/hyperactivity disorder and autoimmune diseases are modified by sex: a population-based cross-sectional study

Several studies have demonstrated associations between neuropsychiatric disorders, such as attention-deficit/hyperactivity disorder (ADHD), and the immune system, including autoimmune diseases. Since ADHD and many autoimmune diseases show sex-specific properties, such associations may also differ by sex. Using Norwegian national registries, we performed a cross-sectional study based on a cohort of 2,500,118 individuals to investigate whether ADHD is associated with common autoimmune diseases. Associations between ADHD and autoimmune diseases in females and males were investigated with logistic regression and effect modification by sex was evaluated. Several subanalyses were performed. The strongest association was found between ADHD and psoriasis in females, adjusted odds ratio (adjOR) = 1.57 (95% confidence interval: 1.46-1.68) and males, adjOR = 1.31 (1.23-1.40); p value for interaction < 0.0001. Furthermore, among females, ADHD was associated with Crohn's disease, adjOR = 1.44 (1.16-1.79) and ulcerative colitis, adjOR = 1.28 (1.06-1.54). In contrast, males with ADHD had lower odds of Crohn's disease, adjOR = 0.71 (0.54-0.92), in addition to a trend for lower odds of ulcerative colitis, adjOR = 0.86 (0.71-1.03); p values for interaction < 0.0001 and 0.0023, respectively. In a group of females where information on smoking and body mass index was available, adjustment for these potential mediators did not substantially alter the associations. Our findings support previously reported associations between ADHD and diseases of the immune system. The associations differ by sex, suggesting that sex-specific immune-mediated neurodevelopmental processes may be involved in the etiology of ADHD.

Smoking, ADHD, and Problematic Video Game Use: A Structural Modeling Approach

Problematic video game use (PVGU), or addiction-like use of video games, is associated with physical and mental health problems and problems in social and occupational functioning. Possible correlates of PVGU include frequency of play, cigarette smoking, and attention deficit hyperactivity disorder (ADHD). The aim of the current study was to explore simultaneously the relationships among these variables as well as test whether two separate measures of PVGU measure the same construct, using a structural modeling approach. Secondary data analysis was conducted on 2,801 video game users (M_age = 22.43 years, standard deviation [SD]_age = 4.7; 93 percent male) who completed an online survey. The full model fit the data well: χ² (2) = 2.017, p > 0.05; root mean square error of approximation (RMSEA) = 0.002 (90% CI [0.000-0.038]); comparative fit index (CFI) = 1.000; standardized root mean square residual (SRMR) = 0.004; and all standardized residuals <|0.1|. All freely estimated paths were statistically significant. ADHD symptomatology, smoking behavior, and hours of video game use explained 41.8 percent of variance in PVGU. Tracking these variables may be useful for PVGU prevention and assessment. Young's Internet Addiction Scale, adapted for video game use, and the Problem Videogame Playing Scale both loaded strongly onto a PVGU factor, suggesting that they measure the same construct, that studies using either measure may be compared to each other, and that both measures may be used as a screener of PVGU.

ADHD, Smoking Withdrawal, and Inhibitory Control: Results of a Neuroimaging Study with Methylphenidate Challenge

Smoking withdrawal negatively impacts inhibitory control, and these effects are greater for smokers with preexisting attention problems, such as attention deficit/hyperactivity disorder (ADHD). The current study preliminarily evaluated changes in inhibitory control-related behavior and brain activation during smoking withdrawal among smokers with ADHD. Moreover, we investigated the role of catecholamine transmission in these changes by examining the effects of 40 mg methylphenidate (MPH) administration. Adult daily smokers with (n=17) and without (n=20) ADHD completed fMRI scanning under each of three conditions: (a) smoking as usual+placebo; (b) 24 h smoking abstinence+placebo and (c) 24 h smoking abstinence+MPH. Scan order was randomized and counterbalanced. Participants completed a modified Go/No-Go task to assess both sustained and transient inhibitory control. Voxelwise analysis of task-related BOLD signal revealed a significant group-by-abstinence interaction in occipital/parietal cortex during sustained inhibition, with greater abstinence-induced decreases in activation observed among ADHD smokers compared with non-ADHD smokers. Changes in behavioral performance during abstinence were associated with changes in activation in regions of occipital and parietal cortex and bilateral insula during sustained inhibition in both groups. MPH administration improved behavioral performance and increased sustained inhibitory control-related activation for both groups. During transient inhibition, MPH increased prefrontal activation for both groups and increased striatal activation only among ADHD smokers. These preliminary findings suggest that abstinence-induced changes in catecholamine transmission in visual attention areas (eg, occipital and superior parietal cortex) may be associated with inhibitory control deficits and contribute to smoking vulnerability among individuals with ADHD.

Exploring longitudinal course and treatment-baseline severity interactions in secondary outcomes of smoking cessation treatment in individuals with attention-deficit hyperactivity disorder

BACKGROUND

A double blind, placebo-controlled randomized trial (NCT00253747) evaluating osmotic-release oral system methylphenidate (OROS-MPH) for smoking-cessation revealed a significant interaction effect in which participants with higher baseline ADHD severity had better abstinence outcomes with OROS-MPH while participants with lower baseline ADHD severity had worse outcomes.

OBJECTIVES

This current report examines secondary outcomes that might bear on the mechanism for this differential treatment effect.

METHODS

Longitudinal analyses were conducted to evaluate the effect of OROS-MPH on three secondary outcomes (ADHD symptom severity, nicotine craving, and withdrawal) in the total sample (N = 255, 56% Male), and in the high (N = 134) and low (N = 121) baseline ADHD severity groups.

RESULTS

OROS-MPH significantly improved ADHD symptoms and nicotine withdrawal symptoms in the total sample, and exploratory analyses showed that in both higher and lower baseline severity groups, OROS-MPH statistically significantly improved these two outcomes. No effect on craving overall was detected, though exploratory analyses showed statistically significantly decreased craving in the high ADHD severity participants on OROS-MPH. No treatment by ADHD baseline severity interaction was detected for the outcomes.

CONCLUSIONS

Methylphenidate improved secondary outcomes during smoking cessation independent of baseline ADHD severity, with no evident treatment-baseline severity interaction. Our results suggest divergent responses to smoking cessation treatment in the higher and lower severity groups cannot be explained by concordant divergence in craving, withdrawal and ADHD symptom severity, and alternative hypotheses may need to be identified.

Abstinence-induced withdrawal severity among adolescent smokers with and without ADHD: disentangling effects of nicotine and smoking reinstatement

RATIONALE

Individuals with attention deficit hyperactivity disorder (ADHD) start smoking earlier, are more likely to progress to nicotine dependence, and have a more difficult time quitting smoking compared to their non-ADHD peers. Little is known about the underlying behavioral mechanisms associated with this increased risk, particularly at the adolescent stage.

OBJECTIVE

This study aimed to assess the effects of overnight nicotine abstinence and smoking reinstatement on subjective withdrawal states in adolescent smokers with and without ADHD.

METHODS

Adolescent daily smokers (27 with ADHD and 17 without ADHD) completed three experimental sessions: (1) a placebo patch followed by smoking a nicotine cigarette, (2) placebo patch followed by smoking a nicotine-free cigarette, and (3) nicotine patch followed by smoking a nicotine-free cigarette. Subjects abstained overnight before each session, and patches were administered 45 min before smoking. The primary outcome measure was a smoking withdrawal symptom questionnaire.

RESULTS

ADHD smokers experienced greater difficulty concentrating and impatience/restlessness during abstinence than non-ADHD smokers. Smoking a cigarette improved abstinence-induced difficulty concentrating and restlessness, regardless of its nicotine content, and regardless of whether transdermal nicotine was received or not.

CONCLUSIONS

Thus, sensorimotor aspects of smoking, rather than nicotine itself, appeared to relieve withdrawal. Although ADHD smokers report greater withdrawal symptoms than non-ADHD smokers, they responded strongly to the sensorimotor aspects of smoking during withdrawal. These findings suggest that even lighter, adolescent smokers with ADHD are vulnerable to smoking progression through altered smoking abstinence and withdrawal relief processes.

ADHD symptoms impact smoking outcomes and withdrawal in response to Varenicline treatment for smoking cessation

INTRODUCTION

Attention-Deficit/Hyperactivity Disorder (ADHD) is associated with nicotine dependence and difficulty quitting smoking. Few cessation trials specifically consider the impact of ADHD on treatment outcomes, including those testing established pharmacological therapies, such as varenicline.

METHODS

The current study focused on the impact of pretreatment ADHD inattention (IN) and hyperactivity-impulsivity (HI) symptoms on treatment outcome in a randomized controlled trial of varenicline [N=205, average age=34.13(10.07), average baseline cigarettes per day=14.71(7.06)]. Given that varenicline's putative therapeutic mechanism is attenuation of withdrawal severity during abstinence, we also tested changes in withdrawal as a mediator of treatment effects in high and low ADHD groups.

RESULTS

ADHD symptom severity in this sample was in the subclinical range. Cessation was associated with HI, but not IN, such that high HI individuals on varenicline reported the lowest smoking levels at the end of treatment across all groups (3.06cig/day for high HI vs 4.02cig/day for low HI). Individuals with high HI who received placebo had the highest smoking at the end of treatment (7.69cigs/day for high HI vs 5.56cig/day for low HI). Patterns continued at follow-up. Varenicline significantly reduced withdrawal for those with high HI, but not low HI. However, path models did not support an indirect effect of medication on reducing smoking via withdrawal in either group, suggesting that unmeasured variables are involved in varenicline's effect on reducing smoking.

CONCLUSIONS

These data add to a gap in the smoking cessation literature regarding the impact of ADHD symptoms on the efficacy and mechanisms of frontline pharmacological treatments.

Stress, attention deficit hyperactivity disorder (ADHD) symptoms and tobacco smoking: The i-Share study

BACKGROUND

The contribution of mental health to the risk of smoking is increasingly acknowledged but still insufficiently studied during the key period of student life. In particular, the simultaneous action of stress and Attention Deficit Hyperactivity Disorder (ADHD) symptoms on the risk of smoking remains poorly understood.

AIMS

To assess the effects of stress and ADHD symptoms on tobacco smoking.

METHOD

Multivariate modeling was conducted on the French i-Share study (n=8110, median age 20.3 years, 74.8% females, 32.9% regular/occasional smokers) to evaluate the associations between stress, ADHD symptoms and tobacco smoking, adjusting for potential family/socio-demographic confounders.

RESULTS

Students with high levels of stress were more likely to smoke>10 cigarettes/day (adjusted odds ratio (aOR): 1.48, 95% CI: 1.12-1.96) than those with low levels of stress. Students with high levels of ADHD symptoms were more likely to smoke>10 cigarettes/day (aOR: 2.08, 95% CI: 1.58-2.75) than those with low levels of ADHD symptoms.

CONCLUSIONS

Stress and ADHD contribute independently to the risk of smoking. Interventions targeting each condition are likely to reduce the burden of tobacco use in students.

Association of Pediatric Allergic Rhinitis with the Ratings of Attention-Deficit/Hyperactivity Disorder

Background

Allergic rhinitis (AR) is currently the most prevalent allergic disease in children and adolescents.

Objective

Surveys conducted by population-based studies of East Asia revealed an increased prevalence of behavioral disorders in patients with AR. Thus, in this study, we explored the prevalence of attention-deficit/hyperactivity disorder (ADHD) in pediatric patients with AR.

Methods

A total of 333 children (6–12 years of age) with AR and a total of 322 age-matched controls were included in this study. An otorhinolaryngologist diagnosed all AR cases and evaluated the severity of the disease. Skin-prick test results for 18 major allergens, Paediatric Rhinoconjunctivitis Quality of Life Questionnaire (PRQLQ), Child Behavior Checklist (CBCL), and Swanson, Nolan, and Pelham version IV (SNAP-IV) scores were recorded.

Results

In total, 320 age-matched controls and 323 children with AR completed the study. With respect to the Total Nasal Symptom Score and the PRQLQ, the condition of the experimental group was more serious than that of the controls. The scores on the hyperactivity/impulsivity and inattention subscales, which evaluate ADHD symptoms, and those on the CBCL subscales were significantly higher in patients with AR than in the controls (all p values were <0.01). From the results of the Pearson correlation, we deduced that there were significant positive correlations between the AR-related data and each subscale of the CBCL and SNAP-IV in the AR group. Moreover, two basic characteristics (males and environmental exposure to tobacco smoke) present significant positive and age showed a significant negative correlations affect ADHD symptom in both the AR group and the control group. Also, in the “pure AR” group, hierarchical regression analyses were performed to determine the subtests of the PRQLQ, which are significant predictors of SNAP-IV and CBCL.

Conclusions

Apart from AR per se, the possible comorbidities of impulsivity and inattention are important when managing children with AR. It is essential to evaluate the symptoms of ADHD in children and adolescents with AR.