Homer 1a RNA干扰后大鼠脑组织突触超微结构变化

目的 观察Homer 1a RNA干扰(RNAi)后SD大鼠脑组织突触数目及突触超微结构的变化,探讨其变化在注意缺陷多动障碍(ADHD)发病机制中的作用.方法 将24只SD大鼠随机分为2组:Homer 1a RNAi组(RNAi组,n=12)和对照组(n=12).运用侧脑室注射技术,分别向2组大鼠的侧脑室注射针对Homer 1a的RNA干扰病毒和无义病毒,等待病毒起效时间为7d,7d后从每组大鼠中随机抽取3只,应用8g·L-1多聚甲醛灌注固定脑组织,利用电镜技术观察大鼠纹状体及前额叶皮质突触超微结构的变化.结果 电镜结果显示,RNAi组与对照组相比,纹状体突触间隙显著减小(t=2.85,P=0.01);突触活性区长度有增大趋势,但差异无统计学意义(t=1.80,P=0.08);突触数目(t=0.59,P=0.57)及突触后致密物厚度(t=0.30,P=0.77)无明显差异.RNAi组前额叶皮质较对照组突触活性区长度显著增大(t =2.40,P=0.02);突触后致密物厚度(t=1.72,P=0.09)有增大趋势,但差异无统计学意义;突触数目(t=0.13,P=0.89)及突触间隙(=0.25,P=0.81)无明显差异.结论 Homer 1a RNAi大鼠在表现类似ADHD行为的同时,脑组织突触超微结构发生改变,提示Homer 1a参与的突触超微结构改变可能与ADHD的病因和发病机制相关.     

Delay aversion in attention deficit/hyperactivity disorder is mediated by amygdala and prefrontal cortex hyper‐activation

Background

Experimental research supports delay aversion as a motivational feature of attention deficit/hyperactivity disorder (ADHD). To investigate the neurobiology of delay aversion in ADHD, this study examined whether adolescents with ADHD display an unusually strong activation in affective brain regions in response to cues predicting forthcoming delay and whether these effects are (a) delay‐dose dependent and (b) statistically mediate the association between ADHD and self‐reported delay aversion.

Methods

Twenty‐nine right‐handed male adolescents with combined type ADHD and 32 typically developing controls (ages 10–18 years) performed a reaction time task in an MRI scanner. Pretarget cues indicated delay‐related response consequences. One indicated that delay would follow the response irrespective of response speed (CERTAIN DELAY), a second that delay would only follow if the response was too slow (CONDITIONAL DELAY), and a third that no delay would follow the response whatever its speed (NO DELAY). Delay levels were 2, 6, or 14 s. Participants also rated their own delay aversion in everyday life.

Results

Individuals with ADHD rated themselves as more delay averse than controls. Significantly greater activation to CERTAIN DELAY cues relative to NO DELAY cues was found in participants with ADHD compared to controls (bilaterally) in amygdala, anterior insula, temporal pole, dorsolateral prefrontal cortex (DLPFC), and ventromedial prefrontal cortex. Amygdala and DLPFC activation strength were strongly and delay‐dose dependently correlated with delay aversion ratings, and statistically mediated the relationship between ADHD status and delay aversion.

Conclusions

When presented with cues predicting impending delay, adolescents with ADHD, relative to controls, displayed a delay‐related increase in activation in amygdala and DLPFC, regions known to be implicated in the processing of aversive events. Future studies should examine the specificity of these effects to delay aversion compared to aversive events in general.     

Cognitive strengths and deficits in schoolchildren with ADHD

BACKGROUND: Few studies provide detailed analyses of the various aspects of the entire cognitive profile of children with ADHD. MATERIAL AND METHODS: Cognitive test data were analysed for 10- to 11-year-old children with (1) ADHD, (2) subthreshold ADHD and (3) milder attention and/or learning problems, and compared with normative data. RESULTS: Thirty-two had ADHD and 10 met the criteria for subthreshold ADHD, prevalence rates of 5.4% and 1.6%, respectively. On a group level, children with ADHD/subthreshold ADHD, and those with milder attention and/or learning problems had almost identical cognitive profiles for the 13 subtests comprising the WISC III, with particularly low results on the arithmetic, coding, information and digit span subtests (ACID profile). When analyzed individually, a complete or incomplete ACID profile (three of four subtests) was equally common in children with ADHD/subthreshold ADHD and in children with milder problems, found in about 1/5. The relative strengths of both groups were in areas demanding logical thinking, reasoning and common sense. CONCLUSION: The specific ACID profile is as common in children with ADHD as in those with minor attention and/or learning problems. The cognitive weaknesses reflected in the ACID profile might play a role as an underlying factor in various developmental disorders.     

Neural and behavioral correlates of expectancy violations in attention-deficit hyperactivity disorder

BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is a prevalent neuropsychiatric disorder in childhood with established problems in cognitive control and associated fronto-striatal circuitry. More recently, fronto-cerebellar circuits have been implicated in this disorder. Both of these circuits are important in predicting the occurrence and timing of behaviorally relevant events and in detecting violations of these predictions. Therefore, we hypothesized that the ability to predict the occurrence of frequent events would be compromised in ADHD, as well as the ability to adapt behavior when expectancy was violated. METHODS: We used rapid, mixed-trial, event-related functional magnetic resonance imaging (fMRI) to examine cognitive and neural processes in two independent samples of children and adolescents with ADHD and matched controls. Subjects performed a variation of a go-no/go task where the predictability of stimulus identity (what) and timing (when) was manipulated. RESULTS: Behaviorally, children and adolescents with ADHD had increased variability in reaction times, and decreased benefit in reaction time when events were predictable. Differences in accuracy between groups were most reliable for temporally unpredictable trials. Functional imaging results from both samples showed that relative to the control children and adolescents, individuals with ADHD had diminished cerebellar activity to violations of stimulus timing and diminished ventral prefrontal and anterior cingulate activity to violations in stimulus timing and identity. CONCLUSIONS: These findings are consistent with the view that disruptive behaviors in inappropriate contexts, a major criterion in diagnosing ADHD, may be related to an impaired ability to predict temporal and contextual cues in the environment, thus hindering the ability to alter behavior when they change. This ability requires intact fronto-cerebellar, as well as fronto-striatal circuitry.     

Attention‐deficit/hyperactivity disorder: Are we medicating for social disadvantage? (Against)

The functional impairments seen in attention deficit hyperactivity disorder (ADHD) are the result of a complex interplay between biological vulnerability and environmental influences. In children with ADHD from social disadvantaged families the latter often appear to predominate. Stimulant medication is the intervention with the largest demonstrable effect size in decreasing the core symptoms of ADHD, irrespective of social context. However, medication alone will not effectively treat common comorbidities, such as oppositional behaviour, anxiety, or learning disabilities. Nor can medication be expected to diminish major family discord or psychosocial adversity. Stimulant medication is one key therapy modality in children with ADHD. Data on prescribing rates do not support the assertion that there is systematic overprescribing of stimulants in Australia. There is, however, a serious problem with access to family support and appropriate services in schools for children with ADHD. Paediatricians have a responsibility to provide evidence-based medical treatment for children with ADHD (i.e. stimulant medication), while advocating across sectors for services to enhance family resilience and function.     

Practitioner Review: Current best practice in the management of adverse events during treatment with ADHD medications in children and adolescents

Background: Medication is an important element of therapeutic strategies for ADHD. While medications for ADHD are generally well‐tolerated, there are common, although less severe, as well as rare but severe adverse events AEs during treatment with ADHD drugs. The aim of this review is to provide evidence‐ and expert‐based guidance concerning the management of (AEs) with medications for ADHD. Methods: For ease of use by practitioners and clinicians, the article is organized in a simple question and answer format regarding the prevalence and management of the most common AEs. Answers were based on empirical evidence from studies (preferably meta‐analyses or systematic reviews) retrieved in PubMed, Ovid, EMBASE and Web of Knowledge through 30 June 2012. When no empirical evidence was available, expert consensus of the members of the European ADHD Guidelines Group is provided. The evidence‐level of the management recommendations was based on the SIGN grading system. Results: The review covers monitoring and management strategies of loss of appetite and growth delay, cardiovascular risks, sleep disturbance, tics, substance misuse/abuse, seizures, suicidal thoughts/behaviours and psychotic symptoms. Conclusion: Most AEs during treatment with drugs for ADHD are manageable and most of the times it is not necessary to stop medication, so that patients with ADHD may continue to benefit from the effectiveness of pharmacological treatment.     

Familial risk analysis of the association between attention-deficit/hyperactivity disorder and psychoactive substance use disorder in female adolescents: a controlled study

Background:  A robust and bi-directional comorbidity between attention-deficit/hyperactivity disorder (ADHD) and psychoactive substance use disorder (PSUD, alcohol or drug abuse, or dependence) has been consistently reported in the literature. However, this literature has been based almost exclusively on male only samples and, therefore, the findings may not generalize to females.
Methods:  First-degree relatives from a large sample of pediatrically and psychiatrically referred girls with (123 probands, 403 relatives) and without ADHD (112 probands, 359 relatives) were comprehensively assessed by blind raters with structured diagnostic interviews. Familial risk analysis examined the risks in first-degree relatives for ADHD and PSUD (alcohol or drug abuse or dependence) after stratifying probands by the presence and absence of these disorders.
Results:  ADHD in the proband significantly increased the risk for ADHD in relatives independently of the comorbidity with PSUD. PSUD in the proband was associated with a significantly increased risk for PSUD in relatives regardless of ADHD status. There was no evidence of co-segregation or non-random mating in the families of probands with ADHD and PSUD.
Conclusions:  Patterns of familial risk analysis suggest that the association between ADHD and PSUD in adolescent females is most consistent with the hypothesis that these disorders are independently transmitted, although the hypothesis of variable expressivity could not be ruled out. These findings are consistent with previously reported patterns of familial associations between ADHD and PSUD found in adolescent males. Longer follow-up periods are needed to more fully clarify the relationship between ADHD and PSUD, as well as provide adequate power for separate analyses of alcohol and drug use.     

The neurobiology of attention deficit/hyperactivity disorder

ADHD is a brain based disorder with structural and functional abnormalities in widespread but specific areas of the brain. The most significant and consistent structural imaging findings include smaller total brain volumes, and reduced volumes in the right frontal lobe, right parietal cortex, caudate nucleus, cerebellar hemispheres, and posterior-inferior lobules of the cerebellar vermis. ADHD involves hypofunction of catecholaminergic circuits, particularly those that project to the prefrontal cortex. A minimum of 18 genes have been reported to be associated with the disorder; among them the DRD4 7-repeat allele has been found associated with a thinner prefrontal and posterior parietal cortex. Epigenetic factors acting during critical periods of prenatal and postnatal development may interact with genetic determinants. Methylphenidate, as well as the catecholaminergic nonstimulant atomoxetine, are effective in improving ADHD symptoms.     

Motor control in children with ADHD and non-affected siblings: deficits most pronounced using the left hand

BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) is strongly influenced by heritability. Identifying heritable vulnerability traits (endophenotypes) that mark a relatively high risk of developing the disorder can contribute to the identification of risk genes. A fruitful area for the search for such endophenotypes may be motor control in children with ADHD, since the disorder is frequently accompanied by motor problems. METHOD: The current study used a large sample of 350 children with ADHD, 195 non-affected siblings and 271 normal controls aged 5-19 years. Children were administered two computerised motor control tasks in which they had to trace a path between two circles (Tracking task) and follow a randomly moving target (Pursuit task). Both tasks were performed with both the right and the left hand. RESULTS: Children with ADHD were less precise and stable than controls. Non-affected siblings also deviated from controls, but only on the Tracking task. Group differences were modulated by the use of the right versus the left hand: no group differences emerged when the right hand was used, yet group differences did emerge when the left hand was used. Performance on both tasks was significantly familial. CONCLUSIONS: Imprecision and instability of movements in children with ADHD and in their non-affected siblings as measured by the Tracking task might be suitable endophenotypic candidates: these deficits are familially present in children having ADHD as well as in their non-affected siblings. Motor performance might be best assessed in children using their left hand, because motor control deficits are most pronounced using the left hand. This might relate to right hemispheric brain pathology in children with ADHD (and possibly in their non-affected siblings) that is related to the control of the left hand and/or relate to differential effects of daily life practice on both hands, which may be smaller on the left hand.     

Variability in post-error behavioral adjustment is associated with functional abnormalities in the temporal cortex in children with ADHD

Background: Error processing is reflected, behaviorally, by slower reaction times (RT) on trials immediately following an error (post‐error). Children with attention‐deficit hyperactivity disorder (ADHD) fail to show RT slowing and demonstrate increased intra‐subject variability (ISV) on post‐error trials. The neural correlates of these behavioral deficits remain unclear. The dorsal anterior cingulate cortex (ACC) and lateral prefrontal cortex (PFC) are key regions implicated in error processing and subsequent behavioral adjustment. We hypothesized that children with ADHD, compared to typically developing (TD) controls, would exhibit reduced PFC activation during post‐error (versus post‐correct inhibition) trials and reduced dACC activation during error (versus correct inhibition) trials. Methods: Using functional Magnetic Resonance Imaging (fMRI) and a Go/No‐Go task, we analyzed the neural correlates of error processing in 13 children with ADHD and 17 TD children. Results: Behaviorally, children with ADHD showed similar RT slowing but increased ISV compared to controls. The post‐error contrast revealed a relative increase in blood‐oxygen‐level dependent (BOLD) signal in the middle/inferior temporal cortex (TempC), the ACC/supplementary motor area (SMA) and the somatosensory/auditory cortex (AudC) in children with ADHD compared to controls. Importantly, in the ADHD group, increased post‐error temporal cortex activity was associated with lower ISV. During error (versus correct inhibition) trials, no between‐group differences were detected. However, in children with ADHD lower ISV was associated with decreased insula and increased precentral gyrus activity. Conclusions: In children with ADHD, post‐error neural activity suggests, first, a shift of attention towards task‐irrelevant stimuli (AudC), and second, a recruitment of compensatory regions that resolve stimulus conflict (TempC) and improve response selection/execution (ACC/SMA). ADHD children with higher temporal cortex activation showed lower ISV, suggesting that functional abnormalities in the compensatory temporal regions contribute to increased variability. Moreover, increased ISV may be related to an over‐sensitivity to negative outcomes during error trials in ADHD (insula correlation).     

Attention deficit disorders: Are we barking up the wrong tree?

Attention deficit disorder (AAD) and attention deficit/hyperactivity disorder (ADHD) are very frequent and protean developmental disorders without a definite biologic marker. This review proposes a framework to understand the enlarged spectrum of its manifestations based on current knowledge of the mechanisms underlying arousal and attention variations during sleep/wake cycle. The neuro-modulation's pivotal role in this process as well as in the fine tuning of synaptic architecture during development must be taken into account when trying to understand the marked fuzziness of the symptoms and the very high prevalence of reported co-morbidities. The series of related interactions includes a cyclic deactivation of the dorso-lateral portion of the prefrontal cortex (DLPFC) during sleep, suspending executive functions, co-occurring with rhythmic periods of decreased noradrenergic tonus. A protracted unbalance in modulation, with catecholaminergic relative deficiency, could explain less-than-optimum waking DLPFC activation and the most important manifestations of ADD. Beside the well documented dopaminergic effects of stimulant medication used in ADD and ADHD, a more important role must be assigned to noradrenaline (NA). At this light hyperactivity and impulsivity are less important dimensions. Rather, an attention deficit spectrum disorder should probably be regarded as a complication of a core defect in prefrontal cortex dependent inhibitory control, underlying inattention.     

Childhood attention-deficit hyperactivity disorder as an extreme of a continuous trait: a quantitative genetic study of 8,500 twin pairs

Background: Although the clinical utility of categorically defined attention‐deficit hyperactivity disorder (ADHD) is well established, there is also strong evidence supporting the notion of ADHD as an extreme of a continuous trait. Nevertheless, the question of whether the etiology is the same for different levels of DSM–IV ADHD symptoms remains to be investigated. The aim of this study was to assess genetic links between the extreme and the subthreshold range of ADHD symptoms. Method: Parents of all Swedish 9‐ and 12‐year‐old twins born between 1992 and 2000 were interviewed for DSM–IV ADHD symptoms and associated conditions. Two validated cutoff values were used for screening and assigning research diagnoses. Response rate was 80%. Twin methods were applied to investigate the extent to which ADHD is etiologically distinct from subthreshold variations in ADHD symptoms. Results: Extremes analyses indicated a strong genetic link between the extreme and the subthreshold variation, with almost identical group heritability estimates around .60 for the diagnostic (prevalence 1.78%) and screening (prevalence 9.75%) criteria of ADHD. Conclusion: A strong genetic link between the extreme and the subthreshold variation of DSM–IV based assessments of ADHD symptoms was found. The data suggest that ADHD is best viewed as the quantitative extreme of genetic and environmental factors operating dimensionally throughout the distribution of ADHD symptoms, indicating that the same etiologic factors are involved in the full range of symptoms of inattention, hyperactivity and impulsivity.     

The Association of Socioeconomic Vulnerability and Race and Ethnicity With Disease Burden Among Children in a Statewide Medicaid Population

ObjectiveIndividuals enrolled in Medicaid have disproportionately worse health outcomes due to challenges related to Social Determinants of Health. We aim to examine the prevalence of 3 childhood conditions (asthma, type 2 diabetes, and attention deficit hyperactivity disorder [ADHD]) in children within the Texas Medicaid system. In order to recognize the layers of vulnerability, we examine prevalence at the intersection of socioeconomic status with race and ethnicity within this economically challenged population.MethodsChildren ages 0 to 17 were identified from claims and encounter data for all children enrolled in Texas Medicaid in 2017 for at least 6 months. All children were placed into one of 5 quintiles based on their census tract socioeconomic vulnerability. The Rate Ratio statistical test was employed to identify the statistical significance of the disparity in health outcomes related to higher neighborhood vulnerability within each racial or ethnic group.ResultsAsthma for each race and ethnicity group was significantly more prevalent in the higher vulnerability census tracts. Increased vulnerability related to significant increase in type 2 diabetes for Hispanic children, but not for other groups. Diagnosed ADHD prevalence was significantly higher in less vulnerable non-Hispanic white children compared to more vulnerable.ConclusionsThis study found that even among children who receive Medicaid and are thus economically disadvantaged, socioeconomic vulnerability applies an additional burden within racial and ethnic groups to produce disparities in health-related burden. However, the trend of the relationship varied by race and ethnicity group and health condition.     

Sintomatología del trastorno por déficit de atención con hiperactividad y su relación con el maltrato infantil: predictor y consecuencia

The current literature increasingly associates the presence of symptoms of ADHD in both physical and psychological and sexual child abuse. This implies the need for greater accuracy in the differential diagnosis, as until a few years ago, post-traumatic stress disorder was considered the reference symptoms for this type of case. Thus, it is necessary to define and conceptualize an increasingly broad and detailed world of sequels and consequences, where ADHD may be related to the psychological damage suffered by child abuse. Furthermore, the particular vulnerability of children with ADHD can, in turn, become a factor of risk that needs to be considered by the professionals who care for this type of patient.     

ADHD- and medication-related brain activation effects in concordantly affected parent-child dyads with ADHD

BACKGROUND: Several studies have documented fronto-striatal dysfunction in children and adolescents with attention deficit/hyperactivity disorder (ADHD) using response inhibition tasks. Our objective was to examine functional brain abnormalities among youths and adults with ADHD and to examine the relations between these neurobiological abnormalities and response to stimulant medication. METHOD: A group of concordantly diagnosed ADHD parent-child dyads was compared to a matched sample of normal parent-child dyads. In addition, ADHD dyads were administered double-blind methylphenidate and placebo in a counterbalanced fashion over two consecutive days of testing. Frontostriatal function was measured using functional magnetic resonance imaging (fMRI) during performance of a go/no-go task. RESULTS: Youths and adults with ADHD showed attenuated activity in fronto-striatal regions. In addition, adults with ADHD appeared to activate non-fronto-striatal regions more than normals. A stimulant medication trial showed that among youths, stimulant medication increased activation in fronto-striatal and cerebellar regions. In adults with ADHD, increases in activation were observed in the striatum and cerebellum, but not in prefrontal regions. CONCLUSIONS: This study extends findings of fronto-striatal dysfunction to adults with ADHD and highlights the importance of frontostriatal and frontocerebellar circuitry in this disorder, providing evidence of an endophenotype for examining the genetics of ADHD.     

注意缺陷多动性障碍儿童冲动的自我调控:Go/NoGo任务的ERPs P3分析

目的 基于行动和抑制过程研究注意缺陷多动性障碍儿童的冲动调控缺陷,进行Go/NoGo任务的事件相关电位(ERPs)P3成分的分析.方法 选择15名冲动性高的ADHD 儿童和15名正常对照组儿童,在ERPs实验中采用Go/NoGo刺激反应模式.Go和NoGo刺激出现的机率相等(各50%).结果 ①与正常儿童相比,高冲动儿童在作出的正确反应中,Go反应时较慢,而在作出的错误反应中,NoGo反应时较快,反应的正确率低.②P3波幅在病例组和对照组中都有Go-P3>NoGo-P3的倾向,尤其在ADHD的CPz和Pz点上差异有统计学意义,表现出顶中央区到顶区最大的趋势,而在额区最小.ADHD儿童的NoGo-P3波幅较小,尤其在FCz和Cz点显著,在左半球有比对照组小的倾向.③ADHD 儿童的NoGo-P3比正常儿童小,在FCz更显著.④脑地形图显示冲动的ADHD儿童右额叶的激活比正常儿童弱.结论 ADHD儿童行动的效率低,对行为的调控能力受限.Go/NoGo-P3反映行动和注意加工,左顶叶到中央区参与行动和注意加工过程.ADHD儿童顶叶皮层和右额叶功能减弱.     

The neural correlates of attention deficit hyperactivity disorder: an ALE meta-analysis

BACKGROUND: Attention deficit/hyperactivity disorder (ADHD) is one of the most prevalent and commonly studied forms of psychopathology in children and adolescents. Causal models of ADHD have long implicated dysfunction in fronto-striatal and frontal-parietal networks supporting executive function, a hypothesis that can now be examined systematically using functional neuroimaging. The present work provides an objective, unbiased statistically-based meta-analysis of published functional neuroimaging studies of ADHD. METHODS: A recently developed voxel-wise quantitative meta-analytic technique known as activation likelihood estimation (ALE) was applied to 16 neuroimaging studies examining and contrasting patterns of neural activity in patients with ADHD and healthy controls. Voxel-wise results are reported using a statistical threshold of p < .05, corrected. Given the large number of studies examining response inhibition, additional meta-analyses focusing specifically on group differences in the neural correlates of inhibition were included. RESULTS: Across studies, significant patterns of frontal hypoactivity were detected in patients with ADHD, affecting anterior cingulate, dorsolateral prefrontal, and inferior prefrontal cortices, as well as related regions including basal ganglia, thalamus, and portions of parietal cortex. When focusing on studies of response inhibition alone, a more limited set of group differences were observed, including inferior prefrontal cortex, medial wall regions, and the precentral gyrus. In contrast, analyses focusing on studies of constructs other than response inhibition revealed a more extensive pattern of hypofunction in patients with ADHD than those of response inhibition. CONCLUSIONS: To date, the most consistent findings in the neuroimaging literature of ADHD are deficits in neural activity within fronto-striatal and fronto-parietal circuits. The distributed nature of these results fails to support models emphasizing dysfunction in any one frontal sub-region. While our findings are suggestive of the primacy of deficits in frontal-based neural circuitry underlying ADHD, we discuss potential biases in the literature that need to be addressed before such a conclusion can be fully embraced.     

Assessment and treatment of attention deficit hyperactivity disorder in children with comorbid psychiatric illness

PURPOSE OF REVIEW: Attention deficit hyperactivity disorder (ADHD) frequently occurs with a wide variety of comorbid psychiatric disorders such as conduct disorder, depression, mania, anxiety, and learning disabilities. Because the vast majority of children with ADHD are treated in primary care settings, it is important that primary medical doctors be proficient in the diagnosis and initial treatment of children with ADHD and its commonly occurring comorbid disorders. ADHD research is beginning to focus on the treatment of these comorbidly ill children. This review will summarize the recent findings from the psychiatric literature in an attempt to provide the clinician with some initial diagnostic and treatment guidelines for ADHD and its comorbidities. RECENT FINDINGS: The NIMH Multimodal Treatment Study of ADHD found that children with other disruptive behavior disorders plus ADHD respond well to stimulant medications, with behavioral interventions reducing academic and social impairment. Children with anxiety and ADHD are very responsive across multiple dimensions to behavioral and pharmacological ADHD treatments. Much less is known about the impact of depression on ADHD, and significant debate exists surrounding the identification and treatment of bipolar disorder in children with ADHD. Children with learning disabilities respond well to stimulants but often require additional educational supports. New findings suggest that treating ADHD may prevent the development of future psychiatric disorders. SUMMARY: The presence of comorbid illness is associated with significant additional morbidity and complicates the diagnosis, treatment, and prognosis of ADHD. Therefore, it is important to identify and treat any comorbid psychiatric conditions in a child with ADHD.     

An epidemiological study of ADHD symptoms among young persons and the relationship with cigarette smoking, alcohol consumption and illicit drug use

Background: This study investigates the relationship between attention deficit hyperactivity disorder (ADHD) symptoms and cigarette smoking, alcohol use and illicit drug use. Method: The participants were 10,987 pupils in the final three years of their compulsory education in Iceland (ages 14–16 years). The participants completed questionnaires in class relating to anxiety, depression and antiestablishment attitudes, ADHD symptoms, smoking, alcohol consumption and illicit drug use. Results: Of the total sample, 5.4% met screening criteria for ADHD. Smoking, alcohol and illicit drug use were significantly related to ADHD symptoms. In addition, the number of different illicit drugs consumed was significantly higher among the ADHD symptomatic than the nonsymptomatic participants, including the illicit use of sedatives. The main distinguishing illicit drug substances were lysergic acid diethylamide (odds ratio or OR = 8.0), cocaine (OR = 7.5), mushrooms (OR = 7.1) and amphetamines (OR = 6.5). Logistic multiple regressions showed that after controlling for gender and school grade, ADHD symptoms predicted smoking, alcohol use and illicit drug use independent of anxiety, depression and antiestablishment attitudes. In addition, poly‐substance use was linearly and incrementally related to ADHD symptoms with a large effect size. Conclusions: The findings underscore the vulnerability of young persons with ADHD symptoms to smoking, alcohol and illicit drug use, possibly as a means of self‐medication, and emphasize a need for early identification and treatment to reduce the risk of escalation.