Attention-deficit/hyperactivity disorder and comorbidity

A review of association and linkage studies for genetical analyses of learning disorders

Learning disorders (LD) commonly comprise of a heterogeneous group of disorders manifested by unexpected problems in some children's experiences in the academic performance arena. These problems especially comprise of a variety of disorders which may be subclassified to attention-deficit hyperactivity disorder (ADHD), reading disability (RD), specific language impairment (SLI), speech-sound disorder (SSD), and dyspraxia. The aim of this review is to summarize the current molecular studies and some of the most exciting recent developments in molecular genetic research on LD. The findings for the association and linkage of LD with candidate genes will help to set the research agendas for future studies to follow.

Psychiatric features and parenting stress profiles of subtypes of attention-deficit/hyperactivity disorder: results from a clinically referred Taiwanese sample

OBJECTIVE

This study attempts to evaluate whether there are attention deficit/ hyperactivity disorder (ADHD) subtype differences regarding psychiatric features, comorbidity pattern and parenting stress profiles in an Asian population.

METHODS

A total of 182 ADHD children and their primary caretakers recruited from a university-affiliated hospital were surveyed. Subjects were two groups of preadolescent (6 to 12 years old) ADHD children: children with ADHD-inattentive subtype (n=58) and ADHD-combined subtype (n=124). Various information was collected and compared, including the child's characteristics (current age, gender, number of family members, age at ADHD diagnosis, duration of pharmaceutical intervention, psychiatric comorbidities, and intelligence quotient); the primary caretaker's characteristics, and profiles obtained with the Parenting Stress Index (PSI).

RESULTS

Group comparison showed that these two subtypes were statistically distinguishable from each other in total scores on the PSI, four subscale scores on the PSI, the child's age at diagnosis, and comorbidity profiles (all p<.05). Parents of children of the combined subtype experienced higher parenting stress and felt their children displayed qualities that made it difficult for them to fulfill their parenting roles. School failure (p=.001) and anxiety disorders (p=.022) were significantly more prevalent in the inattentive subtype children, while oppositional defiant disorder was significantly more present in the combined subtype children (p=.000).

CONCLUSIONS

Our findings supported the cross-cultural equivalence of the nosological distinction in ADHD subtypes. The need for specific clinical intervention according to the subtype difference was stressed.

Differentiating major depressive disorder in youths with attention deficit hyperactivity disorder

BACKGROUND

Youths with attention deficit hyperactivity disorders (ADHD) frequently have comorbid major depressive disorders (MDD) sharing overlapping symptoms. Our objective was to examine which depressive symptoms best discriminate MDD among youths with ADHD.

METHODS

One-hundred-eleven youths with ADHD (5.2-17.8 years old) and their parents completed interviews with the K-SADS-PL and respective versions of the child or the parent Mood and Feelings Questionnaire (MFQ-C, MFQ-P). Controlling for group differences, logistic regression was used to calculate odds ratios reflecting the accuracy with which various depressive symptoms on the MFQ-C or MFQ-P discriminated MDD. Stepwise logistic regression then identified depressive symptoms that best discriminated the groups with and without MDD, using cross-validated misclassification rate as the criterion.

RESULTS

Symptoms that discriminated youths with MDD (n=18) from those without MDD (n=93) were 4 of 6 mood/anhedonia symptoms, all 14 depressed cognition symptoms, and only 3 of 11 physical/vegetative symptoms. Mild irritability, miserable/unhappy moods, and symptoms related to sleep, appetite, energy levels and concentration did not discriminate MDD. A stepwise logistic regression correctly classified 89% of the comorbid MDD subjects, with only age, anhedonia at school, thoughts about killing self, thoughts that bad things would happen, and talking more slowly remaining in the final model.

LIMITATIONS

Results of this study may not generalize to community samples because subjects were drawn largely from a university-based outpatient psychiatric clinic.

CONCLUSIONS

These findings stress the importance of social withdrawal, anhedonia, depressive cognitions, suicidal thoughts, and psychomotor retardation when trying to identify MDD among ADHD youths.

Practice parameter for the assessment and treatment of children and adolescents with attention-deficit/hyperactivity disorder

This practice parameter describes the assessment and treatment of children and adolescents with attention-deficit/hyperactivity disorder (ADHD) based on the current scientific evidence and clinical consensus of experts in the field. This parameter discusses the clinical evaluation for ADHD, comorbid conditions associated with ADHD, research on the etiology of the disorder, and psychopharmacological and psychosocial interventions for ADHD.

Treating common psychiatric disorders associated with attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) often occurs along with other psychiatric disorders, with estimated comorbidity rates of 50--90%. Comorbidity greatly influences presentation, diagnosis and prognosis, complicates treatment and significantly increases the morbidity and disease burden of ADHD. Commonly co-occurring psychiatric disorders are disruptive behavior disorder, anxiety, depression, bipolar disorder and substance use disorders. This article provides a brief review of effective strategies for treating the most common psychiatric disorders associated with ADHD. This paper also discusses knowledge gaps in the understanding of treatment of comorbid disorders associated with ADHD, and directions for future research.

Pharmacotherapy of attention-deficit/hyperactivity disorder: nonstimulant medication approaches

Attention-deficit/hyperactivity disorder (ADHD) is one of the most common chronic health conditions and mental disorders affecting school-aged children. Prevalence with a conservative estimate is reported to be 3-5% of this population. Boys are approximately three-times more likely to be diagnosed than girls. The diagnosis refers to a family of related chronic neurobiological disorders that interfere with an individual's capacity to regulate activity level, inhibit behavior and attend to tasks in developmentally appropriate ways. Signs and symptoms of ADHD are typically present during the preschool period or in the early elementary school years, and the diagnosis requires that difficulties were present at or before age 7 years and create problems or impairment in at least two areas of the child's life (e.g., at school, on the playground, on the bus, at home or socially with peers). Stimulants are the first-line medication in the psychopharmacological treatment of ADHD. Between 10 and 30% of those affected with ADHD may not respond to stimulants or may not be able to tolerate associated side effects, such as appetite suppression, sleep disturbance, mood difficulties or exacerbation of comorbid tic disorders. In such instances, or when families are unwilling to consider a stimulant, nonstimulant medications may be appealing. Several nonstimulant medications that affect noradrenergic and/or dopaminergic pathways have demonstrated efficacy in the treatment of ADHD, although effect sizes are comparable with methylphenidate, fewer data have accumulated regarding the safety profile of nonstimulants in general. This review focuses on etiology, assessment and treatment of ADHD, in particular alternative treatment approaches with various nonstimulant agents, especially atomoxetine.

Attention Deficit Hyperactivity Disorder Across the Lifespan: The Child, Adolescent, and Adult

Management of a child, adolescent, college student, or adult with ADD/ADHD (ADHD) is reviewed with emphasis on pharmacologic approaches in the adult. Psychological treatment includes psychotherapy, cognitive-behavior therapy, support groups, parent training, biofeedback, meditation, and social skills training. Medications are reviewed that research has revealed can improve the core symptomatology of a child or adolescent with ADHD. These medications include stimulants (psychostimulants), antidepressants, alpha-2 agonists, and a norepinephrine reuptake inhibitor. Psychopharmacology approved and/or used in pediatric patients are also used in adults with ADHD, though most are not officially FDA-approved. It is emphasized that ADHD management should include a multi-modal approach, involving appropriate educational interventions, appropriate psychological management of the patient of any age, and judicious use of medications. Such an approach is recommended to benefit those with ADHD achieve their maximum potential across the human life span.

Latent class analysis shows strong heritability of the child behavior checklist-juvenile bipolar phenotype

BACKGROUND

The Child Behavior Checklist (CBCL) has been used to provide a quantitative description of childhood bipolar disorder (BPAD). Many have reported that children in the clinical range on the Attention Problems (AP), Aggressive Behavior (AGG), and Anxious-Depressed (A/D) syndromes simultaneously are more likely to meet the criteria for childhood BPAD. The purpose of this study was to determine if Latent Class Analysis (LCA) could identify heritable phenotypes representing the CBCL-Juvenile Bipolar (CBCL-JBD) profile and whether this phenotype demonstrates increased frequency of suicidal endorsement.

METHODS

The CBCL data were received by survey of mothers of twins in two large twin samples, the Netherlands Twin Registry. The setting for the study was the general community twin sample. Participants included 6246 10-year-old Dutch twins from the Netherlands Twin Registry. The main outcome measure consisted of the LCA on the items comprising the AP, AGG, and A/D subscales and means from the suicidal items #18 and #91 within classes.

RESULTS

A 7 class model fit best for girls and an 8 class fit best for boys. The most common class for boys or girls was one with no symptoms. The CBCL-JBD phenotype was the least common--about 4%-5% of the boys and girls. This class was the only one that had significant elevations on the suicidal items of the CBCL. Gender differences were present across latent classes with girls showing no aggression without the CBCL-JBD phenotype and rarely showing attention problems in isolation. Evidence of high heritability of these latent classes was found with odds ratios.

CONCLUSIONS

In a general population sample, LCA identifies a CBCL-JBD phenotype latent class that is associated with high rates of suicidality, is highly heritable, and speaks to the comorbidity between attention problems, aggressive behavior, and anxious/depression in children.

ADHD with comorbid anxiety: a review of the current literature

OBJECTIVE/METHOD

ADHD is often comorbid with anxiety disorders, with rates approaching 25% in many samples. This current review's goal is to examine the literature on ADHD with comorbid anxiety from 1998 to the present.

RESULTS

Recent studies indicate that anxiety in ADHD may a) partially inhibit the impulsivity and response inhibition deficits, b) make working memory deficits worse, and c) may be qualitatively different from more phobic types of anxiety seen in pure anxiety samples. In examining subtypes of ADHD, measures of sluggish cognitive tempo show strong correlations with anxiety measures. Insights into the nature of the comorbidity between ADHD and anxiety may be gained by examining the possible comorbidity between Obsessive Compulsive Disorder and ADHD, shared risk factors for ADHD and anxiety, and the current pathogenic models of ADHD.

CONCLUSION

The article concludes with a synthesis of the above work, along with directions for future research.

ADHD: new pharmacological treatments on the horizon

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurobehavioral disorder affecting school-age children. In many cases, symptoms persist into adolescence and adulthood, causing significant lifelong impairments in academic, career, and social functioning. The stimulants methylphenidate and amphetamines have been used for decades as first-line therapy for the treatment of ADHD. Short-acting stimulant formulations control symptoms only for a few hours, creating the need for multiple daily doses of the medication. For school-age children, this necessitates administering medication during school hours, creating the potential for embarrassment and noncompliance. To offset these problems, longer acting stimulant formulations have been developed. Long-acting medications often control symptoms for up to 8 hours with only one daily dose of the medication, eliminating the need for in-school administration. Some long-acting stimulants are designed to control symptoms for up to 10 to 12 hours. Although stimulants are effective in most cases, some children are unable to tolerate these medications. Nonstimulant options are available for the treatment of ADHD and include atomoxetine, alpha-adrenergic agents, and antidepressants. Of these, atomoxetine is the only medication approved to treat ADHD. In spite of the number of medications available for the management of ADHD, treatment options with greater flexibility and reduced side effects are still desirable. A transdermal methylphenidate patch has recently been approved, and advances to existing stimulants currently under development include an amphetamine prodrug and a longer acting formulation of amphetamine. In addition, a number of nonstimulant entities, including guanfacine and modafinil, are under development for the treatment of ADHD.

New methylphenidate formulations for the treatment of attention-deficit/hyperactivity disorder

dl-Methylphenidate (MPH) remains the most widely used pharmacological agent in the treatment of attention-deficit/hyperactivity disorder (ADHD). The predominantly dopaminergic mechanism of the psychostimulant actions has become more clearly defined. Neuroimaging and genetic studies are revealing the underlying neuropathology in ADHD. Novel extended-release (ER) MPH formulations now offer drug delivery options to overcome both the short-term actions of immediate-release (IR) MPH and the acute tolerance associated with the first-generation ER-MPH products. These novel MPH products apply proprietary technologies such as OROS (Alza), Diffucaps (Eurand) and SODAS (Elan) to offer both the convenience of once-a-day administration and absorption profiles resembling, to varying degrees, the standard multiple dose schedules of IR-MPH. The pharmacodynamics of the separate MPH enantiomers is in the process of further neuropharmacological characterisation. It is well established that dl-MPH undergoes marked stereoselective metabolism. Although l-MPH exhibits only minimal oral absorption, it may preferentially penetrate the brain, and interacts with ethanol to form the metabolite ethylphenidate. The newly approved resolved enantiomer product d-MPH is now available in an IR formulation, and when administered at one-half the dose to that of the racemate, is purported to produce a longer duration of clinical effect, despite essentially identical pharmacokinetics. A long-acting formulation of d-MPH, which employs the SODAS technology, is in the advanced stages of clinical development.

MAOA promoter polymorphism and attention deficit hyperactivity disorder (ADHD) in indian children

Attention deficit hyperactivity disorder (ADHD) is a highly disabling, early onset childhood neurobehavioral disorder with a higher occurrence in boys as compared to girls. Pharmacological and molecular genetic studies have revealed the influence of dopaminergic and serotonergic systems in the etiology of the disorder. Monoamine oxidase A (MAOA) is a mitochondrial enzyme that regulates the dopaminergic signals in the pre-synaptic region. Polymorphism in the promoter region of the MAOA gene, which comprises of 30 bp repeats with repeat number varying between 2.5, 3.5, 4.5, and 5.5, has been shown to be associated with various neurobehavioral disorders including ADHD. This is the first study on Indian ADHD cases to validate an association between transmission of MAOA promoter polymorphism and risk of ADHD. We have analyzed the MAOA promoter polymorphism in a group of ADHD probands, their parents and ethnically matched controls by UNPHASED. Our findings indicate significant difference in the frequency of 3.5 repeat allele (P = 0.02) between cases and controls and preferential transmission of the short allele (3.5 repeat) from mothers to male ADHD probands (P = 0.005). We conclude that the short 3.5 repeat allele of the MAOA-u VNTR is probably associated with ADHD in our population and could be the reason for making boys prone to ADHD as compared to girls.

The Psychopharmacologic Treatment of Violent Youth

Aggressive violence has been described as the greatest problem and the most frequent reason for referrals in child and adolescent psychiatry. In this country we have only partially emerged from an epidemic of violence that was really an epidemic of youth violence. Thus it is hardly surprising that psychiatrists are being asked more and more frequently whether psychiatric medications might help to diminish the toll from this behavioral plague. Medications are useful and appropriate for only a small minority of the people who commit serious violence. Even when they are indicated, they can never be the sole treatment modality, but should be supplemented by psychological and social therapies. When the violence is a byproduct or symptom of an underlying mental illness, treating that illness is generally the most effective method of preventing future violence on a long-term basis. However, most violence is not committed by those who are mentally ill, and most of the mentally ill never commit a serious act of violence. That is why many attempts have been made to discover whether there are drugs that diminish the symptom, violence, even when there is no underlying mental illness for which drugs would normally be prescribed. In fact there are several, and their indications and use are reviewed here. Different principles govern the acute short-term emergency treatment of a violent crisis and the long-term treatment of those who are chronically and repetitively violent, and these differences are also summarized here.

Transtorno do déficit de atenção e hiperatividade (TDAH): aspectos relacionados à comorbidade com distúrbios da atividade motora

A presente revisão aborda aspectos fisiopatológicos e clínicos referentes ao Transtorno do Déficit de Atenção com Hiperatividade (TDAH), em especial aqueles que concernem à associação desse transtorno com o Distúrbio do Desenvolvimento da Coordenação (DDC). Utilizou-se a base de dados Medline para levantamento de artigos indexados a partir de 1965 até 2004. Aos artigos selecionados dessa forma, outros foram obtidos pela relevância atribuída a eles nas fontes iniciais. A pré-disposição hereditária desse transtorno é indiscutível, bem como a presença da disfunção nora-drenégica e dopaminérgica no córtex pré-frontal e suas conexões. Apesar desse conhecimento, o diagnóstico da condição se baseia em dados clínicos. As associações mórbidas ocorrem em cerca de metade dos indivíduos, sendo as principais comorbidades de natureza psiquiátrica. A presença de uma comorbidade pode modificar a terapêutica e o prognóstico. O Distúrbio do Desenvolvimento da Coordenação, condição também de diagnostico clínico, confere pior prognóstico às crianças que partilham ambos os quadros. Recomenda-se que uma busca ativa de condições associadas seja realizada em cada criança diagnosticada como portadora de TDAH.

Neurofeedback: An Alternative and Efficacious Treatment for Attention Deficit Hyperactivity Disorder

Current research has shown that neurofeedback, or EEG biofeedback as it is sometimes called, is a viable alternative treatment for Attention Deficit Hyperactivity Disorder (ADHD). The aim of this article is to illustrate current treatment modalities(s), compare them to neurofeedback, and present the benefits of utilizing this method of treatment to control and potentially alleviate the symptoms of ADHD. In addition, this article examines the prevalence rates and possible etiology of ADHD, the factors associated with ADHD and brain dysfunction, the current pharmacological treatments of ADHD, Ritalin, and the potential risks and side effects. Behavior modification and cognitive behavioral treatment for ADHD is discussed as well. Lastly, a brief history of the study of neurofeedback, treatment successes and clinical benefits, comparisons to medication, and limitations are presented.

What is attention-deficit hyperactivity disorder (ADHD)?

Attention-deficit hyperactivity disorder (ADHD) is described as the most common neurobehavioral condition of childhood. We raise the concern that ADHD is not a disease per se but rather a group of symptoms representing a final common behavioral pathway for a gamut of emotional, psychological, and/or learning problems. Increasing numbers of children, especially boys, are diagnosed with ADHD and treated with stimulant medications according to a simplified approach. Methodical review of the literature, however, raised concerning issues. "Core" ADHD symptoms of inattentiveness, hyperactivity and impulsivity are not unique to ADHD. Rates of "comorbid" psychiatric and learning problems, including depression and anxiety, range from 12 to 60%, with significant symptom overlap with ADHD, difficulties in diagnosis, and evidence-based treatment methods that do not include stimulant medications. No neuropsychologic test result is pathognomic for ADHD, and structural and functional neuroimaging studies have not identified a unique etiology for ADHD. No genetic marker has been consistently identified, and heritability studies are confounded by familial environmental factors. The validity of the Conners' Rating Scale-Revised has been seriously questioned, and parent and teacher "ratings" of school children are frequently discrepant, suggesting that use of subjective informant data via scale or interview does not form an objective basis for diagnosis of ADHD. Empiric diagnostic trials of stimulant medication that produce a behavioral response have been shown not to distinguish between children with and without "ADHD." In summary, the working dogma that ADHD is a disease or neurobehavioral condition does not at this time hold up to scrutiny of evidence. Thorough evaluation of symptomatic children should be individualized, and include assessment of educational, psychologic, psychiatric, and family needs.

Symptoms of inattention and hyperactivity in children with habitual snoring: evidence from a community-based study in Istanbul

BACKGROUND

Neurobehavioural symptoms of inattention and hyperactivity are common in children with sleep-disordered breathing (SDB). Prevalence rates of habitual snoring and attention deficit hyperactivity disorder (ADHD) are very similar and both have a substantial negative effect on children's behavioural health.

OBJECTIVE

We examined the differences for subjective attentional and hyperactivity measures reported by parents and teachers among primary school children with habitual snoring and age- and sex-matched controls in a community-based case-control study in Istanbul. Methods In 2002, a survey was carried out to determine the prevalence of snoring in 2147 primary school children. After one year, in 2003, 151 children with habitual snoring and 302 controls from this survey were studied with parental SDB questionnaire, Conners' Parent (Conners-P) and Teacher Scales, and an inattention hyperactivity scale (IHS). Exclusion criteria included history of ADHD diagnosis, controls who started to snore and habitual snorers (HS) who no longer snored in this follow-up study.

RESULTS

Ninety-six HS and 190 control subjects (mean age: 9.4 +/- 1.3) were evaluated. HS had significantly more symptoms of hyperactivity (Conners-ADHD index) (P: 0.033), attentional (P: 0.019), and conduct and oppositional defiant in subscales (P: 0.001) of Conners-P and IHS-Parents. A pooled score of Conners-P ADHD Index > 60 and IHS-Parent score > 1.25 showed considerable difference in HS when compared with controls (5.1% vs. 1.4%) (P < 0.0001). Daytime hyperactivity and excessive daytime sleepiness reported by parents correlated with scores of Conners-P and IHS-P (P < 0.01). Teachers' observations showed significant correlations with learning disability and the level of academic performance in HS (P < 0.01). Other behavioural parameters related to SDB were not significantly correlated with teachers' ADHD ratings in HS.

CONCLUSION

Increased rates of moderate hyperactivity as well as conduct and oppositional defiant symptoms in HS reported by the parents might reflect a negative impact on overall neurobehavioural health. The teachers' scores yielded no significant results among HS and controls. This may be caused by the limitation due to shared method variance. The negative effect of crowded classes on teachers' evaluations must be also taken into consideration. After exclusion of a diagnosis of ADHD in children presenting with hyperactivity and inattention, children with habitual snoring with prominent scores of behavioural measures should be considered as candidates for further assessment by a sleep specialist.

The CBCL as a screen for psychiatric comorbidity in paediatric patients with ADHD

AIMS

To examine the informativeness of the Child Behavior Checklist (CBCL) as a screening tool to identify comorbid and non-comorbid cases of attention deficit hyperactivity disorder (ADHD) in a paediatrically referred population. It was hypothesised that specific scales of the CBCL would help identify specific comorbidities within ADHD cases in the primary care setting.

METHODS

The sample consisted of children and adolescents 6-17 years old of both genders with ADHD (n = 121). A receiver operating curve (ROC) approach was used to determine which CBCL scales best differentiated between ADHD cases with and without its comorbidities with conduct, anxiety, and mood disorders.

RESULTS

ROC analysis showed that the CBCL Delinquent Behavior and Aggressive Behavior scales predicted the structured interview derived diagnoses of conduct and bipolar disorder, the Anxious/Depressed and Aggressive Behavior scales predicted major depression, and the Anxious/Depressed and Attention problems scales predicted anxiety disorders.

CONCLUSIONS

These results extend to a paediatrically referred population with previously reported findings in psychiatric samples documenting good convergence between structured interview diagnoses and syndrome congruent CBCL scales. These findings support the utility of the CBCL as a screening tool for the identification of psychiatric comorbidity in ADHD youth in the primary care setting.

Safety, efficacy and extended duration of action of mixed amphetamine salts extended-release capsules for the treatment of ADHD

Stimulant medications have proven to be effective in reducing the core symptoms of hyperactivity, impulsivity and inattention and are considered the first line of therapy for patients with attention-deficit/hyperactivity disorder (ADHD). Mixed amphetamine salts extended-release capsules (MAS XR; Adderall XR, Shire Pharmaceuticals Group) include immediate-release pellets of mixed amphetamine salts that release the first half of the dose upon ingestion and delayed-release pellets that begin to release active drug approximately 4 h later. The MAS XR capsule contains the same 3:1 ratio of dextroamphetamine to levoamphetamine as do mixed amphetamine salts immediate-release tablets (MAS IR; Adderall), Shire Pharmaceuticals Group), and the bioavailability and pharmacokinetic profiles of MAS XR 20 mg are comparable to those with MAS IR 10 mg b.i.d. MAS XR has a rapid onset of action--within 1.5 h--and provides 12 h coverage. The efficacy, safety and extended duration of action of MAS XR have been established through clinical studies in school-age children, adolescents and adults.

A review of the economic burden of ADHD

Attention-deficit hyperactivity disorder (ADHD) is a common disorder that is associated with broad functional impairment among both children and adults. The purpose of this paper is to review and summarize available literature on the economic costs of ADHD, as well as potential economic benefits of treating this condition. A literature search was performed using MEDLINE to identify all published articles on the economic implications of ADHD, and authors were contacted to locate conference abstracts and articles in press that were not yet indexed. In total, 22 relevant items were located including published original studies, economic review articles, conference presentations, and reports available on the Internet. All costs were updated and presented in terms of year 2004 US dollars. A growing body of literature, primarily published in the United States, has demonstrated that ADHD places a substantial economic burden on patients, families, and third-party payers. Results of the medical cost studies consistently indicated that children with ADHD had higher annual medical costs than either matched controls (difference ranged from $503 to $1,343) or non-matched controls (difference ranged from $207 to $1,560) without ADHD. Two studies of adult samples found similar results, with significantly higher annual medical costs among adults with ADHD (ranging from $4,929 to $5,651) than among matched controls (ranging from $1,473 to $2,771). A limited number of studies have examined other economic implications of ADHD including costs to families; costs of criminality among individuals with ADHD; costs related to common psychiatric and medical comorbidities of ADHD; indirect costs associated with work loss among adults with ADHD; and costs of accidents among individuals with ADHD. Treatment cost-effectiveness studies have primarily focused on methylphenidate, which is a cost-effective treatment option with cost-effectiveness ratios ranging from $15,509 to $27,766 per quality-adjusted life year (QALY) gained. As new treatments are introduced it will be important to evaluate their cost-effectiveness to provide an indication of their potential value to clinicians, patients, families, and third-party payers.

The dopamine transporter and attention-deficit/hyperactivity disorder

The high incidence of attention-deficit/hyperactivity disorder (ADHD) and escalating use of ADHD medications present a compelling case for clarifying the pathophysiology of, and developing laboratory or radiologic tests for, ADHD. Currently, the majority of specific genes implicated in ADHD encode components of catecholamine signaling systems. Of these, the dopamine transporter (DAT) is a principal target of the most widely used antihyperactivity medications (amphetamine and methylphenidate); the DAT gene is associated with ADHD, and some studies have detected abnormal levels of the DAT in brain striatum of ADHD subjects. Medications for ADHD interfere with dopamine transport by brain-region- and drug-specific mechanisms, indirectly activating dopamine- and possibly norepinephrine-receptor subtypes that are implicated in enhancing attention and experiential salience. The most commonly used DAT-selective ADHD medications raise extracellular dopamine levels in DAT-rich brain regions. In brain regions expressing both the DAT and the norepinephrine transporter (NET), the relative contributions of dopamine and norepinephrine to ADHD pathophysiology and therapeutic response are obfuscated by the capacity of the NET to clear dopamine as well as norepinephrine. Thus, ADHD medications targeting DAT or NET might disperse dopamine widely and consign dopamine storage and release to regulation by noradrenergic, as well as dopaminergic neurons.

Attention-deficit/hyperactivity disorder: a selective overview

Attention-deficit/hyperactivity disorder (ADHD) is a multifactorial and clinically heterogeneous disorder that is associated with tremendous financial burden, stress to families, and adverse academic and vocational outcomes. Attention-deficit/hyperactivity disorder is highly prevalent in children worldwide, and the prevalence of this disorder in adults is increasingly recognized. Studies of adults with a diagnosis of childhood-onset ADHD indicate that clinical correlates--demographic, psychosocial, psychiatric, and cognitive features--mirror findings among children with ADHD. Predictors of persistence of ADHD include family history of the disorder, psychiatric comorbidity, and psychosocial adversity. Family studies of ADHD have consistently supported its strong familial nature. Psychiatric disorders comorbid with childhood ADHD include oppositional defiant and conduct disorders, whereas mood and anxiety disorders are comorbid with ADHD in both children and adults. Pregnancy and delivery complications, maternal smoking during pregnancy, and adverse family environment variables are considered important risk factors for ADHD. The etiology of ADHD has not been clearly identified, although evidence supports neurobiologic and genetic origins. Structural and functional imaging studies suggest that dysfunction in the fronto-subcortical pathways, as well as imbalances in the dopaminergic and noradrenergic systems, contribute to the pathophysiology of ADHD. Medication with dopaminergic and noradrenergic activity seems to reduce ADHD symptoms by blocking dopamine and norepinephrine reuptake. Such alterations in dopaminergic and noradrenergic function are apparently necessary for the clinical efficacy of pharmacologic treatments of ADHD.

Behavioural problems and psychiatric symptoms in 5-13 year-old Swedish children-a comparison of parent ratings on the FTF (Five to Fifteen) with the ratings on CBCL (Child Behavior Checklist)

As part of the validation procedure of a new parent questionnaire ("Five to Fifteen" or the FTF) a random sample of 1500 children aged 5-13 years from the Swedish Population Register (SPAR) was approached. The FTF and the Child Behavior Checklist (CBCL) were sent to the parents of the children together with questions about background conditions. After two reminders the response rate was 55.6%. The final sample had a mean age of 9.12 years (SD=1.89) and a sex distribution with 55% boys and 45% girls. Analysis of attrition did not support overrepresentation of foreigners/immigrants in the attrition population. FTF like CBCL showed sensitivity to sociodemographic variables. On the FTF fewer problems were indicated for girls in all domain scales, whereas this was true for the summary scale Externalizing and Mixed problems of the CBCL. The effects of age and area of residence were slight, but parental education was negatively related to all domain scales of the FTF and to all the CBCL scales. The intercorrelations of the FTF and CBCL scales with common content showed substantial overlap supporting the validity of the FTF scales. The correlation between scales within the FTF however also indicates a substantial comorbidity. This is also supported by the substantial correlation between problem score of the FTF domains perception, language, motor skills and the CBCL scale scores Attention, Social problems as well as the summary scale Mixed problems. These findings indicate that problems with inattention and social relations are shared across the various problem domains. Factor analysis of the FTF subdomain scores resulted in two factors, one representing learning problems and the other behavioural/emotional problems. Despite the low response rate the representativity of the sample was supported by the fact that the total problem score of CBCL was very similar to that of another Swedish sample with a relatively high response rate. The finding of a frequency of AD/HD symptoms in the FTF rating corresponding to the figures of prevalence of AD/HD in several international epidemiological studies could also be seen as support for the relevance of the findings. Thus, the results give support to the usefulness of the FTF questionnaire as an instrument that can help in delineating specific problem areas within the field of child neuropsychiatry. Through the comparison with the CBCL the validity of the FTF for the parts that the two instruments share could be ascertained and the value of tapping a broader problem area could be elucidated.

The occurrence of inattention, hyperactivity, impulsivity and coexisting symptoms in a population study of 471 6-8-year old children based on the FTF (Five to Fifteen) questionnaire

OBJECTIVE

To study the usefulness of a new parent questionnaire and to evaluate the prevalence of inattention, hyperactivity, impulsivity and co-existing problems in a group of 6-8-year-old children.

METHOD

A questionnaire comprising 179 three-score-items including the DSM-IV diagnostic symptom criteria on AD/HD and questions on motor function, executive functions, perception, memory, language and speech, learning, social skills and psychiatric problems was used (5-15 questionnaire, FTF). The answers given by parents of 6-8-year-old children in a community in Finland are presented.

RESULTS

The answers for 471 children, 230 boys and 241 girls, revealed a significantly higher rate of problems for boys than for girls in all developmental domains. The number of children with scores exceeding the mean +2 SD for inattention and/or hyperactivity-impulsivity subdomains were 42. About an half of these children had many coexisting problems, when the 90(th) percentile score for each domain was used as a measurement. Of the 42 children 11 fulfilled the DSM-IV symptom list criteria (6/9 for inattention and/or hyperactivity-impulsivity) for AD/HD and 9 children for subthreshold (5/9) AD/HD.

CONCLUSION

A community-based study revealed that 2.3% of 6-8-year-old children had the full symptom list criteria (6/9) of AD/HD according to DSM-IV, and another 1.9 % fulfilled the symptom criteria (5/9) for subthreshold AD/HD. Coexisting problems were common. The severity of symptoms of inattentiveness and hyperactivity-impulsivity correlated significantly with the severity of coexisting problems.

The FTF (Five to Fifteen): the development of a parent questionnaire for the assessment of ADHD and comorbid conditions

This paper describes the development of a new parent questionnaire ("Five to Fifteen", or the FTF) for elicitation of symptoms and problems typical of ADHD and its comorbidities. The FTF comprises 181 statements related to behavioural or developmental problems that can be endorsed as either "does not apply" (0), applies sometimes or to some extent" (1), "definitely applies" (2), plus a number of open-ended questions including some about the child's strengths. The items are arranged into eight different domains (memory, learning, language, executive functions, motor skills, perception, social skills, and emotional/behavioural problems), most of which can be subdivided into subdomains. For each domain, a mean score ranging from 0-2 can be calculated. A representative sample (n=1350) of the total population of 6-15-year-old children was targeted. Parents of 63% of these completed a questionnaire and returned it to the researchers. Boys showed significantly more problems than did girls across domains and age. Younger children had more problems than pre-adolescents and adolescents (except in the domains of social skills and emotional/behavioural problems). Executive dysfunction was common, and 5.3% of all children in the population had clear problems suggesting a diagnosis of ADHD according to parent report. The paper provides means, medians, and 90(th) and 95(th) centiles for individual items as well as for the eight domains. The Discussion centres on whether or not the FTF can (or should) be used in school-aged children for the identification of children at risk for ADHD or other early childhood onset neuropsychiatric disorder.

The association between hyperkinesis and breakdown of parenting in clinic populations

BACKGROUND

There is increasing recognition that child based, as well as parent based factors may be associated with children being excluded from their families. Despite the distress routinely observed among the parents of hyperactive children, there is little research on this in clinic populations.

AIMS

To examine removals from home in a typical secondary care population, where hyperkinesis was accurately diagnosed.

METHODS

A total of 201 cases were coded using mulitaxial ICD-10 criteria and Jarman indices derived from census data.

RESULTS

Hyperkinetic children were more than three times more likely to have suffered removal from home than children with other psychiatric diagnoses, independent of any psychosocial measure.

CONCLUSION

Hyperkinesis is a specific risk factor for removal from home, which can operate in the absence of other psychosocial stressors. Screening children for hyperactivity is now simple, and the routine paediatric examination for children accommodated by the local authority gives an opportunity for early detection and treatment of hyperactivity in children at risk of family breakdown.

Healthcare use by children with attention deficit/hyperactivity disorder with and without psychiatric comorbidities

This study examined healthcare services used by children with attention-deficit/hyperactivity disorder (ADHD), with and without psychiatric comorbidities. The study was conducted in a large health maintenance organization in the Pacific Northwest on all continuously enrolled children aged 5 to 12 from January 1997 through July 1998. The study measured all outpatient medical care, specialty mental health care services, and prescription drug dispensings from computer records. Children with ADHD, with and without other psychiatric comorbidities, use more general medical services than do other groups of children, including outpatient visits, acute care (emergency room [ER] urgent care) visits. ADHD and other psychiatric comorbidities lead to higher use of specialty mental health services and greater use of psychotropic medications.

Transmission disequilibrium testing of dopamine-related candidate gene polymorphisms in ADHD: confirmation of association of ADHD with DRD4 and DRD5

Attention-deficit hyperactivity disorder (ADHD) is one of the most common childhood behavioral disorders. Genetic factors contribute to the underlying liability to develop ADHD. Reports implicate variants of genes important for the synthesis, uptake, transport and receptor binding of dopamine in the etiology of ADHD, including DRD4, DAT1, DRD2, and DRD5. In the present study, we genotyped a large multiplex sample of ADHD affected children and their parents for polymorphisms in genes previously reported to be associated with ADHD. Associations were tested by the transmission disequilibrium test (TDT). The sample is sufficient to detect genotype relative risks (GRRs) for putative risk alleles. The DRD4 gene 120-bp insertion/deletion promoter polymorphism displayed a significant bias in transmission of the insertion (chi(2)=7.58, P=0.006) as suggested by an analysis of a subset of these families. The seven repeat allele of the DRD4 48-bp repeat polymorphism (DRD4.7) was not significantly associated with ADHD in the large sample in contrast to our earlier findings in a smaller subset. We replicate an association of a dinucleotide repeat polymorphism near the DRD5 gene with ADHD by showing biased nontransmission of the 146-bp allele (P=0.02) and a trend toward excess transmission of the 148-bp allele (P=0.053). No evidence for an association was found for polymorphisms in DRD2 or DAT1 in this sample. The DRD5 146-bp (DRD5.146) allele and the DRD4 240-bp (DRD4.240) allele of the promoter polymorphism emerge as the two DNA variants showing a significant association in this large sample of predominantly multiplex families with ADHD, with estimated GRRs of 1.7 and 1.37, respectively.

Attention-deficit/hyperactivity disorder: increased costs for patients and their families

OBJECTIVE

To estimate the direct (medical and prescription drug) and indirect (work loss) costs of children treated for attention-deficit/hyperactivity disorder (ADHD) and their family members.

METHOD

The data source was an administrative database from a national, Fortune 100 manufacturer that included all medical, pharmaceutical, and disability claims for beneficiaries (n > 100,000). The analysis involved four samples. The ADHD patient sample included individuals age 18 or younger with at least one ADHD claim during the study period (1996-1998). Resource utilization of ADHD patients was contrasted with a matched control sample of patients who did not have claims for ADHD. The ADHD and non-ADHD family samples included non-ADHD family members of ADHD patients and their matched controls.

RESULTS

The annual average expenditure (direct cost) per ADHD patient was $1,574, compared to $541 among matched controls. The annual average payment (direct plus indirect cost) per family member was $2,728 for non-ADHD family members of ADHD patients versus $1,440 for family members of matched controls. Both patient and family cost differences were significant at the 95% confidence level.

CONCLUSIONS

ADHD imposes a significant financial burden regarding the cost of medical care and work loss for patients and family members.

Advances in the Pharmacotherapy of Attention-Deficit–Hyperactivity Disorder: Focus on Methylphenidate Formulations

The psychostimulant dl-methylphenidate (MPH) remains the most common drug therapy in child and adolescent psychiatry for the treatment of attention-deficit-hyperactivity disorder (ADHD). Evidence of a dopaminergic basis both for the actions of MPH and for the underlying neuropathology in ADHD continues to mount. Advances in the biopharmaceutics of MPH have been conspicuous. Novel approaches to formulation design have resulted in new MPH delivery options to overcome the short-term actions of both immediate-and sustained-release MPH. New modified-release MPH products offer the convenience of once-daily administration while providing extended absorption profiles that better mimic those of standard schedules of immediate-release MPH (i.e., the absorption phase of MPH better correlates with improved behavioral response than does the elimination phase). The oral bioavailability of MPH in females may be lower than in males. The l-MPH isomer exhibits only negligible oral bioavailability and, further, possesses little intrinsic activity at the dopamine transporter. This notwithstanding, a single-isomer d-MPH immediate-release product is now available for dosing recommended at one-half that of dl-MPH.

Attention-deficit/hyperactivity disorder in children and adolescents: interventions for a complex costly clinical conundrum

Management of a child or adolescent with attention-deficit/hyperactivity disorder (ADHD) is reviewed, including psychological and pharmacologic approaches. Psychological treatment includes psychotherapy, cognitive-behavior therapy, support groups, parent training, educator/teacher training, biofeedback, meditation, and social skills training. Medications are reviewed that research has revealed can improve the core symptomatology of a child or adolescent with ADHD. These medications include stimulants, antidepressants, alpha-2 agonists, and a norepinephrine reuptake inhibitor. Management of ADHD should include a multi-modal approach, involving appropriate educational interventions, appropriate psychological management of the patient (child or adolescent), and judicious use of medications. Parents, school officials, and clinicians must work together to help all children and adolescents with ADHD achieve their maximum potential.

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 open trial of bupropion for the treatment of adults with attention-deficit/hyperactivity disorder and bipolar disorder

BACKGROUND

Despite the increasing recognition of comorbid attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BPD) in adults, there are no prospective trials of pharmacological agents to treat ADHD in these patients. Given the efficacy of bupropion for ADHD in adults, as well as its use in the management of bipolar depression, we studied the tolerability and efficacy of sustained-release (SR) bupropion in adults with ADHD plus BPD.

METHODS

This was an open, prospective, 6-week trial of bupropion SR (up to 200 mg b.i.d.) in adults with DSM-IV ADHD plus historical bipolar I disorder (BPD I) (10%) or bipolar II disorder (BPD II) (90%). Adults receiving adjunct antimanic agents (mood stabilizers and antipsychotics) at baseline were included in the study. We used standardized psychiatric instruments for diagnosis and outcome. Efficacy was based primarily on the Clinical Global Impression Scale (CGI) for ADHD and the ADHD symptom checklist.

RESULTS

Of 36 patients entered (75% male, mean age 34 years), 30 patients (83%) completed the protocol. At end point (last observation carried forward [LOCF]) compared to baseline, treatment with bupropion SR resulted in significant reductions in the ADHD symptom checklist (-55%, z = 5.63, p <.001) and CGI severity of ADHD (-40%, z = 6.285, p <.001). Bupropion was associated with reductions in ratings of mania and depression.

CONCLUSIONS

The results from this open study of adults with ADHD plus BPD suggest that sustained-release bupropion may be effective in treating ADHD in the context of a lifetime diagnosis of BPD, without significant activation of mania. Further controlled trials are warranted.

Pharmacokinetics of methylphenidate after oral administration of two modified-release formulations in healthy adults

OBJECTIVE

To compare the rate and extent of absorption of DL-threo-methylphenidate (MPH) from two modified-release MPH formulations at their respective recommended starting doses in healthy adult volunteers.

DESIGN

Open-label, randomised, crossover, bioavailability study.

PARTICIPANTS

Twenty healthy adult male and female volunteers.

METHODS

Subjects received single doses of two modified-release formulations of MPH, a 20mg capsule (Ritalin) LA) and an 18 mg tablet (Concerta). A total of 19 plasma samples was collected over 24 hours, and MPH plasma concentrations were determined by liquid chromatography-mass spectrometry (LC-MS/MS). These values were used to calculate standard noncompartmental pharmacokinetic parameters describing the rate (peak concentration and time to peak concentration) and extent (area under the concentration-time curve, AUC) of absorption of the two formulations. The relative bioavailability of the two drugs was assessed using a 90% confidence interval, based on the lower and upper endpoints of the confidence interval for the ratios of the geometric means (log transformed) being within the 0.80-1.25 equivalence criterion.

RESULTS

Nineteen subjects, ten male and nine female, aged 21-34 years completed both treatment phases of the study. The Ritalin LA formulation displayed a distinctly biphasic pharmacokinetic profile, with mean initial peak plasma concentration of 7 microg/L at an average of 2.1 hours after administration and a second peak of 9.3 microg/L occurring at 5.6 hours. In contrast, the profile of the Concerta formulation rapidly reached an initial plateau concentration of 3.4 microg/L at 3.3 hours after administration and a second mean plateau concentration of 5.9 microg/L approximately 6 hours after administration. Substantially more MPH was absorbed from Ritalin LA than from Concert over the first 4 hours; the respective AUC(4) values were 18.5 and 9.3 microg x h/L (p < 0.001). The overall extent of absorption of MPH was similar between the two formulations. Oral clearance was identical between the two dosage forms.

CONCLUSIONS

The Ritalin LA formulation exhibited more rapid initial absorption and reached significantly higher peak plasma concentrations compared with the Concerta formulation, although the oral bioavailability of MPH was similar between the two formulations. The Ritalin LA capsule demonstrated a distinctly bimodal plasma concentration-time profile. MPH plasma concentrations resulting from Concerta reached a peak at 6 hours. These results indicate that the recommended starting dose of the Ritalin LA 20 mg capsule formulation provides more rapid absorption and higher peak plasma concentrations than the recommended 18 mg starting dose of the Concerta formulation.

Association analysis of monoamine oxidase A and attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is a highly heritable disorder. Although the causes of ADHD are unknown, dopaminergic, serotonergic and nor-adrenergic pathways have been strongly implicated. Monoamine Oxidase A (MAOA) is involved in the degradation of all three of these neurotransmitters and therefore has been suggested as a strong candidate gene for ADHD. Animal and human studies have implicated MAOA and 5-HT in impulsive and aggressive behavior. We therefore additionally postulated that MAOA might be associated with a subtype of ADHD where aggressive and impulsive features are especially prominent. We have tested this hypothesis by genotyping two polymorphisms (the 30-bp VNTR in the promoter and the Fnu4HI 941T-->G) in MAOA that are associated with altered MAOA function. Our sample consisted of 171 British Caucasian children 6-16 years of age fulfilling DSM-III R, DSM-IV or ICD-10 criteria for ADHD/Hyperkinetic Disorder. Using case control analysis and then the TDT, no association was found between these two MAOA polymorphisms and ADHD. Case control analysis of the VNTR showed an association with a subgroup of children with comorbid conduct problems (OR = 2.0, 95% CI = 1.09, 3.5), and TDT analysis indicated a statistical trend toward association. Our findings highlight the importance of phenotype definition and the need for the MAOA VNTR to be further examined.

Efficacy of methylphenidate in patients with cerebral palsy and attention-deficit hyperactivity disorder (ADHD)

Our objective was to study the short-term efficacy and safety of methylphenidate in patients with the dual diagnosis of cerebral palsy and attention-deficit hyperactivity disorder (ADHD). Twenty-nine patients (8.0 +/- 4.0 years old) with cerebral palsy and ADHD completed the study. In a prospective, crossover, double-blind paradigm, patients were treated with methylphenidate or placebo, each for 4 weeks. Parents and teachers completed a modified Abbreviated Conners' Rating Scale at the beginning of the study and the end of the first and second months of treatment with methylphenidate or placebo. Parents were contacted weekly to report side effects. Methylphenidate treatment, as assessed by teachers' ratings, resulted in a significant improvement in ADHD symptomatology (t = 2.29, df = 27, P < .05); however, a trend for improvement was noted only on the parents' ratings. After the conclusion of the study, 12 patients continued methylphenidate for 20 +/- 10 months. Side effects were minimal, with the exception of transient hallucinations in one patient. In children with cerebral palsy and ADHD, methylphenidate is effective, rendering it a valuable adjunct to their overall medical therapy.

Conduct problems, gender and adult psychiatric outcome of children with attention-deficit hyperactivity disorder

BACKGROUND

Attention-deficit hyperactivity disorder (ADHD) is a common childhood condition, and is more prevalent in boys. The adult outcome of girls with ADHD has never been studied.

AIMS

To identify predictors for adult psychiatric outcome of children with ADHD, including gender and comorbidity.

METHOD

Children aged 4-15 years, referred for hyperactivity/inattention and treated with stimulants were included (n=208). The Psychiatric Case Register provided follow-up data on psychiatric admissions in adulthood until a mean age of 31 years.

RESULTS

A total of 47 cases (22.6%) had a psychiatric admission in adulthood. Conduct problems in childhood were predictive (hazard ratio HR=2.3; 95% CI 1.22-4.33). Girls had a higher risk compared with boys (HR=2.4; 95% CI 1.1-5.6).

CONCLUSIONS

Girls with ADHD had a higher risk of adult psychiatric admission than boys. Conduct problems were also associated with a higher risk. Girls with ADHD with conduct problems had a very high risk of a psychiatric admission in adulthood.

Attention dysfunction predicts substance involvement in community youths

OBJECTIVE

Cognitive impairments influence alcohol and drug treatment outcomes, though little is known about how neurocognition affects the development of harmful substance use patterns. This study examined the influence of adolescent attention functioning on the development of substance use problems in 66 high-risk youths over an 8-year period.

METHOD

Participants were community youths who were free from any history of substance use disorders, neurological illness, and mood, anxiety, or psychotic disorders at project intake and were administered neuropsychological tests and substance involvement interviews from ages 15 through 23 on average. Substance involvement was assessed by self-report, resource person reports, and randomly sampled toxicology screens.

RESULTS

Attention/executive functioning scores obtained at the intake neuropsychological assessment significantly predicted substance use and dependence symptoms 8 years later, even after controlling for intake substance involvement, gender, education, conduct disorder, family history of substance use disorders, and learning disabilities.

CONCLUSIONS

These results suggest that adolescents with limited attentional abilities, but not necessarily attention-deficit/hyperactivity disorder diagnoses, may be at risk for developing more problematic alcohol and drug involvement. Thus prevention and treatment efforts should target youths with attentional difficulties by using programs that are effective for those with compromised concentration and processing abilities.

Temperamental correlates of disruptive behavior disorders in young children: preliminary findings

BACKGROUND

Our objective was to test the hypothesis that temperamental behavioral disinhibition measured in early childhood would be associated with disruptive behavior disorders.

METHODS

We used variables from laboratory-based behavioral observations originally devised to assess behavioral inhibition to construct a theory-based a priori definition of "behavioral disinhibition" in 200 young children at-risk for panic disorder, depression, or both and 84 children of parents without anxiety or major depressive disorder. We then compared behaviorally disinhibited and nonbehaviorally disinhibited children on rates of DSM-III-R disorders and measures of academic and social dysfunction.

RESULTS

Behavioral disinhibition was significantly associated with higher rates of disruptive behavior disorders and mood disorders. Children with behavioral disinhibition were significantly more likely than nondisinhibited, noninhibited children to have attention-deficit/hyperactivity disorder (ADHD) and to have comorbid mood and disruptive behavior disorders. Moreover, disinhibited children had lower Global Assessment of Functioning Scale scores and were more likely to have been in special classes and to have problems with school behavior and leisure activities.

CONCLUSIONS

These results suggest that behavioral disinhibition may represent a temperamental precursor to disruptive behavior problems, particularly ADHD. Longitudinal studies using behavioral assessments of behavioral disinhibition are needed to confirm these findings.

Pharmacokinetic and pharmacodynamic drug interactions in the treatment of attention-deficit hyperactivity disorder

The psychostimulants methylphenidate, amphetamine and pemoline are among the most common medications used today in child and adolescent psychiatry for the treatment of patients with attention-deficit hyperactivity disorder. Frequently, these medications are used in combination with other medications on a short or long term basis. The present review examines psychostimulant pharmacology, summarises reported drug-drug interactions and explores underlying pharmacokinetic and pharmacodynamic considerations for interactions. A computerised search was undertaken using Medline (1966 to 2000) and Current Contents to provide the literature base for reports of drug-drug interactions involving psychostimulants. These leads were further cross-referenced for completeness of the survey. Methylphenidate appears to be more often implicated in pharmacokinetic interactions suggestive of possible metabolic inhibition, although the mechanisms still remain unclear. Amphetamine was more often involved in apparent pharmacodynamic interactions and could potentially be influenced by medications affecting cytochrome P450 (CYP) 2D6. No published reports of drug interactions involving pemoline were found. The alpha2-adrenergic agonists clonidine and guanfacine have been implicated in several interactions. Perhaps best documented is their antagonism by tricyclic antidepressants and phenothiazines. In additional, concurrent beta-blocker use, or abrupt discontinuation, can lead to hypertensive response. Although there are few published well-controlled interaction studies with psychostimulants and alpha2-adrenergic agonists, it appears that these agents may be safely coadministered. The interactions of monoamine oxidase inhibitors with psychostimulants represent one of the few strict contraindications.

The dopamine transporter: relevance to attention deficit hyperactivity disorder (ADHD)

The dopamine transporter is elevated in adults with attention deficit hyperactivity disorder (ADHD) compared with healthy controls [Lancet 354 (1999) 2132]. The findings have been confirmed by others in a different population using a different probe for the dopamine transporter. Notwithstanding the need to confirm these findings in a multi-center trial, several hypotheses are presented to account for these observations. A premise that elevated transporter levels result from medication is not supported by current data. Other possibilities, including hypertrophy of dopamine neuronal terminals in the striatum, dysfunctional regulation of dopamine or dopamine receptors, or anomalies in the dopamine transporter gene are presented as hypotheses. The feasibility of exploring these mechanisms in animal models or in human subjects is explored.

Psychological heterogeneity in AD/HD--a dual pathway model of behaviour and cognition

Psychological accounts have characterised attention-deficit/hyperactivity disorder (AD/HD) as either a neuro-cognitive disorder of regulation or a motivational style. Poor inhibitory control is thought to underpin AD/HD children's dysregulation while delay aversion is a dominant characteristic of their motivational style. A recent 'head to head' study of these two accounts suggest that delay aversion and poor inhibitory control are independent co-existing characteristics of AD/HD (combined type). In the present paper we build on these findings to propose a dual pathway model of AD/HD that recognises two quite distinct sub-types of the disorder. In one AD/HD is the result of the dysregulation of action and thought resulting from poor inhibitory control associated with the meso-cortical branch of the dopamine system projecting in the cortical control centres (e.g. pre-frontal cortex). In the other AD/HD is a motivational style characterised by an altered delay of reward gradient linked to the meso-limbic dopamine branch associated with the reward circuits (e.g. nucleus accumbens). The two pathways are further distinguished at the levels of symptoms, cognitive and motivation profiles and genetic and non-genetic origins.

The contribution of comparative studies in inbred strains of mice to the understanding of the hyperactive phenotype

Attention-deficit hyperactivity disorder (ADHD) is a highly prevalent childhood psychiatric disorder characterized by impaired attention, excessive motor activity and impulsivity. Converging evidence, suggests a primary role of disturbances in brain dopamine (DA) transmission and a role of genetic factors in its pathology. Inbred provide a well-defined and stable genotype for analysis. C57BL/6 (C57) and DBA/2 (DBA) mice are amongst the most studied inbred strains in the behavioral pharmacology of DA, and they differ in several parameters of the DA system that relate directly to behavioral differences. These strains also exhibit several qualitatively different behavior patterns that rely on separate DA networks (e.g. mesoaccumbens vs. nigrostriatal) and on different modes of inheritance. C57 mice are good learners in most tasks also involving associative learning but are totally unable to learn active avoidance although being very active. Moreover, C57 mice show greater novelty-induced locomotor activity than DBA, which is modulated strongly by DA neurons in the ventral tegmental area (VTA) region. Pharmacological studies also indicate a facilitated mesoaccumbens DA transmission in C57 mice when compared to DBAs. Increased density of D2 autoreceptors located on VTA neurons, and lower D2 postsynaptic receptors in the NAS were observed in DBA relative to C57. Activation of D2 autoreceptors inhibits impluse flow, synthesis, and release rates of DA neurons. As would be predicted from their higher D2 autoreceptor: DBA compared to C57 mice show reduced DA synthesis and release within the mesoaccumbens DA system when challenged with DA direct agonists. However, DBA mice are by fare more susceptible than C57s to stress-induced enhanced mesoaccumbens DA release and in stressful situation, they show sustained active behavioral responses whilst C57 adopt extremely passive responses (behavioral despair). Finally, chronic or repeated stress promote opposite adaptation of VTA DA autoreceptors in the two strains and render the hypoactive DBAs as active as the C57 mice. These results indicate that a complex interaction between genetic and environmental factors controls, mesoaccumbens DA functioning and hyperactive phenotype.

The effects of exercise on children with attention-deficit hyperactivity disorder

PURPOSE

The effects of exercise on children with attention-deficit hyperactivity disorder (ADHD) were evaluated by studying the rate of spontaneous eye blinks, the acoustic startle eye blink response (ASER), and motor impersistence among 8- to 12-yr-old children (10 boys and 8 girls) meeting DSM-III-R criteria for ADHD.

METHODS

Children ceased methylphenidate medication 24 h before and during each of three daily conditions separated by 24-48 h. After a maximal treadmill walking test to determine cardiorespiratory fitness (VO(2peak)), each child was randomly assigned to counterbalanced conditions of treadmill walking at an intensity of 65-75% VO(2peak) or quiet rest. Responses were compared with a group of control participants (11 boys and 14 girls) equated with the ADHD group on several key variables.

RESULTS

Boys with ADHD had increased spontaneous blink rate, decreased ASER latency, and decreased motor impersistence after maximal exercise. Girls with ADHD had increased ASER amplitude and decreased ASER latency after submaximal exercise.

CONCLUSIONS

The findings suggest an interaction between sex and exercise intensity that is not explained by physical fitness, activity history, or selected personality attributes. The clinical meaning of the eye blink results is not clear, as improvements in motor impersistence occurred only for boys after maximal exercise. Nonetheless, these preliminary findings are sufficiently positive to encourage additional study to determine whether a session of vigorous exercise has efficacy as a dopaminergic adjuvant in the management of behavioral features of ADHD.

Unsuspected depressive mania in pre-pubertal Hispanic children referred for the treatment of 'depression' with history of social 'deviance'

BACKGROUND

Despite an emerging Literature on the mixed nature of pediatric mania, initial presentation with conduct problems continues to mislead mental health clinicians. The present report focuses on Hispanic pre-pubertal children referred for the treatment of depression in the context of conduct problems.

METHODS

Eleven boys and two girls received a structured psychiatric assessment in a practice setting to make sense of the presenting clinical complexity. Diagnoses were assigned using the DSM-IV criteria.

RESULTS

Ten of the boys and both girls met criteria for depressive mania. Their family histories were replete with affective disorder. Five (50%) of the boys and both of the girls (100%) with depressive mania had family histories of bipolar disorder. Six (60%) of the boys and neither of the girls with depressive mania had psychotic features. Those with depressive mania exhibited clear-cut circadian changes in symptomatology. Euphoria, oscillating with affective states indicative of psychic pain, was characteristically restricted to the evenings or nighttime. However, the drive to seek treatment had stemmed from social 'deviance'.

CONCLUSION

Children with depressive mania are often unrecognized in clinical settings. Boys with conduct problems may be disproportionately represented among such children. These data support Akiskal's hypothesis that externalizing (conduct) problems in clinically referred children with depression are indicative of bipolar disorder.

Transkranielle Magnetstimulation in der Kinder- und Jugendpsychiatrie: Exzitabilität des motorischen Systems bei Tic-Störungen und/oder Aufmerksamkeitsdefizit-/ Hyperaktivitätsstörungen

Zusammenfassung: Mit der transkraniellen Magnetstimulation (TMS) kann die Exzitabilität des motorischen Systems direkt in vivo untersucht werden. Diese Methode wurde deshalb bei Kindern mit solchen Störungsbildern angewandt, bei denen sich eine unzureichende Steuerung, Kontrolle und/oder Regulation motorischer Abläufe feststellen lässt: Eine “musterbezogene” Überaktivität bei Tic-Störungen, eine “allgemeine” motorische Überaktivität bei Aufmerksamkeitsdefizit-/Hyperaktivitätsstörungen (ADHS). Im Vergleich zu gesunden Kindern waren bei Kindern mit diesen hypermotorischen Störungsbildern unterschiedliche Auffälligkeiten festzustellen: (1) Eine verkürzte Kortikale Silent Period und damit ein Hinweis auf defizitäre inhibitorische Prozesse wahrscheinlich auf Ebene der Basalganglien bei Kindern mit Tic-Störungen (offenbar kein Einfluss klinisch wirksamer Medikamente), (2) eine verminderte intrakortikale Inhibition und damit ein Hinweis auf defizitäre inhibitorische Prozesse eher im Bereich des Motorkortex bei Kindern mit ADHS (Zunahme der intrakortikalen Inhibition unter Methylphenidatgabe). (3) Bei Kindern mit komorbider ADHS und Tic-Störung waren beide neurophysiologischen Veränderungen i.S. eines “additiven” Inhibitionsdefizites im motorischen System aufzeigbar. Mit diesen TMS-Untersuchungen konnten bei Kindern mit den hypermotorischen Störungsbildern Tic-Störungen und ADHS neue Befunde zur Darstellung neurobiologischer Grundlagen (“Inhibitionsdefizite im motorischen System”), zur Frage der Komorbidität (“additiver Effekt im motorischen System”) sowie zum Wirkmechanismus entsprechender Psychopharmaka (“Verbesserung des Inhibitionsvermögens im motorischen System bei ADHS unter Methylphenidat”) erarbeitet werden.

Effects of lithium chloride on induction and expression of methylphenidate sensitization

Repeated administration of psychomotor stimulants produces an enduring and progressively enhanced behavioral response known as behavioral sensitization, which has been implicated as a model for psychiatric disorders such as mania, schizophrenia, and drug addiction. The objective of the study was to determine whether lithium chloride (LiCl), an anti-manic agent, is effective in blocking the development and/or the expression of behavioral sensitization to methylphenidate. Male Sprague-Dawley rats (n=64) weighing 170-190 g were randomly divided into seven treatment groups. A computerized animal activity monitor system continuously recorded locomotor activity for 16 days. Effects of LiCl on induction of methylphenidate sensitization were studied by giving LiCl before or during six daily methylphenidate administrations. Effects of LiCl on the expression of methylphenidate sensitization were studied by injecting LiCl after sensitization to methylphenidate was induced. It was shown that LiCl treatment modulated the acute methylphenidate effects by transiently attenuating the locomotor response to methylphenidate during the six daily methylphenidate administrations but neither single nor multiple treatments with LiCl blocked the development or the expression of behavioral sensitization.