Pathogenesis Of Attention Deficit Hyperactivity Disorder Research Articles

Acetylcholine-metabolizing butyrylcholinesterase (BCHE) copy number and single nucleotide polymorphisms and their role in attention-deficit/hyperactivity syndrome

A previous genome-wide screen for copy number variations (CNVs) in attention deficit/hyperactivity disorder (ADHD) revealed a de novo chromosome 3q26.1 deletion in one of the patients. Candidate genes at this locus include the acetylcholine-metabolizing butyrylcholinesterase (BCHE) expressing gene (OMIM #177400), which is of particular interest. The present study investigates the hypothesis that the heterozygous deletion of the BCHE gene is associated with adult ADHD (aADHD). Ina first step, we screened 348 aADHD patients and 352 controls for stretches of loss of heterozygosity (LOH) across the entire BCHE gene to screen for the deletion. Our second aim was to clarify whether BCHE single nucleotide polymorphisms (SNPs) themselves influence the risk towards ADHD. Putative functional consequences of associated SNPs as well as their un-typed proxies were predicted by several bioinformatic tools. 96 individuals displayed entirely homozygous genotype reads in all 12examined SNPs, making them possible candidates to harbor a heterozygous BCHE deletion. DNA from these 96 probands was further analyzed by real-time PCR using a BCHE-specific CNV assay. However, no deletion was found. Of the 12 tag SNPs that passed inclusion criteria, rs4680612 and rs829508were significantly associated with aADHD, as their minor alleles occurred more often in cases than in controls (p = 0.018 and p = 0.039, respectively). The risk variant rs4680612 is located in the transcriptional control region of the gene and predicted to disrupt a binding site for MYT-1, which has previously been associated with mental disorders. However, when examining a second independent adult ADHD sample of 353 cases, the association did not replicate. When looking up the deletion in three genome-wide screens for CNV in ADHD and combining it with the present study, it became apparent that 3 from a total of 1030 ADHD patients, but none of 5787 controls, featured a deletion of the BCHE promoter region including rs4680612 (p = 0.00004). Taken together, there are several lines of evidence suggesting a potential involvement of BCHE in the etiopathology of ADHD, as a rare hemizygous deletion as well as a common SNP in the same region are associated with disease, although with different penetrance. Both variations result in the disruption of the binding site of the transcription factor MYT-1 suggesting epistatic effects of BCHE and MYT-1 in the pathogenesis of ADHD. As we were not able to replicate the SNP association, our findings should be considered preliminary and call for larger studies in extended phenotypes.

Changes in plasma Brain-derived neurotrophic factor (BDNF) levels induced by methylphenidate in children with Attention deficit–hyperactivity disorder (ADHD)

It has been suggested that BDNF may play a role in the pathogenesis of ADHD. Our aim is to determine whether methylphenidate can induce changes in plasma BDNF levels of children with ADHD. We assessed levels of plasma BDNF in 28 ADHD patients (age range = 3.5-10 years) before and after 6 weeks treatment with effective dosages of methylphenidate. Then we evaluated the correlation of levels of plasma BDNF with clinical variables, especially ADHD Conner's parents rating scale. According to the paired sample T-test, the mean plasma BDNF level in the baseline was 193.06 pg/ml, whereas 271.06 pg/ml in the end point, thus showing significantly higher mean plasma BDNF levels in the post-treatment situation than in the pretreatment (t = -3.393, df = 27, p = 0.002). Pearson's correlation test revealed that there was also significant negative correlation between levels of BDNF in the plasma of ADHD patients before treatment and improvement in hyperactivity symptoms with treatment (Pearson's correlation = -0.395, p = 0.037). The mean plasma BDNF levels increased after 6 weeks of treatment with methylphenidate. Also, we found an improvement in hyperactivity symptoms with decreasing baseline plasma BDNF levels. We recommend that more studies should be conducted in order to assess the possible roles of plasma BDNF levels in treatment response prediction and prognosis.

Functional Properties of Rare Missense Variants of Human CDH13 Found in Adult Attention Deficit/Hyperactivity Disorder (ADHD) Patients

The CDH13 gene codes for T-cadherin, a GPI-anchored protein with cell adhesion properties that is highly expressed in the brain and cardiovascular system. Previous studies have suggested that CDH13 may be a promising candidate gene for Attention Deficit/Hyperactivity Disorder (ADHD). The aims of this study were to identify, functionally characterize, and estimate the frequency of coding CDH13 variants in adult ADHD patients and controls. We performed sequencing of the CDH13 gene in 169 Norwegian adult ADHD patients and 63 controls and genotyping of the identified variants in 641 patients and 668 controls. Native and green fluorescent protein tagged wild type and variant CDH13 proteins were expressed and studied in CHO and HEK293 cells, respectively. Sequencing identified seven rare missense CDH13 variants, one of which was novel. By genotyping, we found a cumulative frequency of these rare variants of 2.9% in controls and 3.2% in ADHD patients, implying that much larger samples are needed to obtain adequate power to study the genetic association between ADHD and rare CDH13 variants. Protein expression and localization studies in CHO cells and HEK293 cells showed that the wild type and mutant proteins were processed according to the canonical processing of GPI-anchored proteins. Although some of the mutations were predicted to severely affect protein secondary structure and stability, no significant differences were observed between the expression levels and distribution of the wild type and mutant proteins in either HEK293 or CHO cells. This is the first study where the frequency of coding CDH13 variants in patients and controls is reported and also where the functional properties of these variants are examined. Further investigations are needed to conclude whether CDH13 is involved in the pathogenesis of ADHD or other conditions.

No association between MspI allele of the ADRA2A polymorphism and ADHD

There is evidence for a genetic contribution to attention-deficit hyperactivity disorder (ADHD), although no candidate genes have attained genome-wide significance to date. Given that the noradrenergic system has been implicated in ADHD, the gene for the α2-adrenergic receptor (ADRA2A) has been hypothesized to contribute to the pathogenesis of ADHD. The present investigation reports results from a meta-analysis of family-based studies that did not find a significant association between the MspI polymorphism of the ADRA2A gene and ADHD.

Decreased serum levels of brain-derived neurotrophic factor in adults with attention-deficit hyperactivity disorder

It has been hypothesized that brain-derived neurotrophic factor (BDNF) is involved in the pathogenesis of attention-deficit hyperactivity disorder (ADHD), although experimental data regarding the contribution of BDNF gene polymorphisms to this psychiatric disorder are controversial. Recently, changes in BDNF serum levels have been reported in children with ADHD, but there are no studies about the possible role of this neurotrophin in adults. A total of 54 Caucasoid ADHD adults, including the predominantly inattentive and combined types (aged 33.43±8.99 yr) and 59 Caucasoid unrelated healthy controls (aged 35.52±9.37 yr) were included in a study to evaluate BDNF levels in serum. Medical, neurological and psychiatric co-morbidities were excluded. Clinical data concerning ADHD diagnosis and blood samples for patients and controls were collected. BDNF serum levels were significantly lower in adults with ADHD compared to healthy controls (p<0.0001). Although the combined type of ADHD subgroup displayed lower BDNF serum levels than the inattentive type, the differences did not reach statistical significance. No significant correlations were found between serum BDNF levels and scores on the Conners' Adult ADHD Rating Subscales. These results suggest a role for BDNF in ADHD, at least in those patients whose disorder persists throughout life. Low BDNF levels may contribute to the neurodevelopmental deficits of ADHD and to the persistence of the disorder into adulthood. BDNF differences between ADHD subtypes should be further studied.

The role of Homer 1a in increasing locomotor activity and non-selective attention, and impairing learning and memory abilities

The current study aimed to investigate the possible role of Homer 1a in the etiology and pathogenesis of attention deficit hyperactivity disorder (ADHD). We divided 32 rats into four groups. The rats in the RNAi-MPH group were given the lentiviral vector containing Homer 1a-specific miRNA (Homer 1a-RNAi-LV) by intracerebroventricular injection, and 7 days later they were given three daily doses of methylphenidate (MPH) by intragastric gavage. The RNAi-SAL group was given Homer 1a-RNAi-LV and saline later. The NC-MPH group was given the negative control lentiviral vector (NC-LV) and MPH later. The NC-SAL group was given NC-LV and saline later. Rats that were given Homer 1a RNAi exhibited increased locomotor activity and non-selective attention, and impaired learning and memory abilities, which is in line with the behavioral findings of animal models of ADHD. However, MPH ameliorated these abnormal behaviors. All findings indicated that Homer 1a may play an important role in the etiology and pathogenesis of ADHD.

Behavioural effects of monoamine reuptake inhibitors on symptomatic domains in an animal model of attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is a heterogeneous neurobehavioural disorder. Several lines of evidence have implicated monoamine signalling systems, including transporters and receptors, in the pathogenesis of ADHD. We explored the heterogeneity of neural mechanisms that may possibly underlie symptomatic abnormalities in ADHD, by investigating the effects of monoamine reuptake inhibitors with differential spectrums for each monoamine transporter on ADHD-like behaviours in an animal model of ADHD, i.e. juvenile (6-week-old) male stroke-prone spontaneously hypertensive rats (SHRSP/Ezo). The impaired spontaneous alternation performance in a Y-maze task, demonstrated the inattentive features of SHRSP/Ezo, was improved by a selective DA reuptake inhibitor GBR-12909 (1 and 3mg/kg, i.p.). Desipramine (1, 3 and 10mg/kg, i.p.) and milnacipran (30mg/kg, i.p.), which possess a noradrenaline (NA) reuptake inhibitory activity, also ameliorated inattentive behaviour. Increased locomotor activity in open-field apparatus and total arm entries in a Y-maze task, which demonstrate the hyperactive features of SHRSP/Ezo, were improved by desipramine and milnacipran, but impaired by a high dose of GBR-12909 (10mg/kg, i.p.). A selective serotonin (5-HT) reuptake inhibitor fluvoxamine (10 and 30mg/kg, i.p.), did not affect inattention but significantly suppressed hyperactivity at a high dose (30mg/kg, i.p.). Moreover, a low dose of fluvoxamine (3mg/kg, i.p.) ameliorated the increased open arm spent time in an elevated plus-maze without affecting total arm entries, indicating an effect on impulsive features based on the anxiolytic characteristics of SHRSP/Ezo.These behavioural effects of monoamine reuptake inhibitors support the heterogeneity of monoaminergic systems, which are responsible for ADHD-like behaviours in SHRSP/Ezo. These findings may provide pharmacological evidence for the development of ADHD treatments that target more appropriate monoamine transporters.

Metabolic correction for attention deficit/hyperactivity disorder: A biochemical-physiological therapeutic approach

Objective: This investigation was undertaken to determine the reference values of specific biochemical markers that have been have been associated with behavior typical of ADHD in a group of patients before and after metabolic correction.Background: Attention deficit hyperactivity disorder (ADHD) affects approximately two million American children, and this condition has grown to become the most commonly diagnosed behavioral disorder of childhood. According to the National Institute of Mental Health (NIMH), the cause of the condition, once called hyperkinesis, is not known. The cause of ADHD is generally acknowledged to be multifactorial, involving both biological and environmental influence. Molecular, genetic, and pharmacological studies suggest the involvement of the neurotransmitter systems in the pathogenesis of ADHD. Polymorphic variants in several genes involved in regulation of dopamine have been identified, and related neurotransmitter pathways alterations are reported to be associated with the disease. Nutritional deficiencies, including deficiencies in fatty acids (EPA, DHA), the amino acid methionine, and the trace minerals zinc and selenium, have been shown to influence neuronal function and produce defects in neuronal plasticity, as well as impact behavior in children with attention deficit hyperactivity disorder. Materials/Methods: This study was based on data extracted from our patient history database covering a period of over ten years. We performed laboratory tests in 116 patients 2.7-25 years old with a diagnosis of ADHD. Sixty-six percent (66%) of patients were males. Patients were followed from 3 month to 3 years. We compared the distributions of fatty acids, essential metals, and the levels of metabolic stress factors with established reference ranges before and after interventions. In addition, we analyzed the association between toxic metal concentrations and the levels of essential metals.Results: This study was based on data extracted from our patient history database covering a period of over ten years. We performed laboratory tests in 116 patients 2.7-25 years old with a diagnosis of ADHD. Sixty-six percent (66%) of patients were males. Patients were followed from 3 month to 3 years. We compared the distributions of fatty acids, essential metals, and the levels of metabolic stress factors with established reference ranges before and after interventions. In addition, we analyzed the association between toxic metal concentrations and the levels of essential metals. According to these data, the metabolic correction of ADHD by supplementation with minerals, vitamins, essential fatty acids, and amino acids can ameliorate ADHD symptoms. Eighty percent (80%) of children who were treated from several weeks to 1-2 years, demonstrated improvement of metabolic stress level, measured by pyrroles. For these patients the levels of EPA were increased and the omega-6/omega-3 ratio was improved. Conclusion: In the studied population it was demonstrated that metabolic correction of biochemical disturbances using essential fatty acids, amino acids, and minerals can improve fatty acid profiles and metabolic stress levels. These disturbances or variations from reference values have been associated with behavior typical of ADHD. Further studies need to be conducted with integrative metabolic correction therapy to determine its value in the management of ADHD.Key words: Attention deficit hyperactivity disorder, metabolic correction, fatty acid composition, essential metals, toxic metals, pyrroles, vitamins and minerals.

Increased Locomotor Activity and Non-Selective Attention and Impaired Learning Ability in SD Rats after Lentiviral Vector-Mediated RNA Interference of Homer 1a in the Brain

Our previous studies found that Homer 1a, a scaffolding protein localized at the post-synaptic density (PSD) of glutamatergic excitatory synapses, is significantly down-regulated in the brain of spontaneous hypertensive rats (SHR), an animal model of attention deficit hyperactivity disorder (ADHD). Furthermore, a first-line treatment drug for ADHD, methylphenidate, can up-regulate the expression of Homer 1a. To investigate the possible role of Homer 1a in the etiology and pathogenesis of ADHD, a lentiviral vector containing miRNA specific for Homer 1a was constructed in this study. Intracerebroventricular injection of this vector into the brain of Sprague Dawley (SD) rats significantly decreased Homer 1a mRNA and protein expression levels. Compared to their negative controls, these rats displayed a range of abnormal behaviors, including increased locomotor activity and non-selective attention and impaired learning ability. Our results indicated that Homer 1a down-regulation results in deficits in control over behavioral output and learning similar to ADHD.

Association study between the dopamine-related candidate gene polymorphisms and ADHD among Saudi Arabia population via PCR technique

Attention deficit hyperactivity disorder (ADHD) is one of the most common childhood behavioral disorders characterized by inattention, hyperactivity and impulsivity. In Saudi Arabia the prevalence of combined ADHD is 16.4 %. ADHD etiology is not clear and not completely understood. There are several evidences for involvement of dopaminergic, serotonergic and noradrenergic neurotransmitter systems in the pathogenesis of ADHD. Monoamine Oxidase A (MAOA) is involved in the degradation of all three of these neurotransmitters. Dopamine Transporter 1 (DAT1) plays an important role in controlling blood levels of dopamine. The aim of the present study is to investigate the association between ADHD and polymorphisms of MAOA 30 bp-promoter VNTR and DAT1 40 bp 3' UTRVNTR in Saudi population. PCR technique was employed to detect polymorphisms of MAOA and DAT1 genes in a sample of 120 ADHD subjects and 160 controls. Alleles and genotypes frequencies for both of MAOA and DAT1 polymorphisms were compared among ADHD subjects against controls. Association between ADHD and alleles as well as genotypes for each studied polymorphisms was tested by odds ratio (OR) test and the magnitude of this association was estimated by 95 % confidence interval (95 % CI). A significant association was found between two MAOA genotypes 3/4 and 3/2 with ADHD (P < 0.01, OR = 3, 4.9) as a risk effect. No significant association was found with MAOA alleles. Among DAT1 polymorphisms two alleles (7 and 11 repeats) (P < 0.01, OR = 2.5 and 3.3) as well as two genotypes (11/11 and 11/7) (P < 0.01, OR = 4, 3) showed significant association with ADHD as a risk effect. On the contrary, 9 and 10 repeats revealed significant association as a protective effect as well as 10/10 and 10/9 genotypes. These findings support the hypothesis that some of the MAOA and DAT1 polymorphisms have a causative role in the development of ADHD in the Saudi population. Another polymorphism did not give rise to support this hypothesis. This is the first report investigated the association between MAOA and DAT1 polymorphism at molecular level in Saudi Arabia population as well as Arab world. Therefore further studies are needed to generalize obtained results at Saudi Arabia.

Dances with black widow spiders: Dysregulation of glutamate signalling enters centre stage in ADHD

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder with impairments across the lifespan. The persistence of ADHD is associated with considerable liability to neuropsychiatric co-morbidity such as depression, anxiety and substance use disorder. The substantial heritability of ADHD is well documented and recent genome-wide analyses for risk genes revealed synaptic adhesion molecules (e.g. latrophilin-3, LPHN3; fibronectin leucine-rich repeat transmembrane protein-3, FLRT3), glutamate receptors (e.g. metabotropic glutamate receptor-5, GRM5) and mediators of intracellular signalling pathways (e.g. nitric oxide synthase-1, NOS1). These genes encode principal components of the molecular machinery that connects pre- and postsynaptic neurons, facilitates glutamatergic transmission, controls synaptic plasticity and empowers intersecting neural circuits to process and refine information. Thus, identification of genetic variation affecting molecules essential for the formation, specification and function of excitatory synapses is refocusing research efforts on ADHD pathogenesis to include the long-neglected glutamate system.

What Causes ADHD?

Attention-deficit hyperactivity disorder (ADHD) is the most common childhood neurobehavioral disorder, and often co-occurs with psychiatric (ie, anxiety, depression, oppositional defiant, or conduct), developmental (ie, learning and language or autism spectrum), and physical disorders (ie, tics, sleep apnea).1 A spate of recent articles reveals the complexity and conundrums of diagnosis and therapy. Thapar and colleagues from the Department of Psychological Medicine and Neurology and the MRC Centre in Neuropsychiatric Genetics and Genomics at Cardiff University, United Kingdom reviewed the literature on the causes of ADHD.2 They report that genetic studies have yielded largely inconsistent results but that genes regulating dopaminergic pathways appear to be involved in the pathogenesis of ADHD. Functional polymorphism in …

Role of Dopamine Receptors in ADHD: A Systematic Meta-analysis

The dopaminergic system plays a pivotal role in the central nervous system via its five diverse receptors (D1-D5). Dysfunction of dopaminergic system is implicated in many neuropsychological diseases, including attention deficit hyperactivity disorder (ADHD), a common mental disorder that prevalent in childhood. Understanding the relationship of five different dopamine (DA) receptors with ADHD will help us to elucidate different roles of these receptors and to develop therapeutic approaches of ADHD. This review summarized the ongoing research of DA receptor genes in ADHD pathogenesis and gathered the past published data with meta-analysis and revealed the high risk of DRD5, DRD2, and DRD4 polymorphisms in ADHD.

Fluid reasoning deficits in children with ADHD: Evidence from fMRI

Attention-Deficit/Hyperactivity Disorder (ADHD) is associated with deficits in fluid reasoning, which may be related to self-regulation of cognition and behavior, and requires intact attention, working memory, and inhibition skills. No functional magnetic resonance imaging (fMRI) studies have directly examined fluid reasoning in ADHD which is surprising given that studies demonstrate a consistent network of brain regions involved in fluid reasoning that are also implicated in the pathogenesis of ADHD. Twenty-two right-handed, non-medicated children (12 ADHD, 10 controls) ages 8–12years completed a fluid reasoning task during which fMRI data were collected. The primary comparison of interest was activation during the fluid reasoning compared to the control condition. Behavioral data showed that children with ADHD tended to be less accurate with faster reaction times in the fluid reasoning condition compared to controls, and were significantly less accurate in the control condition. Controls activated more than participants with ADHD in the right intraparietal sulcus and the left lateral cerebellum in the fluid reasoning condition. Results showed hypoactivation in ADHD in regions critical for fluid reasoning. These results add to the literature suggesting a role for parietal and cerebellar regions in cognition and ADHD.

The sleep phenotypes of attention deficit hyperactivity disorder: The role of arousal during sleep and implications for treatment

About 25–50% of children and adolescents with attention-deficit hyperactivity disorder (ADHD) experience sleep problems. An appropriate assessment and treatment of such problems might improve the quality of life in such patients and reduce both the severity of ADHD and the impairment it causes. According to data in the literature and to the overall complexity of the interaction between ADHD and sleep, five sleep phenotypes may be identified in ADHD: (i) a sleep phenotype characterized mainly by a hypo-arousal state, resembling narcolepsy, which may be considered a “primary” form of ADHD (i.e. without the interference of other sleep disorders); (ii) a phenotype associated with delayed sleep onset latency and with a higher risk of bipolar disorder; (iii) a phenotype associated with sleep disordered breathing (SDB); (iv) another phenotype related to restless legs syndrome (RLS) and/or periodic limb movements; (v) lastly, a phenotype related to epilepsy/or EEG interictal discharges.Each sleep phenotype is characterized by peculiar sleep alterations expressed by either an increased or decreased level of arousal during sleep that have important treatment implications. Treatment with stimulants is recommended above all in the primary form of ADHD, whereas treatment of the main sleep disorders or of co-morbidities (i.e. bipolar disorders and epilepsy) is preferred in the other sleep phenotypes. All the sleep phenotypes, except the primary form of ADHD and those related to focal benign epilepsy or focal EEG discharges, are associated with an increased level of arousal during sleep. Recent studies have demonstrated that both an increase and a decrease in arousal are ascribable to executive dysfunctions controlled by prefrontal cortical regions (the main cortical areas implicated in the pathogenesis of ADHD), and that the arousal system, which may be hyperactivated or hypoactivated depending on the form of ADHD/sleep phenotype.

EEG characteristics and visual cognitive function of children with attention deficit hyperactivity disorder (ADHD)

Using visual and auditory continuous performance tests (CPT) and EEG, cognitive function and EEG power were investigated in patients with attention deficit hyperactivity disorder (ADHD). CPT and EEG were conducted for 44 ADHD children and 44 healthy controls of comparable age and sex. The EEG power tests include relative power of theta, alpha, and beta, and theta/beta and theta/alpha ratios. ADHD patients showed significantly higher theta relative power, lower beta relative power, and higher theta/beta ratio (p<0.05). ADHD patients showed a significantly lower score of auditory CPT (p<0.05). The EEG power characteristics were correlated significantly with the visual attention function in ADHD children (p<0.01). Higher-order level cognitive dysfunction affects ADHD pathogenesis. Cortical hypoarousal effects on several mechanisms including the fronto-striatal circuitry may be implicated in the inhibition of prepotent and premature responses.

Investigating the Contribution of Common Genetic Variants to the Risk and Pathogenesis of ADHD

Objective:A major motivation for seeking disease-associated genetic variation is to identify novel risk processes. Although rare copy number variants (CNVs) appear to contribute to attention deficit hyperactivity disorder (ADHD), common risk variants (single-nucleotide polymorphisms [SNPs]) have not yet been detected using genome-wide association studies (GWAS). This raises the concern as to whether future larger-scale, adequately powered GWAS will be worthwhile. The authors undertook a GWAS of ADHD and examined whether associated SNPs, including those below conventional levels of significance, influenced the same biological pathways affected by CNVs.Method:The authors analyzed genome-wide SNP frequencies in 727 children with ADHD and 5,081 comparison subjects. The gene sets that were enriched in a pathway analysis of the GWAS data (the top 5% of SNPs) were tested for an excess of genes spanned by large, rare CNVs in the children with ADHD.Results:No SNP achieved genome-wide significance levels. As previously reported in a subsample of the present study, large, rare CNVs were significantly more common in case subjects than comparison subjects. Thirteen biological pathways enriched for SNP association significantly overlapped with those enriched for rare CNVs. These included cholesterol-related and CNS development pathways. At the level of individual genes, CHRNA7, which encodes a nicotinic receptor subunit previously implicated in neuropsychiatric disorders, was affected by six large duplications in case subjects (none in comparison subjects), and SNPs in the gene had a gene-wide p value of 0.0002 for association in the GWAS.Conclusions:Both common and rare genetic variants appear to be relevant to ADHD and index-shared biological pathways.

Early Developmental Cues for Diagnosis of Attention Deficit/Hyperactivity Disorder in Young Children

Attention deficit hyperactivity disorder (ADHD) is a childhood-onset disorder that is considered one of the most common neurobehavioral disorders. The symptoms of ADHD should be cast, not as static or fixed neurobehavioral deficits, but rather in terms of underlying developmental processes. Targeting attentional disorders early in life can bring about fundamental alterations in the pathogenesis of ADHD, and thus prevent or moderate the course of the disorder. The developmental approach can enable predictions concerning characteristics of ADHD that develop over time and inform us about multiple risk and protective factors that transact to impact its development, as well as the development of a broad range of associated co-morbid features. In this review, we describe the complex factors that predict and mediate the developmental course of ADHD, providing early cues for ADHD diagnosis and intervention in young children that will optimize outcome.

Altered Biochemical Parameters in Saliva of Pediatric Attention Deficit Hyperactivity Disorder

Oxidative stress is one of the common causes in etiopathogenesis of attention deficit hyperactivity disorder (ADHD). Hence, the salivary levels of protein thiols, ceruloplasmin, magnesium and pseudocholinesterase were estimated in children with ADHD. The symptoms of ADHD were identified using Conner's rating and DSM IV criteria. Saliva was collected and assessed for the levels of protein thiols, ceruloplasmin, magnesium and pseudocholinesterase, spectrophotometrically. It was also checked for pH and the flow rate was noted down. There was a significant increase (P < 0.001) in the salivary protein thiols and pseudocholinesterase levels in ADHD children when compared to controls. Ceruloplasmin levels did not show any significant change. Magnesium levels were significantly decreased (P < 0.001) in cases when compared to controls. Further, a receiver operating characteristic curve for validity of the biochemical parameters in saliva of ADHD children indicated a sensitivity and specificity above 90% for protein thiols and magnesium values. Our study shows that protein thiols, magnesium, and pseudocholinesterase might have a role in the pathogenesis of ADHD and saliva can be effectively used as a non-invasive tool for evaluation of such children.

Communications orales du dimanche 16 octobre

Attention deficit/hyperactivity disorder (ADHD) is a childhood-onset psychiatric condition characterized by hyperactivity, impulsivity, and attention deficit. In addition to these core symptoms, accumulating evidence suggests that ADHD may also involve alterations in circadian rhythms, sleep disturbance, and time perception. The habenula is a brain region transmitting limbic information to the midbrain monoamine systems and is thereby involved in the regulation of monoamine release in such target brain areas as the striatum, where it is part of the biological substrates that process time perception. The habenula is additionally a part of the circadian rhythm network and is involved in sleep regulation. Our recent study provides a new insight that a habenula lesion created early in development produces behavioral and brain alterations resembling those observed in ADHD. We propose that the habenula may be a promising target for understanding the pathogenesis of ADHD.