ADHD as a serious risk factor for early smoking and nicotine dependence in adulthood

Sex Differences in Substance Use, Prevalence, Pharmacological Therapy, and Mental Health in Adolescents with Attention-Deficit/Hyperactivity Disorder (ADHD)

Sex differences are poorly studied within the field of mental health, even though there is evidence of disparities (with respect to brain anatomy, activation patterns, and neurochemistry, etc.) that can significantly influence the etiology and course of mental disorders. The objective of this work was to review sex differences in adolescents (aged 13–18 years) diagnosed with ADHD (according to the DSM-IV, DSM-IV-TR and DSM-5 criteria) in terms of substance use disorder (SUD), prevalence, pharmacological therapy and mental health. We searched three academic databases (PubMed, Web of Science, and Scopus) and performed a narrative review of a total of 21 articles. The main conclusions of this research were (1) girls with ADHD are more at risk of substance use than boys, although there was no consensus on the prevalence of dual disorders; (2) girls are less frequently treated because of underdiagnosis and because they are more often inattentive and thereby show less disruptive behavior; (3) together with increased impairment in cognitive and executive functioning in girls, the aforementioned could be related to greater substance use and poorer functioning, especially in terms of more self-injurious behavior; and (4) early diagnosis and treatment of ADHD, especially in adolescent girls, is essential to prevent early substance use, the development of SUD, and suicidal behavior.

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.

Differential implications of persistent, remitted, and late-onset ADHD symptoms for substance abuse in women and men: A twin study from ages 11 to 24

BACKGROUND

Persistence and emergence of ADHD in adulthood are associated with substance problems. We investigate differential implications of ADHD course for tobacco, alcohol, or marijuana problems by sex, then whether substance misuse results from ADHD or contributes to it, through a twin differences design.

METHODS

A population-based cohort of 998 twins (61 % monozygotic; 52 % female), born in Minnesota from 1988 to 1994, was prospectively assessed from ages 11-24. Childhood ADHD was oversampled. At age 24, 255 had a history of childhood-onset ADHD (160 persistent, 95 remitted); 93 had late-onset ADHD symptoms identified in late-adolescence/adulthood. Persistent, remitted, and late-onset groups were compared to those without ADHD (N = 459) on childhood characteristics and age-24 substance problems.

RESULTS

Persistent and late-onset groups differed in childhood; twin concordances suggested greater genetic etiology for persistent ADHD. As adolescents, however, both groups were high in conduct problems; by adulthood, they were comparably high in substance problems. In particular, women whose ADHD persisted were 5 times more likely to develop tobacco use disorder than women without ADHD. Remitted ADHD was associated with less-increased risk, except for alcohol problems among women. Consistent with possible causality, monozygotic female twins with more age-17 ADHD symptoms than co-twins had more age-24 tobacco symptoms; a similar association was found for alcohol.

CONCLUSIONS

Presence or emergence of ADHD in early adulthood increases substance problems to a greater degree for women than men. While effects of substances on later ADHD were not statistically significant, detection was limited by the relative rarity of late-adolescent substance symptoms.

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.

Attention-Deficit/Hyperactivity Disorder and Nicotine Dependence in Adults

Introduction

The aim of this study is to assess clinical characteristics and smoking profiles of individuals diagnosed with attention-deficit/hyperactivity disorder (ADHD) and compare their nicotine dependence status with healthy controls for better understanding the mutual and complex relationship between ADHD and smoking.

Methods

We included the following participants in the study: 40 adults with the diagnosis of ADHD, 40 participants who visited the smoking cessation polyclinic without any psychiatric disorders, and 40 healthy controls. A sociodemographic data form, Wender Utah Rating Scale (WURS), Adult ADD/ADHD Diagnosis and Evaluation Inventory, and Fagerstrom Nicotine Dependence Test (FNDT) were administered to the participants.

Results

Mean age of the ADHD, nicotine dependence, and control groups was 28.68±7.22, 34.17±8.60, 33.70±7.45 years, respectively. Percentages of females and males were 27.5% and 72.5% in the ADHD group, 50% and 50% in the nicotine dependence group, 47.5% and 52.5% in the control group. The attention-deficit scores in the ADHD, nicotine dependence, and control groups were 21.18±5.05, 7.23±3.96, 4.75±2.65, respectively (p=0.001), whereas the hyperactivity scores were.73±5.84, 6.43±4.2, and 3.58±2.27, respectively (p=0.001). The related features scores were 56.53±12.96, 24.30±13.93, and 13.13±6.11, respectively (p=0.001), whereas the WURS scores were 61.88±12.69, 23.03±16.07, 11.90±8.15, respectively (p=0.001). FNDT scores in ADHD and nicotine dependence groups were 5.83±2.11 and 6.20±2.74, respectively (p=0.495).

Conclusion

Considering the argument of ADHD being an independent risk factor for nicotine dependence, we think the co-occurrence of the smoking addiction and ADHD symptoms in the context of dopamine dysregulation is important in the clinical setting. Treatment modalities and of preventive strategies should be considered while keeping this in mind.

Six months methylphenidate treatment improves emotion dysregulation in adolescents with attention deficit/hyperactivity disorder: a prospective study

PURPOSE

Individuals with attention deficit/hyperactivity disorder (ADHD) may suffer from emotional dysregulation (ED), although this symptom is not listed among the diagnostic criteria. Methylphenidate (MPH) is useful in reducing emotional symptoms in ADHD. The aim of the present study was to determine both psychosocial risk factors and presence of ED in adolescents with ADHD before and after MPH treatment.

PARTICIPANTS AND METHODS

Eighty-two patients aged 12-18 years with ADHD were included as participants. The Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children - Present and Lifetime, the Difficulties in Emotion Regulation Scale (DERS), sociodemographic form, and the Inventory of Statements About Self-Injury were administered. Results were compared before and after 6 months MPH treatment.

RESULTS

A significant improvement was detected on DERS for impulsivity (15.9±6.8 initial vs 14.2±6.5 final test, p<0.01) and total score (88.4±23.3 initial vs 82.4±2.7 final test, p<0.05) across all patients taking MPH regardless of subtype and sex. Despite treatment, a significant difference remained for impulsivity, strategies, and total score in patients with comorbid oppositional defiant disorder (ODD) compared with those without ODD, but no difference was detected for conduct disorder comorbidity. In patients who self-harm, scores for goals, impulsivity, strategies, clarity, and total score were higher before treatment: furthermore, impulsivity and total score remained high after treatment. In maltreated patients, goals, impulsivity, strategies, and total scores were significantly higher before treatment; however, their symptoms were ameliorated after treatment with MPH.

CONCLUSION

Individuals with severe ED may "self-medicate" by smoking and/or self-harming. MPH led to significant improvements in ED possibly owing, in part, to a decrease in impulsivity, so that individuals felt more able to supervise their emotions and engage in goal-directed behaviors. ED should be considered particularly in patients with additional psychosocial factors and ODD comorbidity, and included in the treatment plan.

The Convention on the Rights of Persons with Disabilities as a tobacco control tool in the mental health setting

BACKGROUND

Smoking rates remain high among people with mental health conditions, even though smoking contributes to negative mental health outcomes and is a leading cause of mortality. Many mental health facilities are not covered by smoke-free laws or do not encourage smoking cessation, and people with mental health conditions are often targeted in tobacco industry promotions.

OBJECTIVE

To analyse how the Convention on the Rights of Persons with Disabilities (CRPD), to which most countries are a Party, obliges State Parties to review policies and practices for tobacco control in the mental health setting.

METHOD

Analysis of CRPD Articles relevant to smoking and mental health.

RESULTS

The CRPD contains several provisions that oblige State Parties to address the issue of smoking and mental health, particularly in relation to quit services, smoke-free policies in mental health facilities, health education focused on correcting misperceptions about smoking and mental health, and protecting people with mental health conditions from tobacco industry targeting.

CONCLUSIONS

The CRPD is a potentially powerful tool to promote tobacco control in the mental health context.

Evidence of Altered Brain Responses to Nicotine in an Animal Model of Attention Deficit/Hyperactivity Disorder

Introduction

Individuals with attention deficit/hyperactivity disorder (ADHD) are susceptible to earlier and more severe nicotine addiction. To shed light on the relationship between nicotine and ADHD, we examined nicotine's effects on functional brain networks in an animal model of ADHD.

Methods

Awake magnetic resonance imaging was used to compare functional connectivity in adolescent (post-natal day 44 ± 2) males of the spontaneously hypertensive rat (SHR) strain and two control strains, Wistar-Kyoto and Sprague-Dawley (n = 16 each). We analyzed functional connectivity immediately before and after nicotine exposure (0.4 mg/kg base) in naïve animals, using a region-of-interest approach focussing on 16 regions previously implicated in reward and addiction.

Results

Relative to the control groups, the SHR strain demonstrated increased functional connectivity between the ventral tegmental area (VTA) and retrosplenial cortex in response to nicotine, suggesting an aberrant response to nicotine. In contrast, increased VTA-substantia nigra connectivity in response to a saline injection in the SHR was absent following a nicotine injection, suggesting that nicotine normalized function in this circuit.

Conclusions

In the SHR, nicotine triggered an atypical response in one VTA circuit while normalizing activity in another. The VTA has been widely implicated in drug reward. Our data suggest that increased susceptibility to nicotine addiction in individuals with ADHD may involve altered responses to nicotine involving VTA circuits.

Implications

Nicotine addiction is more common among individuals with ADHD. We found that two circuits involving the VTA responded differently to nicotine in animals that model ADHD in comparison to two control strains. In one circuit, nicotine normalized activity that was abnormal in the ADHD animals, while in the other circuit nicotine caused an atypical brain response in the ADHD animals. The VTA has been implicated in drug reward. Our results would be consistent with an interpretation that nicotine may normalize abnormal brain activity in ADHD, and that nicotine may be more rewarding for individuals with ADHD.

Retrospective assessment of childhood ADHD symptoms for diagnosis in adults: validity of a short 8-item version of the Wender-Utah Rating Scale

The Wender-Utah Rating Scale (WURS) is a widely used self-report instrument for retrospective assessment of childhood ADHD. However, many WURS items are not specific to ADHD. Here, we investigated the effect of excluding these items on the performance of the WURS in predicting adult ADHD based on previous diagnosis and current clinically significant symptoms. The study was conducted on a sample of adults (n = 1014; 48 % male) participating in a family-based investigation of ADHD. Participants completed the 61-item WURS questionnaire and the 66-item Conners Adult ADHD Rating Scale. Receiver operating characteristic (ROC) curves were used to compare the performance of the eight-item WURS (WURS-8) and the longer WURS-25 in predicting previous ADHD diagnosis and current clinically significant ADHD symptoms. WURS-8 and WURS-25 have approximately the same power to predict adult ADHD, based on either previous diagnosis or current symptoms (area under the ROC curves >0.8). WURS-8 performs at least as well as the longer WURS-25 in predicting adult ADHD. This 8-item questionnaire is thus a valid instrument and is especially useful for screening for ADHD in large epidemiological samples.

Nicotine-induced behavioral sensitization in an adult rat model of attention deficit/hyperactivity disorder (ADHD)

Attention deficit hyperactivity disorder (ADHD) is associated with increased risk of tobacco dependence. Nicotine, the main psychoactive component of tobacco, appears to be implicated in ADHD-related tobacco dependence. However, the behavioral responsiveness to nicotine of the prevalent animal model of ADHD, the spontaneously hypertensive rat (SHR), is currently underinvestigated. The present study examined the activational effects of acute and chronic nicotine on the behavior of adult male SHRs, relative to Wistar Kyoto (WKY) controls. Experiment 1 verified baseline strain differences in open-field locomotor activity. Experiment 2 tested for baseline strain differences in rotational behavior using a Rotorat apparatus. Adult SHR and WKY rats were then exposed to a 7-day regimen of 0.6mg/kg/d s.c. nicotine, or saline, prior to each assessment. A separate group of SHRs underwent similar training, but was pre-treated with mecamylamine, a cholinergic antagonist. Nicotine sensitization, context conditioning, and mecamylamine effects were then tested. Baseline strain differences were observed in open-field performance and in the number of full rotations in the Rotorat apparatus, but not in the number of 90° rotations or direction changes. In these latter measures, SHRs displayed weaker nicotine-induced rotational suppression than WKYs. Both strains expressed nicotine-induced sensitization of rotational activity, but evidence for strain differences in sensitization was ambiguous; context conditioning was not observed. Mecamylamine reversed the effects of nicotine on SHR performance. These findings are consistent with the hypothesis that a reduced aversion to nicotine (expressed in rats as robust locomotion) may facilitate smoking among adults with ADHD.

Adult ADHD Medications and Their Cardiovascular Implications

Attention-deficit/hyperactivity disorder (ADHD) is a chronic neurobiological disorder exhibited by difficulty maintaining attention, as well as hyperactivity and impulsive behavior. Central nervous system (CNS) stimulants are the first line of treatment for ADHD. With the increase in number of adults on CNS stimulants, the question that arises is how well do we understand the long-term cardiovascular effects of these drugs. There has been increasing concern that adults with ADHD are at greater risk for developing adverse cardiovascular events such as sudden death, myocardial infarction, and stroke as compared to pediatric population. Cardiovascular response attributed to ADHD medication has mainly been observed in heart rate and blood pressure elevations, while less is known about the etiology of rare cardiovascular events like acute myocardial infarction (AMI), arrhythmia, and cardiomyopathy and its long-term sequelae. We present a unique case of AMI in an adult taking Adderall (mixed amphetamine salts) and briefly discuss the literature relevant to the cardiovascular safety of CNS stimulants for adult ADHD.

Smoking During Adolescence as a Risk Factor for Attention Problems

BACKGROUND

Cigarette smoking and attention-deficit/hyperactivity disorder (ADHD) are highly comorbid. One explanation is that individuals with ADHD use cigarettes as "self-medication" to alleviate their attention problems. However, animal studies reported that exposure to nicotine during adolescence influences the developing brain and negatively affects attention. This is the first human study exploring the effects of smoking during adolescence on attention problems.

METHODS

Longitudinal data on smoking and attention problems were available for 1987 adult and 648 adolescent monozygotic twin pairs from the Netherlands Twin Register. Twin pairs were classified as concordant/discordant for smoking and compared on attention problems. Within adult discordant pairs, the difference in attention problems between the smoking and never-smoking twins was first assessed cross-sectionally. In longitudinal analyses, the increase in attention problems from adolescence, when neither twin smoked, to adulthood was compared within discordant pairs. In subgroups with longitudinal data from childhood and adolescence, changes in smoking concordance and subsequent changes in attention problems were explored.

RESULTS

Adult twins who ever smoked reported significantly more attention problems than their never-smoking co-twin. Longitudinal analyses showed a larger increase in attention problems from adolescence to adulthood in smoking twins than their never-smoking co-twin (p < .05). In childhood and adolescence, smoking twins had more attention problems than their never-smoking co-twin, whereas scores were similar before smoking was initiated or after both twins started smoking (not significant in all groups).

CONCLUSIONS

Results from this genetically informative study suggest smoking during adolescence leads to higher attention problem scores, lasting into adulthood.

Serotonin/dopamine interactions in a hyperactive mouse: reduced serotonin receptor 1B activity reverses effects of dopamine transporter knockout

Knockout (KO) mice that lack the dopamine transporter (SL6A3; DAT) display increased locomotion that can be attenuated, under some circumstances, by administration of drugs that normally produce psychostimulant-like effects, such as amphetamine and methylphenidate. These results have led to suggestions that DAT KO mice may model features of attention deficit hyperactivity disorder (ADHD) and that these drugs may act upon serotonin (5-HT) systems to produce these unusual locomotor decreasing effects. Evidence from patterns of brain expression and initial pharmacologic studies led us to use genetic and pharmacologic approaches to examine the influence of altered 5-HT_1B receptor activity on hyperactivity in DAT KO mice. Heterozygous 5-HT_1B KO and pharmacologic 5-HT_1B antagonism both attenuated locomotor hyperactivity in DAT KO mice. Furthermore, DAT KO mice with reduced, but not eliminated, 5-HT_1B receptor expression regained cocaine-stimulated locomotion, which was absent in DAT KO mice with normal levels of 5-HT_1B receptor expression. Further experiments demonstrated that the degree of habituation to the testing apparatus determined whether cocaine had no effect on locomotion in DAT KO or reduced locomotion, helping to resolve differences among prior reports. These findings of complementation of the locomotor effects of DAT KO by reducing 5-HT_1B receptor activity underscore roles for interactions between specific 5-HT receptors and dopamine (DA) systems in basal and cocaine-stimulated locomotion and support evaluation of 5-HT_1B antagonists as potential, non-stimulant ADHD therapeutics.

Smoking behavior characteristics of non-selected smokers with childhood attention-deficit/hyperactivity disorder (AD/HD) history: a systematic review and meta-analysis

It is unclear whether adult smokers with childhood attention-deficit/hyperactivity disorder history (CH) have more severe smoking behavior than non-CH smokers, while it is clearly suggested that CH adolescents have more severe smoking behavior than CH adolescents. The aim of the present comprehensive meta-analysis is to determine whether CH smokers have more severe smoking behavior characteristics than those without and the effect of age on the association between CH and smoking behavior. We included all case-control studies and first round data collection of observational studies addressing the difference in smoking behavior characteristics of CH smokers versus non-CH smokers, with validated scales or structured interviews, without any language or date restriction. Nine studies (including 365 smokers with CH and 1,708 smokers without) were included. Compared to non-CH smokers, CH smokers smoked significantly more cigarettes [standardized mean differences (SMD) = 0.15, 95 % CI 0.01-0.28, p = 0.04] and began to regularly smoke earlier (SMD = -0.28, 95 % CI -0.49; -0.07, p = 0.01) but were not significantly more nicotine dependent (SMD = 0.23, 95 % CI -0.04 to 0.48, p = 0.08). After removing the single adolescent study, the significant association between CH and number of daily smoked cigarettes disappeared, and subgroups analyses confirmed that the significant association between CH and number of daily smoked cigarettes disappeared as age increased. Our meta-analysis illustrates a clinically important link between CH and tobacco smoking in adolescence but not later in life. Further high-quality studies are needed to confirm this finding, as only two studies included participants with a mean age below 20 years.

Meta-analysis of increased heart rate and blood pressure associated with CNS stimulant treatment of ADHD in adults

Compared to children, adults with ADHD are at greater risk for developing adverse cardiovascular related outcomes and, if treated, may be likely to carry a greater burden of exposure to stimulant medications. The goal of this report is to critically review the available literature relevant to the cardiovascular safety of CNS stimulants for adult ADHD (aADHD). Twenty potential clinical trials of a CNS stimulant for aADHD have been published between 1979 and 2012. Of these, ten presented sufficient data to estimate the relative change in various cardiovascular parameters associated with ADHD treatment modalities. These trials were predominantly focused on long-acting stimulant preparations for acute symptom reduction (median duration=6 weeks, range: 4-24 weeks) and enrolled relatively young subjects (median age=36 years, range: 22-40). Using random effects meta-analysis, we found that subjects randomized to CNS stimulant treatment demonstrated a statistically significant increased resting heart rate [+5.7bpm (3.6, 7.8), p<0.001] and systolic blood pressure findings [+2.0mmHg (0.8, 3.2), p=0.005] compared with subjects randomized to placebo. There was a statistically significant increased risk for a resting heart rate >90bpm [4.2% (n=50) vs. 1.7% (n=8), OR=2.75 (1.3, 6.7), p=0.006] associated with CNS stimulant treatment. In light of prognostic value of resting heart rate with regard to cardiovascular morbidity in epidemiological studies, future research of adults with ADHD should focus on the potential clinical impact of the increase in heart rate observed in this meta-analysis.