Adult attention deficit hyperactivity disorder is associated with asthma

The influence of asthma on neuroinflammation and neurodevelopment: From epidemiology to basic models

Asthma is a highly heterogeneous inflammatory disease that can have a significant effect on both the respiratory system and central nervous system. Population based studies and animal models have found asthma to be comorbid with a number of neurological conditions, including depression, anxiety, and neurodevelopmental disorders. In addition, maternal asthma during pregnancy has been associated with neurodevelopmental disorders in the offspring, such as autism spectrum disorders and attention deficit hyperactivity disorder. In this article, we review the most current epidemiological studies of asthma that identify links to neurological conditions, both as it relates to individuals that suffer from asthma and the impacts asthma during pregnancy may have on offspring neurodevelopment. We also discuss the relevant animal models investigating these links, address the gaps in knowledge, and explore the potential future directions in this field.

The Activity of Adenosine Deaminase and Dipeptidyl Peptidase IV in Children With Attention Deficit Hyperactivity Disorder

OBJECTIVE

In this study, to investigate the place of T cell-mediated immunity in the etiology of ADHD, for which we do not have enough information; we aimed to investigate the activity of DPP IV and ADA, which are T cell-related enzymes, and the relationship of these enzymes with ADHD symptoms in children with ADHD.

METHODS

Twenty-seven children aged 6 to 12 years with a diagnosis of attention deficit hyperactivity disorder and 27 children aged 6 to 12 years without any psychiatric disease were included in the study.

RESULTS

While serum ADA and DPP-IV activity were found to be statistically significantly higher in the group with ADHD. There was no statistically significant correlation between serum ADA and DPP-IV activities and CTRS-R-L and CPRS-R-L in both groups.

CONCLUSION

We think that T cell mediated inflammation may play a role in the etiology of ADHD due to changes in ADA and DPP-IV levels in children.

Characterizing the neuroimmune environment of offspring in a novel model of maternal allergic asthma and particulate matter exposure

Inflammation during pregnancy is associated with an increased risk for neurodevelopmental disorders (NDD). Increased gestational inflammation can be a result of an immune condition/disease, exposure to infection, and/or environmental factors. Epidemiology studies suggest that cases of NDD are on the rise. Similarly, rates of asthma are increasing, and the presence of maternal asthma during pregnancy increases the likelihood of a child being later diagnosed with NDD such as autism spectrum disorders (ASD). Particulate matter (PM), via air pollution, is an environmental factor known to worsen the symptoms of asthma, but also, PM has been associated with increased risk of neuropsychiatric disorders. Despite the links between asthma and PM with neuropsychiatric disorders, there is a lack of laboratory models investigating combined prenatal exposure to asthma and PM on offspring neurodevelopment. Thus, we developed a novel mouse model that combines exposure to maternal allergic asthma (MAA) and ultrafine iron-soot (UIS), a common component of PM. In the current study, female BALB/c mice were sensitized for allergic asthma with ovalbumin (OVA) prior to pregnancy. Following mating and beginning on gestational day 2 (GD2), dams were exposed to either aerosolized OVA to induce allergic asthma or phosphate buffered saline (PBS) for 1 h. Following the 1-h exposure, pregnant females were then exposed to UIS with a size distribution of 55 to 169 nm at an average concentration of 176 ± 45 μg/m3) (SD), or clean air for 4 h, over 8 exposure sessions. Offspring brains were collected at postnatal days (P)15 and (P)35. Cortices and hippocampal regions were then isolated and assessed for changes in cytokines using a Luminex bead-based multiplex assay. Analyses identified changes in many cytokines across treatment groups at both timepoints in the cortex, including interleukin-1 beta (IL-1β), and IL-17, which remained elevated from P15 to P35 in all treatment conditions compared to controls. There was a suppressive effect of the combined MAA plus UIS on the anti-inflammatory cytokine IL-10. Potentially shifting the cytokine balance towards more neuroinflammation. In the hippocampus at P15, elevations in cytokines were also identified across the treatment groups, namely IL-7. The combination of MAA and UIS exposure (MAA-UIS) during pregnancy resulted in an increase in microglia density in the hippocampus of offspring, as identified by IBA-1 staining. Together, these data indicate that exposure to MAA, UIS, and MAA-UIS result in changes in the neuroimmune environment of offspring that persist into adulthood.

Case report: ADHD and prognosis in tyrosinemia type 1

Neurometabolic disorders such as tyrosinemia type 1 (TYRSN1) may interfere with brain metabolism and show symptoms of attention-deficit hyperactivity disorder (ADHD) in patients treated with the enzyme inhibitor nitisinone [2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione, NTBC]. It has been reported that ADHD treatment improves treatment compliance, which is imperative for the long-term prognosis of patients with TYRSN1. In this study, we report the case of a male patient who was diagnosed with TYRSN1 at 3 months of age and was subsequently treated with NTBC, restricted protein intake, and amino acids supplementation. At 7 years of age, he was referred for neuropsychiatric assessment, diagnosed with ADHD, and treated with methylphenidate. The effects of the treatment were monitored via parental interviews, questionnaires covering ADHD symptoms, and a continuous performance test. A reduction in ADHD symptoms, particularly inattentiveness, was observed across all measures. The early identification of ADHD and the treatment of neurometabolic disorders, such as TYRSN1, may be important from a lifetime perspective as this may improve the prognosis of the medical condition as well.

Characterizing the Neuroimmune Environment of Offspring in a Novel Model of Maternal Allergic Asthma and Particulate Matter Exposure

Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by the presence of decreased social interactions and an increase in stereotyped and repetitive behaviors. Epidemiology studies suggest that cases of ASD are on the rise. Similarly, rates of asthma are increasing, and the presence of maternal asthma during pregnancy increases the likelihood of a child being later diagnosed with ASD. Particulate matter (PM), via air pollution, is an environmental factor known to worsen the symptoms of asthma, but also, PM has been associated with increased risk of neuropsychiatric disorders including ASD. Despite the links between asthma and PM with neuropsychiatric disorders, there is a lack of laboratory models investigating combined prenatal exposure to asthma and PM on offspring neurodevelopment. Thus, we developed a novel mouse model that combines exposure to maternal allergic asthma (MAA) and ultrafine iron-soot (UIS), a common component of PM. In the current study, female BALB/c mice were primed for allergic asthma with ovalbumin (OVA) prior to pregnancy. Following mating and beginning on gestational day 2 (GD2), dams were exposed to either aerosolized OVA or phosphate buffered saline (PBS) for 1 hour. Following the 1-hour exposure, pregnant females were then exposed to UIS or clean air for 4 hours. Offspring brains were collected at postnatal days (P)15 and (P)35. Cortices and hippocampal regions were then isolated and assessed for changes in cytokines using a Luminex bead-based multiplex assay. Analyses identified changes in many cytokines across treatment groups at both timepoints in the cortex, including interleukin-1 beta (IL-1β), IL-2, IL-13, and IL-17, which remained elevated from P15 to P35 in all treatment conditions compared to controls. In the hippocampus at P15, elevations in cytokines were also identified across the treatment groups, namely interferon gamma (IFNγ) and IL-7. The combination of MAA and UIS exposure (MAA-UIS) during pregnancy resulted in an increase in microglia density in the hippocampus of offspring, as identified by IBA-1 staining. Together, these data indicate that exposure to MAA, UIS, and MAA-UIS result in changes in the neuroimmune environment of offspring that persist into adulthood.

Associations between attention-deficit/hyperactivity disorder and allergic diseases: a two-sample Mendelian randomization study

Background

In some observational studies, attention-deficit/hyperactivity disorder has been linked to allergic diseases, but the findings are debatable. This study aimed to determine whether attention-deficit/hyperactivity disorder (ADHD) is causally related to allergic asthma, allergic rhinitis, pollen allergy, allergic urticaria, and allergic conjunctivitis using the two-sample Mendelian Randomization (MR) approach.

Methods

We did a two-sample Mendelian randomization (MR) study, which chose single nucleotide polymorphisms (SNPs) that are highly associated with attention-deficit/hyperactivity disorder (ADHD) levels from the Psychiatric Genomics Consortium (PGC) on 20,183 cases and 35,191 controls as our instruments. Outcomes datasets included genome-wide association study (GWAS) meta-analysis (n = 1,415,804). The summary statistics of outcome data were obtained from the FinnGen datasets including allergic asthma (10,877 cases and 180,942 controls), allergic rhinitis (8,430 cases and 298,829 controls), pollen allergy (4555cases and 301,734 controls), allergic urticaria (1792 cases and 299,491 controls) and allergic conjunctivitis (15,567 cases and 293,587 controls). Inverse variance weighted, MR-Egger, weighted median, were used to estimate the causal association between ADHD and allergic diseases. Cochran's Q test was used to quantify the heterogeneity of instrumental variables. MR-Egger intercept test, leave-one-out analysis, and the funnel plot were all used in sensitivity analyses.

Results

The Mendelian randomization (MR) analysis indicated that ADHD in inverse variance weighted [odds ratio (OR) = 1.0612; 95% confidence interval (CI):1.0192-1.1049; p = 0.0039] lightly increased the risk of allergic asthma. In MR sensitivity analyses of the weighted median, a similar association was found. But no evidence for an effect of ADHD on allergic asthma risk was found in additional methods: MR-Egger (OR = 0.9592, 95% CI: 0.8384-1.0974, p = 0.5457), and weighted median (OR: =1.0341, 95% CI: 0.9785-1.0929, p = 0.2330). Also, no strong evidence for an effect of ADHD on other allergic diseases (allergic rhinitis, pollen allergy, allergic urticaria, and allergic conjunctivitis) incidence was found using the inverse variance weighted (IVW) method, weighted median method, and MR-Egger regression.

Conclusion

Although several studies have found a link between ADHD and allergic diseases, our findings do not support that ADHD could increase allergic diseases incidence. Randomized controlled trials or Mendelian randomization studies with larger samples are still needed to draw more precise conclusions.

Maternal Allergic Asthma Induces Prenatal Neuroinflammation

Autism spectrum disorder (ASD) is a class of neurodevelopmental disorders characterized by impaired social interactions and communication skills and repetitive or stereotyped behaviors. Rates of ASD diagnosis continue to rise, with current estimates at 1 in 44 children in the US (Maenner 2021). Epidemiological studies have suggested a link between maternal allergic asthma and an increased likelihood of having a child diagnosed with ASD. However, a lack of robust laboratory models prevents mechanistic research from being carried out. We developed a novel mouse model of maternal asthma-allergy (MAA) and previously reported that offspring from these mothers exhibit behavioral deficits compared to controls. In addition, it was shown that epigenetic regulation of gene expression in microglia was altered in these offspring, including several autism candidate genes. To further elucidate if there is neuroinflammation in the fetus following MAA, we investigated how allergic asthma impacts the maternal environment and inflammatory markers in the placenta and fetal brain during gestation. Female C57Bl/6 mice were primed with ovalbumin (OVA) prior to allergic asthma induction during pregnancy by administering aerosolized ovalbumin or PBS control to pregnant dams at gestational days (GD)9.5, 12.5, and 17.5. Four hours after the final induction, placenta and fetal brains were collected and measured for changes in cytokines using a Luminex bead-based multiplex assay. Placental MAA tissue showed a decrease in interleukin (IL)-17 in male and female offspring. There was a sex-dependent decrease in female monocyte chemoattractant protein 1 (MCP-1). In male placentas, IL-4, C-X-C motif chemokine 10 (CXCL10)-also known as interferon γ-induced protein 10 kDa (IP-10)-and chemokine (C-C motif) ligand 5 (RANTES) were decreased. In fetal brains, elevated inflammatory cytokines were found in MAA offspring when compared to controls. Specifically, interferon-gamma (IFN-γ), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin 1α (IL-1α), IL-6, and tumor necrosis factor α (TNFα) were elevated in both males and females. In contrast, a decrease in the cytokine IL-9 was also observed. There were slight sex differences after OVA exposures. Male fetal brains showed elevated levels of macrophage inflammatory protein-2 (MIP-2), whereas female brains showed increased keratinocytes-derived chemokine (KC). In addition, IL-1𝛽 and IP-10 in male fetal brains were decreased. Together, these data indicate that repeated exposure to allergic asthma during pregnancy alters cytokine expression in the fetal environment in a sex-dependent way, resulting in homeostatic and neuroinflammatory alterations in the fetal brain.

Association between Polygenic Risk Scores for ADHD and Asthma: A Birth Cohort Investigation

OBJECTIVE

Shared genetic mechanisms have been hypothesized to explain the comorbidity between ADHD and asthma. To evaluate their genetic overlap, we relied on data from the 1982 Pelotas birth cohort to test the association between polygenic risk scores (PRSs) for ADHD (ADHD-PRSs) and asthma, and PRSs for asthma (asthma-PRSs) and ADHD.

METHOD

We analyzed data collected at birth, 2, 22, and 30 years from 3,574 individuals.

RESULTS

Subjects with ADHD had increased risk of having asthma (OR 1.92, 95% CI 1.01-3.66). The association was stronger for females. Our results showed no evidence of association between ADHD-PRSs and asthma or asthma-PRSs and ADHD. However, an exploratory analysis suggested that adult ADHD might be genetically associated with asthma.

CONCLUSION

Our results do not support a shared genetic background between both conditions. Findings should be viewed in light of important limitations, particularly the sample size and the self-reported asthma diagnosis. Studies in larger datasets are required to better explore the genetic overlap between adult ADHD and asthma.

Role of Sex Hormones at Different Physiobiological Conditions and Therapeutic Potential in MBD2 Mediated Severe Asthma

Sex hormone has become a “hot topic” to evaluate the hormonal therapeutic potential in severe asthma. Th17 cell is one of the main influencing factors involved in the pathogenesis of severe asthma, hence also called as kernel of severe asthma, and Th17 subtype of non-T2 asthma is less responsive (resistance) to inhaled corticosteroid (ICS), so severe in nature. Methyl-CpG binding domain protein 2 (MBD2) is overexpressed and regulates the Th17 differentiation, showing the possibility of therapeutic target in treating Th17 mediated severe asthma. Sex hormone fluctuates at the different physiobiological conditions of the human body and affects the asthma pathobiology showing its role in asthma prevalence, severity, remission, and therapy. This review briefly overviews the sex hormones, their influence in asthma at the different physiobiological conditions of human body, and MBD2 severe asthma connection with the possible therapeutic potential of sex steroids in MBD2 mediated Th17 predominant severe asthma. Male sex hormone tends to show a beneficial effect and possibly downregulates the expression of Th17 cells via regulating MBD2 through a mechanism distinct from corticosteroid treatment and guides us towards discovery of new therapeutic agent, reduces the asthma-related complications, and promotes long-term survival by lowering the risk of therapy-resistant issues of old age severe asthma.

Large-scale genetic investigation reveals genetic liability to multiple complex traits influencing a higher risk of ADHD

Attention Deficit-Hyperactivity Disorder (ADHD) is a complex psychiatric and neurodevelopmental disorder that develops during childhood and spans into adulthood. ADHD’s aetiology is complex, and evidence about its cause and risk factors is limited. We leveraged genetic data from genome-wide association studies (GWAS) and performed latent causal variable analyses using a hypothesis-free approach to infer causal associations between 1387 complex traits and ADHD. We identified 37 inferred potential causal associations with ADHD risk. Our results reveal that genetic variants associated with iron deficiency anemia (ICD10), obesity, type 2 diabetes, synovitis and tenosynovitis (ICD10), polyarthritis (ICD10), neck or shoulder pain, and substance use in adults display partial genetic causality on ADHD risk in children. Genetic variants associated with ADHD have a partial genetic causality increasing the risk for chronic obstructive pulmonary disease and carpal tunnel syndrome. Protective factors for ADHD risk included genetic variants associated with the likelihood of participating in socially supportive and interactive activities. Our results show that genetic liability to multiple complex traits influences a higher risk for ADHD, highlighting the potential role of cardiometabolic phenotypes and physical pain in ADHD’s aetiology. These findings have the potential to inform future clinical studies and development of interventions.

Attention-deficit/hyperactivity disorder has a state-dependent association with asthma: The role of systemic inflammation in a population-based birth cohort followed from childhood to adulthood

There is a high comorbidity between attention-deficit/hyperactivity disorder (ADHD) and asthma, and inflammation has been proposed as a potential pathophysiological mechanism behind this association. Most studies conducted so far have used a cross-sectional design, and none has evaluated the prevalence of asthma symptoms in patients with ADHD followed from childhood to adulthood. We relied on data from the 1993 Pelotas birth cohort to evaluate the association between ADHD and asthma in patients with distinct patterns of incidence, persistence and remission, and to explore the potential role of inflammatory markers in the comorbidity. We analyzed data from 3281 individuals from the 1993 Pelotas birth cohort collected at birth (1993), 11 years (2004), 18 years (2011), and 22 years (2015). Subjects were first classified according to their ADHD and asthma status as early-onset (EO) persistent (positive screening for ADHD at 11 years and diagnosis of ADHD according to DSM-5, except criterion E, at either 18 or 22 years), EO-remittent (positive screening for ADHD at 11 years only), late-onset (diagnosis of ADHD according to DSM-5, except criterion E, at 18 or 22 years only), or healthy subjects (negative for both conditions in all evaluation). After controlling for confounders, significant associations were observed between EO-remittent ADHD and EO-remittent asthma (OR 1.68, 95% CI 1.11-2.55), EO-persistent ADHD and EO-persistent asthma (OR 4.33, 95% CI 1.65-11.34), and between late-onset ADHD and late-onset asthma (OR 1.86, 95% CI 1.28-2.70), suggesting a state-dependent association. Serum interleukin-6 (IL-6) and C-reactive protein (CRP) were measured at the 18- and 22-year evaluations and compared between subjects positive for ADHD, asthma, and subjects with both or none conditions, regardless of the previously defined trajectories. Subjects with comorbid ADHD and asthma presented higher levels of IL-6 at the 18- and 22-year evaluations when compared to subjects negative for both conditions. Our results demonstrate a state-dependent association between ADHD and asthma despite underlying trajectories. Higher levels of serum IL-6 in patients with both conditions suggest that a pro-inflammatory environment might have a role in the pathophysiological mechanisms underlying the comorbidity.

Comparative analysis of clinical, physiological, temperamental and personality characteristics of elderly subjects and young subjects with asthma

BACKGROUND

Asthma is a heterogeneous disease of a complex etiology in which genetic, environmental and personality variables are important factors determining the development of complicated strategies related to coping with stress and temperament traits. Our thesis is that coping styles in asthmatic patients are modified by the environment (chronic inflammation and stress) which affects individual temperament traits in the course of time. Thus, patient age is one of factors which determine the clinical image of asthma and its natural history.

AIM

The aim of the study was to evaluate the variables describing stress coping styles and temperament in young (18 to 35 years old) and elderly asthmatics (aged ≥60 years).

MATERIAL AND METHODS

A total of 200 patients, 104 elderly and 96 young asthmatics were enrolled in the study. Apart from medical examination, the following tests were performed in all subjects: the Formal Characteristics of Behavior- Temperament Inventory (FCB-TI), Coping Inventory for Stressful Situations (CISS), Beck Depression Inventory, State-Trait Anxiety Inventory, and Borg Rating of Perceived Exertion (RPE) Scale.

RESULTS

Elderly patients with asthma exhibited higher intensity of anxiety as a trait, a higher level of depression and experienced dyspnea, as well as higher levels of stress coping strategies such as Avoidance-Oriented Coping (AOC), Distraction Seeking (DS) and Social Diversion (SD) compared to young asthmatics. In elderly patients, Perseverance and Sensory Sensitivity traits have been observed to decline with the duration and development of asthma at later life stages as opposed to young asthmatics, in whom these temperament characteristics are elevated.

CONCLUSIONS

Asthma is a heterogeneous disease of a complex etiopathogenesis that has a complex interplay with mental health. The present study confirms a relationship between age and stress coping strategies as well as temperament traits.

[Adult attention deficit hyperactivity disorder and comorbidity: new findings on epidemiological and genetic factors]

All large population-based administrative studies currently indicate a significant comorbidity of adult attention deficit hyperactivity disorder (ADHD) with addictive, anxiety and in particular affective disorders. In these investigations the risk for one of these comorbid disorders increased with increasing age of the ADHD patients. The most recent genome-wide association and correlation studies also revealed indications for joint genetic risk factors of ADHD with, in particular unipolar depression, bipolar disorder, autism spectrum disorders, Tourette's syndrome and to a lesser extent schizophrenia. The only psychiatric disorder that was negatively correlated with ADHD was anorexia nervosa. Additionally, cannabis and cocaine use were significantly positively genetically correlated with ADHD. Furthermore, an increased occurrence of some specific somatic diseases could be found in patients with adult ADHD. In particular, obesity, migraine, sleep disorders, asthma and celiac disease showed a significantly positive association with ADHD in several studies. No association was found between ADHD and cardiovascular disease. Here as well there are initial indications of joint genetic risk variants; however, data are still sparse and additional studies are needed before valid conclusions can be drawn. To some extent these associated somatic diseases might be differential diagnoses rather than true comorbidities, for example, obstructive sleep apnea syndrome (OSAS) can lead to ADHD-like symptoms that disappear when the OSAS is sufficiently treated. Therefore, it is important to keep the co-occurrence of psychiatric and somatic disorders in mind during the diagnostics and treatment of adult ADHD patients to improve their general health and quality of life.

Attention-deficit/hyperactivity disorder and physical multimorbidity: A population-based study

Background:

There has been little research on the association of attention-deficit/hyperactivity disorder (ADHD) with co-occurring physical diseases. The aim of this study was to examine the association between possible ADHD and physical multimorbidity (i.e. = 2 physical diseases) among adults in the English general population.

Methods:

Data were analyzed from 7274 individuals aged = 18 years that came from the Adult Psychiatric Morbidity Survey 2007. ADHD symptoms were assessed with the Adult Self-Report Scale (ASRS) Screener. Information was also obtained on 20 self-reported doctor/other health professional diagnosed physical health conditions present in the past 12 months. Multivariable logistic regression and mediation analyses were conducted to assess the associations.

Results:

There was a monotonic relation between the number of physical diseases and possible ADHD (ASRS score = 14). Compared to those with no diseases, individuals with = 5 diseases had over 3 times higher odds for possible ADHD (odds ratio [OR]: 3.30, 95% confidence interval [CI]: 2.48–4.37). This association was observed in all age groups. Stressful life events (% mediated 10.3–24.3%), disordered eating (6.8%), depression (12.8%), and anxiety (24.8%) were significant mediators in the association between possible ADHD and physical multimorbidity.

Conclusion:

Adults that screen positive for ADHD are at an increased risk for multimorbidity and several factors are important in this association. As many adults with ADHD remain undiagnosed, the results of this study highlight the importance of detecting adult ADHD as it may confer an increased risk for poorer health outcomes, including physical multimorbidity.

Health-Related Quality of Life and Work Productivity of Adults With ADHD: A U.K. Web-Based Cross-Sectional Survey

OBJECTIVE

The objective of this study was to assess health-related quality of life (HRQoL) in adult ADHD.

METHOD

U.K. residents aged 18 to 55 years with ADHD and no major mental health comorbidities completed an online survey of disorder history, the EuroQoL 5-Dimensions 5-Level (EQ-5D-5L), and the Work Productivity and Activity Impairment Questionnaire: General Health (WPAI:GH). ADHD Rating Scale-IV (ADHD-RS-IV) score was assessed by telephone.

RESULTS

In total, 233 participants completed the study (mean age 32.6 years; 65.2% women). Mean ( SD) ADHD-RS-IV total score, EQ-5D utility, and visual analog scale (VAS) scores were 43.5 (7.88), 0.74 (.21), and 69.8 (17.76), respectively. Mean ( SD) WPAI:GH scores indicated that health problems caused 45.7% (29.9) overall work impairment and 45.8% (28.9) impairment in regular daily activities. Greater work and activity impairment were both significantly independently associated with lower utility after adjusting for age, gender, and somatic comorbidities.

CONCLUSION

Adult ADHD impairs HRQoL, work productivity, and regular daily activities.

Integrated Analysis of microRNA and mRNA Expression Profiles: An Attempt to Disentangle the Complex Interaction Network in Attention Deficit Hyperactivity Disorder

Attention Deficit Hyperactivity Disorder (ADHD) is a childhood-onset neurodevelopmental disorder, whose etiology and pathogenesis are still largely unknown. In order to uncover novel regulatory networks and molecular pathways possibly related to ADHD, we performed an integrated miRNA and mRNA expression profiling analysis in peripheral blood samples of children with ADHD and age-matched typically developing (TD) children. The expression levels of 13 miRNAs were evaluated with microfluidic qPCR, and differentially expressed (DE) mRNAs were detected on an Illumina HiSeq 2500 genome analyzer. The miRNA targetome was identified using an integrated approach of validated and predicted interaction data extracted from seven different bioinformatic tools. Gene Ontology (GO) and pathway enrichment analyses were carried out. Results showed that six miRNAs (miR-652-3p, miR-942-5p, let-7b-5p, miR-181a-5p, miR-320a, and miR-148b-3p) and 560 genes were significantly DE in children with ADHD compared to TD subjects. After correction for multiple testing, only three miRNAs (miR-652-3p, miR-148b-3p, and miR-942-5p) remained significant. Genes known to be associated with ADHD (e.g., B4GALT2, SLC6A9 TLE1, ANK3, TRIO, TAF1, and SYNE1) were confirmed to be significantly DE in our study. Integrated miRNA and mRNA expression data identified critical key hubs involved in ADHD. Finally, the GO and pathway enrichment analyses of all DE genes showed their deep involvement in immune functions, reinforcing the hypothesis that an immune imbalance might contribute to the ADHD etiology. Despite the relatively small sample size, in this study we were able to build a complex miRNA-target interaction network in children with ADHD that might help in deciphering the disease pathogenesis. Validation in larger samples should be performed in order to possibly suggest novel therapeutic strategies for treating this complex disease.

Neuroinflammation as a risk factor for attention deficit hyperactivity disorder

Attention Deficit Hyperactivity Disorder (ADHD) is a persistent, and impairing pediatric-onset neurodevelopmental condition. Its high prevalence, and recurrent controversy over its widespread identification and treatment, drive strong interest in its etiology and mechanisms. Emerging evidence for a role for neuroinflammation in ADHD pathophysiology is of great interest. This evidence includes 1) the above-chance comorbidity of ADHD with inflammatory and autoimmune disorders, 2) initial studies indicating an association with ADHD and increased serum cytokines, 3) preliminary evidence from genetic studies demonstrating associations between polymorphisms in genes associated with inflammatory pathways and ADHD, 4) emerging evidence that early life exposure to environmental factors may increase risk for ADHD via an inflammatory mechanism, and 5) mechanistic evidence from animal models of maternal immune activation documenting behavioral and neural outcomes consistent with ADHD. Prenatal exposure to inflammation is associated with changes in offspring brain development including reductions in cortical gray matter volume and the volume of certain cortical areas -parallel to observations associated with ADHD. Alterations in neurotransmitter systems, including the dopaminergic, serotonergic and glutamatergic systems, are observed in ADHD populations. Animal models provide strong evidence that development and function of these neurotransmitters systems are sensitive to exposure to in utero inflammation. In summary, accumulating evidence from human studies and animal models, while still incomplete, support a potential role for neuroinflammation in the pathophysiology of ADHD. Confirmation of this association and the underlying mechanisms have become valuable targets for research. If confirmed, such a picture may be important in opening new intervention routes.

Temperament correlates in adult ADHD: A systematic review★★

BACKGROUND

Attention deficit and hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder in children, but adult-ADHD is still an under-diagnosed and untreated condition. Treating adult-ADHD is complex and requires effective strategies for ADHD symptoms and comorbidities. Because of its high comorbidity rate with mood disorders and the growing interest in symptoms of emotional dysregulation in these patients, our aim was to collect studies that investigated temperament correlates in adult people with ADHD, to better understand the association between them and the eventual role of temperament as a prognostic-therapeutic marker.

METHODS

We performed a systematic review of the literature. We included only studies that measured temperament traits in ADHD adults using the Temperament Evaluation of Memphis, Paris and San Diego-Auto-questionnaire (TEMPS-A) or the Temperament and Character Inventory (TCI).

RESULTS

We retrieved 15 papers that used the TCI and 6 papers that used the TEMPS-A. In the TCI studies, ADHD was associated with high scores on Novelty Seeking and Harm Avoidance and low scores on Persistence. For the TEMPS-A studies, ADHD and Bipolar Disorders share some similarities in temperament scores, except for the hyperthymic temperament score.

LIMITATIONS

A comparison between the TCI and TEMPS-A results was not possible. The number of papers included was small. Among them, the type of sample, the number of recruited subjects and the ADHD assessment were very different.

CONCLUSIONS

The majority of ADHD individuals share temperament traits such as lability, irritability and excessiveness of emotional responses. Further research is needed to better understand whether temperament influences the pharmacological response of ADHD patients and whether temperament scores affect the long-term therapeutic outcome.

Relation Between Attention-Deficit Hyperactivity Disorder and IgE-Dependent Allergy in Pediatric Patients

Food allergy is a common condition in children and adolescent, remitting with time. Few clinical studies have emphasized the link between food allergies and psychosocial conditions, suggesting a profound impact of atopic diseases on the development of attention-deficit hyperactivity disorder (ADHD) in children. The objective of this study was to compile and assess available studies on the comorbidity or causality between ADHD and atopic food allergy in children. We discuss epidemiology, interrelated mechanisms, and potential dietary interventions in the management of children with ADHD.

Physical health in children with neurodevelopmental disorders

With increasing numbers of children being diagnosed with neurodevelopmental disorders (NDDs) attention has been drawn to these children's physical health. We aimed to identify the prevalence of defined physical problems (epilepsy, migraine, asthma, cancer, diabetes, psoriasis, lactose intolerance, celiac disease, diarrhea, constipation, daytime enuresis, encopresis) in a nationwide population of 9- and 12-year-old twins subdivided into those with and without indications of NDDs. Parents of 28,058 twins participated in a well-validated telephone interview regarding their children's mental health and answered questions about their physical problems. The results indicate a high rate of physical problems in children with NDDs, particularly in those with indications of the presence of combinations of several NDDs.

Asthma over the Adult Life Course: Gender and Hormonal Influences

Asthma is a common disorder that affects genders differently across the life span. Earlier in life, it is more common in boys. At puberty, asthma becomes more common and often more severe in girls and women. The effect of sex hormones on asthma incidence and its severity is difficult to differentiate from other asthma severity risk factors, such as racial background, socioeconomic factors, obesity, atopy, environmental exposure, and, in particular, lung aging. Recognizing gender-associated and age-associated differences is important to understanding the pathobiology of asthma and to providing effective education and personalized care for patients with asthma across the life course.

Association of epilepsy and asthma: a population-based retrospective cohort study

Background

Epidemiologic data supporting the epilepsy–asthma association are insufficient. Therefore, we examined this association in this study.

Methods

By using claims data from the National Health Insurance Research Database (Taiwan), we executed a retrospective cohort analysis. Analysis 1 entailed comparing 150,827 patients diagnosed as having incident asthma during 1996–2013 with disease-free controls who were selected randomly during the same period, frequency matched in terms of age and sex. Similarly, analysis 2 entailed comparing 25,274 patients newly diagnosed as having epilepsy with sex- and age-matched controls who were selected randomly. At the end of 2013, we evaluated in analysis 1 the epilepsy incidence and risk and evaluated in analysis 2 the asthma incidence and risk. We applied Kaplan–Meier analysis to derive plots of the proportion of asthma-free seizures.

Results

In analysis 1, the asthma group exhibited a higher epilepsy incidence than did the control group (3.05 versus 2.26 per 1,000 person-years; adjusted hazard ratio: 1.39, 95% CI [1.33–1.45]). We also noted a greater risk of subsequent epilepsy in women and girls. In analysis 2, we determined that the asthma incidence between the control and epilepsy groups did not differ significantly; however, some age subgroups including children and individuals in their 30s had an increased risk. A negative association was found in adolescents. The Kaplan–Meier analysis revealed epilepsy to be positively associated with subsequent onset of asthma within seven years of epilepsy diagnosis.

Discussion

Asthma may be associated with high epilepsy risk, and epilepsy may be associated with high asthma risk among children and individuals in their 30s. Nevertheless, people with epilepsy in other age subgroups should be aware of the possibility of developing asthma within seven years of epilepsy diagnosis.

Adult ADHD and Comorbid Somatic Disease: A Systematic Literature Review

OBJECTIVE

To systematically review, synthesize, and appraise available evidence, connecting adult ADHD with somatic disease.

METHOD

Embase, Psychinfo, and Medline databases were searched for studies published from 1994 to 2015 addressing adult ADHD and somatic comorbidity. Somatic conditions were classified according to International Classification of Diseases (ICD-10) codes. Levels of evidence were graded as inconclusive, tentative, or well documented.

RESULTS

Most of the 126 studies included in the qualitative synthesis were small and of modest quality. Obesity, sleep disorders, and asthma were well-documented comorbidities in adult ADHD. Tentative evidence was found for an association between adult ADHD and migraine and celiac disease. In a large health registry study, cardiovascular disease was not associated with adult ADHD.

CONCLUSION

There are few large systematic studies using standardized diagnostic criteria evaluating adult ADHD and somatic comorbidities. Significant associations are found between adult ADHD and several somatic diseases, and these are important to consider when assessing and treating either adult ADHD or the somatic diseases.

Attention-Deficit/Hyperactivity Disorder in Offspring of Mothers With Inflammatory and Immune System Diseases

BACKGROUND

Prenatal inflammatory mechanisms may play a role in the pathogenesis of psychiatric disorders and could be relevant for attention-deficit/hyperactivity disorder (ADHD). We investigated maternal chronic somatic diseases with immune components as possible risk factors for ADHD in offspring.

METHODS

We performed a population-based nested case-control study by linking data from longitudinal Norwegian registers. We included all individuals born during the period 1967-2008 and alive at record linkage (2012). Individuals receiving ADHD medication during the years 2004-2012 were defined as patients with ADHD (N = 47,944), and all remaining individuals (N = 2,274,713) were defined as control subjects. The associations between maternal diseases and ADHD in offspring were analyzed using logistic regression models.

RESULTS

The following chronic diseases with immune components were related to ADHD in offspring: multiple sclerosis (adjusted odds ratio [OR] = 1.8; 95% confidence interval [CI] = 1.2-2.5), rheumatoid arthritis (adjusted OR = 1.7; 95% CI = 1.5-1.9), type 1 diabetes (adjusted OR = 1.6; 95% CI = 1.3-2.0), asthma (adjusted OR = 1.5; 95% CI = 1.4-1.6), and hypothyroidism (adjusted OR = 1.2; 95% CI = 1.1-1.4). In contrast, chronic hypertension and type 2 diabetes showed no significant associations. Estimates were almost unchanged with additional adjustment for parental ADHD, infant birth weight, and gestational age. Although point estimates for male and female offspring were different for some diseases (e.g., maternal asthma [adjusted OR = 1.7; 95% CI = 1.5-1.8 for female offspring and adjusted OR = 1.5; 95% CI = 1.4-1.6 for male offspring]), none of the associations differed significantly by offspring sex.

CONCLUSIONS

Several maternal somatic diseases with immune components were found to increase the risk of ADHD in offspring. The associations could involve several causal pathways, including common genetic predisposition and environmental factors, and increased insight into the mechanisms behind these relationships could enhance our understanding of the etiology of ADHD.

Comorbidity of Allergic and Autoimmune Diseases Among Patients With ADHD

OBJECTIVE

Patients with ADHD have been suggested to have increased risks of allergic diseases but without consistent results, and limited studies about the association between ADHD and autoimmune diseases were noted in the literature.

METHOD

Utilizing the Taiwan National Health Insurance Research Database, ADHD patients were identified and compared with age- and gender-matched controls (1:4).

RESULTS

In all, 8,201 participants were identified as having ADHD, and an increased prevalence of allergic diseases, including asthma (odds ratio [OR] = 1.53), allergic rhinitis (OR = 1.59), atopic dermatitis (OR = 1.53), and urticaria (OR = 1.39), compared with the control group. Although the comorbidity of autoimmune diseases with ADHD was low, ADHD patients had a significantly greater prevalence of ankylosing spondylitis (OR = 2.78), ulcerative colitis (OR = 2.31), and autoimmune thyroid disease (OR = 2.53) than the controls.

CONCLUSION

Our results supported the association between ADHD and allergic/autoimmune diseases. The further studies will be required to clarify the underlying mechanisms.

Psychiatric disorders and symptoms severity in pre-school children with cow's milk allergy

BACKGROUND

Psychiatric disorders are seen frequently in atopic diseases. The present study aims to evaluate the frequency of psychiatric disorders and the severity of psychiatric symptoms in pre-school children with cow's milk allergy.

METHODS

The parents of the pre-school children with cow's milk allergy were interviewed in person and asked to fill out the Early Childhood Inventory-4 form.

RESULTS

The cow's milk allergy group included 40 children (27 male, 13 female) with mean age, 44.5±14.7 months, and the control group included 41 children (25 male, 16 female) with mean age, 47.6±15.2 months. It was established that 65% of the group with cow's milk allergy received at least one psychiatric diagnosis, while 36.6% of the control group received at least one psychiatric diagnosis, with a statistically significant difference (p=0.02). Within the psychiatric disorders, attention deficit hyperactivity disorders (odds ratio: 4.9, 95% CI: 1.472-16.856, p=0.006), oppositional defiant disorder (odds ratio: 5.6, 95% CI: 1.139-28.128, p=0.026), and attachment disorder (odds ratio: 4.8, 95% CI: 1.747-13.506, p=0.004) were found significantly higher compared with the healthy control group. When the groups were compared in terms of psychiatric symptom severity scores, calculated by using the Early Childhood Inventory-4 form, attention deficit hyperactivity disorders severity (p=0.006) and oppositional defiant disorder severity (p=0.037) were found to be higher in the cow's milk allergy group.

CONCLUSION

Psychiatric disorders are frequent and severe in pre-school children with cow's milk allergy.

Asthma is Different in Women

Gender differences in asthma incidence, prevalence and severity have been reported worldwide. After puberty, asthma becomes more prevalent and severe in women, and is highest in women with early menarche or with multiple gestations, suggesting a role for sex hormones in asthma genesis. However, the impact of sex hormones on the pathophysiology of asthma is confounded by and difficult to differentiate from age, obesity, atopy, and other gender associated environmental exposures. There are also gender discrepancies in the perception of asthma symptoms. Understanding gender differences in asthma is important to provide effective education and personalized management plans for asthmatics across the lifecourse.

Identification and association of relationships between selected personal and environmental factors and formal components of temperament and strategies of coping with stress in asthmatic patients

Background: Personal and environmental factors might have an impact on strategies of coping with stress and temperamental traits according to the Regulative Theory of Temperament in asthmatic patients. They can modify the clinical picture, the course of a disease and effectiveness of treatment. Personal variables are key factors in determining formal characteristic of behavior and effective management method in asthmatic patients. Aim of study: The aim of the study was to identify selected personal and environmental factors, as well as factors inducing attacks and asthma exacerbations or maintaining them in a complex of personal traits of patients. Methods: Two hundred and eighty one participants were included in the study. Of this number 122 subjects were healthy volunteers and 159 were asthmatic patients. In all the subjects the authors applied the Formal Characteristic of Behaviour – FCZ-KT – Temperament Inventory, Coping Inventory for Stressful Situations (CISS), Beck Depression Inventory, State-Trait Anxiety Inventory and Borg Rating of Perceived Exertion (RPE) Scale. Genotyping of polymorphic forms of NR3C1 gene was conducted with PCR-RFLP and PCR-HRM methods. Expression of TGFβ1 gene was measured with the use of qRT-PCR. Results: The authors confirmed a significant influence of personal and environmental factors, such as: age, height, body weight, sex, asthma exacerbations, drugs administered by patients, allergy and psychopathological variables on strategies of coping with stress by asthmatic patients (Task-Oriented Coping, Emotion-Oriented Coping, Avoidance-Oriented Coping, distraction seeking, social diversion). Temperamental traits (Briskness, Perseverance, Sensory Sensitivity, Emotional Reactivity, Endurance, Activity) depend on age, sex, body weight, genetic predispositions and they are modified by asthma exacerbations, allergy, drugs administered by patients, depression and anxiety (state and trait). The authors confirmed a correlation between Tth111I polymorphic form of NR3C1 gene and perseverance (p= 0.0450). It was noted that an increase in the TGFβ1 expression level led to a decrease in the patients' emotional reactivity (p= 0.0212). Conclusions: Strategies of coping with stress and temperamental traits according to the Regulative Theory of Temperament in asthmatic patients are determined by personal and environmental factors.

Genome-wide analysis of attention deficit hyperactivity disorder in Norway

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a highly heritable neuropsychiatric condition, but it has been difficult to identify genes underlying this disorder. This study aimed to explore genetics of ADHD in an ethnically homogeneous Norwegian population by means of a genome-wide association (GWA) analysis followed by examination of candidate loci.

MATERIALS AND METHODS

Participants were recruited through Norwegian medical and birth registries as well as the general population. Presence of ADHD was defined according to DSM-IV criteria. Genotyping was performed using Illumina Human OmniExpress-12v1 microarrays. Statistical analyses were divided into several steps: (1) genome-wide association in the form of logistic regression in PLINK and follow-up pathway analyses performed in DAPPLE and INRICH softwares, (2) SNP-heritability calculated using genome-wide complex trait analysis (GCTA) tool, (3) gene-based association tests carried out in JAG software, and (4) evaluation of previously reported genome-wide signals and candidate genes of ADHD.

RESULTS

In total, 1.358 individuals (478 cases and 880 controls) and 598.384 autosomal SNPs were subjected to GWA analysis. No single polymorphism reached genome-wide significance. The strongest signal was observed at rs9949006 in the ENSG00000263745 gene (OR=1.51, 95% CI 1.28-1.79, p=1.38E-06). Pathway analyses of the top SNPs implicated genes involved in the regulation of gene expression, cell adhesion and inflammation. Among previously identified ADHD candidate genes, prominent association signals were observed for SLC9A9 (rs1393072, OR=1.46, 95% CI = 1.21-1.77, p=9.95E-05) and TPH2 (rs17110690, OR = 1.38, 95% CI = 1.14-1.66, p=8.31E-04).

CONCLUSION

This study confirms the complexity and heterogeneity of ADHD etiology. Taken together with previous findings, our results point to a spectrum of biological mechanisms underlying the symptoms of ADHD, providing targets for further genetic exploration of this complex disorder.

Nutrition, immunological mechanisms and dietary immunomodulation in ADHD

Attention-deficit hyperactivity disorder (ADHD) etiology is not completely understood, but common comorbid dysfunction of the gastrointestinal and immune system suggests that these systems may be affected by a common genetic background and molecular mechanisms. For example, increased levels of specific cytokines were observed in ADHD. Moreover, ADHD has a high comorbidity with both Th1- and Th2-mediated disorders like ear infections, eczema and asthma. A common pathophysiological mechanism was suggested to underlie both asthma and ADHD, while several genes that are linked to ADHD have immune functions. Furthermore, immunological recognition of food provoking ADHD-like behavior was suggested. An immune imbalance, probably requiring a predisposing genetic background, is therefore suggested to contribute to ADHD etiology, with immune dysregulation being more likely than a single subcellular defect. However, next to allergic mechanisms, also pharmacological mechanisms (especially in case of food additives) might be involved. In addition, though cellular (cytokine-related) rather than antibody-mediated immune mechanisms seem involved, specific immune-inflammatory markers other than antibodies have not been systematically studied in ADHD. Substantial alterations implicated in ADHD apparently occur in the immune system and epigenetic regulation of gene expression. As a result, chronic inflammation and oxidative stress could develop, which can lead to ADHD symptoms, for example by chronic T-cell-mediated neuroinflammation. If immune pathways contribute to ADHD, both its diagnosis and treatment should be reconsidered. Modulation of immune system activity might have potential in ADHD treatment, for example by nutritional approaches providing safe and low-cost ADHD therapy, but further research in these fields is implicated.

Food allergy and food-based therapies in neurodevelopmental disorders

Autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) are neurodevelopmental disorders which occur in childhood and may persist into adulthood. Although the etiology of these disorders is largely unknown, genetic and environmental factors are thought to play a role in the development of ASD and ADHD. Allergic immune reactions, in prenatal and postnatal phases, are examples of these environmental factors, and adverse reactions to foods are reported in these children. In this review, we address the clinical and preclinical findings of (food) allergy in ASD and ADHD and suggest possible underlying mechanisms. Furthermore, opportunities for nutritional interventions in neurodevelopmental disorders are provided.

Higher risk of mood disorders among adolescents with ADHD and asthma: a nationwide prospective study

BACKGROUND

Attention-deficit hyperactivity disorder (ADHD) and asthma are commonly comorbid together, and are associated with an increased risk of development of mood disorders separately. However, there has been no study investigating the comorbid effect of these two disorders on developing mood disorder.

METHODS

Using the National Health Insurance Research Database, adolescents with ADHD-alone, asthma-alone, ADHD comorbid with asthma, and age-/gender-matched (1:4) controls were recruited in 2003. Subjects who developed major depression, any depressive disorder, or bipolar disorder during the follow-up period (2003-2010) were identified.

RESULTS

In all, 1172 adolescents with ADHD-alone, 487 with asthma-alone, 238 with ADHD+asthma, and 7552 controls were recruited in 2003. Adolescents with ADHD+asthma and those with ADHD-alone, but not those with asthma-alone, had an elevated risk of developing major depression (hazard ratio [HR]: 10.25, 95% confidence interval [CI]: 3.86-27.19; HR: 8.64, 95%CI: 5.00-14.93; HR: 2.11, 95%CI: 0.71-6.23) and bipolar disorder (HR: 31.25, 95%CI: 8.87-110.12; HR: 10.42, 95%CI: 4.60-23.63; HR: 1.91, 95%CI: 0.24-15.32) compared to the control group.

DISCUSSION

Our results showed that ADHD adolescents had an increased risk of developing both unipolar depression and bipolar depression in their later life, and that the comorbidity of asthma with a synergistic effect increased this risk further. The underlying pathophysiology among ADHD, asthma, and mood disorders needs further investigation.

Allergic disease is associated with epilepsy in childhood: a US population-based study

BACKGROUND

Previous studies using animal models suggest an association between allergic disease and epilepsy. We sought to determine whether allergic disease is associated with epilepsy in children.

METHODS

We used the 2007-2008 National Survey of Children's Health, a US population-based study of 91 642 children aged 0-17 years to determine the association between the prevalence of epilepsy and allergic disease, including asthma, atopic dermatitis (AD)/eczema, hay fever, and food allergies. Multivariate logistic regression models were constructed that controlled for confounding variables.

RESULTS

The US lifetime prevalence of childhood epilepsy was 1.03% and was significantly associated with older age, male sex, lower household income, family structure and history of brain injury or concussion. Children with ≥1 allergic disease had more epilepsy in their lifetime than nonallergic children (logistic regression, adjusted odds ratio [95% confidence interval] = 1.79 [1.37-2.33]). Lifetime prevalence (2.30 [1.50-3.52]) and one-year prevalence of asthma (2.00 [1.41-2.84]), AD/eczema (1.73 [1.17-2.56]), hay fever (1.93 [1.41-2.65]) and food allergies (2.69 [1.38-4.01]) were associated with increased odds of ever being diagnosed with epilepsy. Similar results were found for current history of epilepsy. Severe AD/eczema (3.89 [1.34-11.32]) [corrected] and hay fever (2.46 [1.11-5.41]) were associated with even higher odds of epilepsy compared with mild/moderate disease. As the number of allergic diseases increased, so did the odds of lifetime history and current history of epilepsy.

CONCLUSIONS

The US prevalence of epilepsy is associated with allergic diseases in children. Further studies are needed to determine whether allergic inflammation contributes toward epileptogenesis.

Attention-deficit/hyperactivity disorder, physical health, and lifestyle in older adults

OBJECTIVES

To increase insight into the effect of attention-deficit/hyperactivity disorder (ADHD) on health in general in older adults.

DESIGN

Two-phase sampling side-study.

SETTING

Longitudinal Aging Study Amsterdam (LASA).

PARTICIPANTS

Two hundred twenty-three randomly selected LASA respondents.

MEASUREMENTS

Information was collected during home visits on physical health, medication use, and lifestyle characteristics in Phase 1 and on ADHD diagnosis in Phase 2. The associations between independent variables and ADHD were examined with linear and logistic regression analyses.

RESULTS

The adjusted regression estimates of the linear regression analysis showed that the number of ADHD symptoms was positively associated with the presence of chronic nonspecific lung diseases (CNSLD) (B = 2.58, P = .02), cardiovascular diseases (B = 2.18, P = .02), and number of chronic diseases (B = 0.69, P = .04) and negatively associated with self-perceived health (B = -2.83, P = .002). Lifestyle is not a mediator of the association between ADHD and physical health.

CONCLUSION

Attention-deficit/hyperactivity disorder in older adults was associated with chronic physical illness and poorer self-perceived health. Contrary to expectations, there were no associations between symptoms of ADHD and lifestyle variables.

Attention deficit hyperactivity disorder, tic disorder, and allergy: is there a link? A nationwide population-based study

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) and tic disorder usually co-occur in the same individuals, but the underlying mechanisms remain unclear. Previous evidence has shown that a frequent coexistence of allergic diseases was noted in patients with ADHD or tic disorder. We attempted to investigate the possible link among ADHD, tic disorder, and various allergic diseases.

METHODS

Utilizing the Taiwan National Health Insurance Research Database from 1996 to 2010, 5,811 patients with ADHD alone, 1,816 patients with tic disorder alone, and 349 patients with dual diagnoses of ADHD and tic disorder were identified and compared with age-/gender-matched controls (1:4) in an investigation of the association among ADHD, tic disorder, and allergic diseases.

RESULTS

Patients with dual diagnoses of ADHD and tic disorder had a significantly higher prevalence of allergic diseases and psychiatric comorbidities, including allergic rhinitis (43% vs. 28.4% vs. 33.6% vs. 19.7%, p < 0.001), asthma (27.5% vs. 17.2% vs. 18.2% vs. 11.9%, p < 0.001), atopic dermatitis (10.6% vs. 8.4% vs. 7.0 vs. 5.9%, p < 0.001), allergic conjunctivitis (55.6% vs. 34.7% vs. 43.5% vs. 26.3%, p < 0.001), obsessive compulsive disorder (4.0% vs. 1.3% vs. 2.0% vs. 0.1%, p < 0.001), and anxiety disorder (22.1% vs. 18.0% vs. 6.0% vs. 0.5%, p < 0.001) than the ADHD alone group, the tic alone group, and the control group. Furthermore, ADHD patients with more allergic diseases (≥ 3 comorbidities: OR: 3.73, 95% CI: 2.65~5.25; 2 comorbidities: OR: 2.52, 95% CI: 1.82~3.47; 1 comorbidity: OR: 1.87, 95% CI: 1.41~2.49) exhibited an increased risk of tic disorder compared with ADHD patients without allergic disease.

CONCLUSION

  A significant association among ADHD, tic disorder, and allergic diseases was noted in our study. The results may inspire further studies to clarify the underlying mechanisms and help us understand more about the complex etiology of ADHD, tic disorder, and their co-occurrence.

Adolescent ADHD and adult physical and mental health, work performance, and financial stress

OBJECTIVE

There is a scarcity of longitudinal studies of adolescents with attention-deficit/hyperactivity disorder (ADHD) followed until adulthood. We studied the relationship between ADHD in adolescence and impaired general physical health, impaired general mental health, antisocial personality disorder, impaired work performance, and high financial stress in adulthood.

METHODS

A prospective design incorporated 6 assessments of participants spanning mean ages from 14 to 37 years. Two baseline assessments were taken between ages 14 and 16 years, and 5 outcome assessments were taken at mean age 37 years. Participants were assessed with structured interviews and questionnaires. The participants were from a community sample of individuals initially drawn in 1975 and followed to a mean age of 37 years in 2009.

RESULTS

The adjusted odds ratios and 95% confidence intervals (CIs) for ADHD in adolescence as related to internal stress in adulthood were 1.82 (95% CI = 1.01-3.25; P < .05) for impaired general physical health, 2.36 (95% CI = 1.23-4.51; P < .01) for impaired general mental health, and 3.28 (95% CI = 1.51-7.13; P < .01) for antisocial personality disorder. The adjusted odds ratios and 95% CIs for ADHD in adolescence as related to external stress were 2.46 (95% CI = 1.37-4.43; P < .01) for impaired work performance and 3.33 (95% CI = 1.70-6.55; P < .001) for high financial stress.

CONCLUSIONS

Clinicians should focus on early diagnosis and treatment of adolescent ADHD because it is a major predictor of an array of physical, mental, work, and financial problems in adulthood.