The prevalence of ADHD: its diagnosis and treatment in four school districts across two states.

OBJECTIVE: To describe the epidemiology of ADHD in communities using a DSM-IVTR case definition. METHOD: This community-based study used multiple informants to develop and apply a DSM -IVTR-based case definition of ADHD to screening and diagnostic interview data collected for children 5-13 years of age. Teachers screened 10,427 children (66.4%) in four school districts across two states (SC and OK). ADHD ratings by teachers and parent reports of diagnosis and medication treatment were used to stratify children into high and low risk for ADHD. Parents (n = 855) of high risk and gender frequency-matched low risk children completed structured diagnostic interviews. The case definition was applied to generate community prevalence estimates, weighted to reflect the complex sampling design. RESULTS: ADHD prevalence was 8.7% in SC and 10.6% in OK. The prevalence of ADHD medication use was 10.1% (SC) and 7.4% (OK). Of those medicated, 39.5% (SC) and 28.3% (OK) met the case definition. Comparison children taking medication had higher mean symptom counts than other comparison children. CONCLUSIONS: Our ADHD estimates are at the upper end of those from previous studies. The identification of a large proportion of comparison children taking ADHD medication suggests that our estimates may be conservative; these children were not included as cases in the case definition, although some might be effectively treated.

The psychometric properties of the Vanderbilt attention-deficit hyperactivity disorder diagnostic parent rating scale in a community population.

OBJECTIVE: To examine the psychometric properties of the Vanderbilt ADHD Diagnostic Parent Rating Scale (VADPRS) using a community-based sample of primarily elementary and middle school-aged children. METHOD: Participants were initially recruited from 41 elementary schools in 5 Oklahoma school districts including urban, suburban, and rural students. Vanderbilt rating scales were obtained from all teachers (n = 601) and sampled parents (n = 587) of the participating children. Construct validity was assessed by confirmatory factor analysis of the 45 items that made up the 4 scales of inattention, hyperactivity, conduct/oppositional problems, and anxiety/depression problems. Reliability was evaluated from internal consistency, test-retest, and interrater agreement perspectives. Criterion validity was evaluated via comparisons to a structured psychiatric interview with the parents using the Diagnostic Interview Schedule for Children-IV. RESULTS: A 4-factor model (inattention, hyperactivity, conduct/oppositional problems, and anxiety/depression problems) fit the data well once discarding conduct items that were infrequently endorsed. The estimates of coefficient alpha ranged from .91 to .94 and the analogous KR20 coefficient for a binary item version of the scale ranged from .88 to .91. Test-retest reliability exceeded .80 for all summed scale scores. The VADPRS produced a sensitivity of .80, specificity of .75, positive predictive value of .19, and negative predictive value of .98 when predicting an attention-deficit hyperactivity disorder (ADHD) case definition that combined teacher's Vanderbilt ADHD Diagnostic Teacher Rating Scale and parent diagnostic interview responses. CONCLUSION: The confirmation of the construct and concurrent criterion validities found in this study further support the utility of the VADPRS as a diagnostic rating scale for ADHD.

The psychometric properties of the Vanderbilt attention-deficit hyperactivity disorder diagnostic teacher rating scale in a community population.

OBJECTIVE: This study examined the psychometric properties of the Vanderbilt AD/HD Diagnostic Teacher Rating Scale (VADTRS). METHODS: Information was collected from teachers and parents in 5 school districts (urban, suburban, and rural). All teachers in participating schools were asked to complete the VADTRS on all their students. Construct validity was evaluated through an exploratory factor analysis investigation of the 35 items that made up the 4 scales of inattention, hyperactivity, conduct/oppositional problems, and anxiety/depression problems. Convergent validity was assessed among a subsample of participants whose teachers completed the Strengths and Difficulties Questionnaire (SDQ). Finally, predictive validity was examined for another subsample of high- and low-risk children whose parents completed a structured psychiatric interview, the Diagnostic Interview Schedule for Children-IV. RESULTS: For construct validity, a 4-factor model (inattention, hyperactivity, conduct/oppositional, and anxiety/depression problems) fits the data well. The estimates of the KR20 coefficient for a binary item version of the scale ranged from .85 to .94. Convergent validity with the SDQ was high (Pearson's correlations > .72) for these 4 factors. For predictive validity, the VADTRS produced a sensitivity of .69, specificity of .84, positive predictive value of .32, and negative predictive value of .96 when predicting future case definitions among children whose parents completed a diagnostic interview. CONCLUSION: The confirmation of the construct and convergent validity and acceptable scale reliabilities found in this study further supports the utility of the VADTRS as a diagnostic rating scale for attention-deficit hyperactivity disorder. The low predictive validity further demonstrates the need for multiple observers in establishing the diagnosis.

Treatment of attention deficit hyperactivity disorder in children and adolescents: safety considerations.

Despite a large body of evidence for both the validity of the diagnosis of attention deficit hyperactivity disorder (ADHD) and the efficacy of its treatment with medication, there is an equally long history of controversy. This article focuses on presenting safety information for medications approved by the US FDA for the treatment of individuals with ADHD. Stimulant medications are generally safe and effective. The common adverse effects of stimulant medications, including appetite suppression and insomnia, are usually of mild severity and manageable without stopping the medication. The more severe adverse effects such as tics or bizarre behaviours occur with low frequency and usually resolve when the medication is stopped. The possible impact on growth requires careful monitoring. Several rare but potentially severe adverse effects including sudden cardiac death and cancer following long-term treatment have been reported; however, these effects have not been adequately demonstrated to be of significant concern at this time. Atomoxetine also has a mild adverse effect profile in terms of severity and frequency although the numbers of studies and years of clinical experience is considerably less with this drug than for the stimulant medications. When the risks are juxtaposed to the clear efficacy in significantly reducing dysfunctional symptoms of ADHD, benefit-risk analyses support the continued use of these pharmacological treatments for patients with ADHD.

Intervening to improve communication between parents, teachers, and primary care providers of children with ADHD or at high risk for ADHD.

This study examines interventions designed to improve communication between individuals who take care of children with ADHD. A teacher rating of 6,171 elementary school children identifies 1,573 children with ADHD or with high risk for ADHD. Parent interviews and information from teachers are collected on 243 children who are randomized into treatment and control conditions and followed for 39 months. The interventions consisted of group workshops and single one-on-one tutorials with parents, teachers, and providers about the evaluation and treatment of ADHD that stressed the need for communication between the three parties. There are few significant effects on communication that are short lived. Results suggest that the interventions are insufficient to cause significant increase in communication. Future attempts to improve parent-teacher-provider coordination should be continuing rather than single-session interventions.

Pharmacokinetic considerations in the treatment of attention-deficit hyperactivity disorder with methylphenidate.

Methylphenidate is commonly used for the treatment of attention-deficit hyperactivity disorder (ADHD). Its efficacy in improving the core symptoms of ADHD, as well as some of the aggressive and oppositional behaviours, is well documented, based on a large volume of research. Methylphenidate has a wide margin of safety and relatively mild adverse effects, most commonly appetite suppression and insomnia. Methylphenidate is a rapidly absorbed medication that, in its d-isomer form, readily penetrates the CNS, particularly the striatum. It appears to function by blocking the reuptake of dopamine. Both the plasma concentrations and behavioural effects of methylphenidate demonstrate a time to maximum of between 1 and 3 hours, with the maximum behavioural effects occurring when the plasma concentrations are increasing. Because of the rapid onset of action, the effects of methylphenidate can be dramatic but usually last only about 4 hours with the immediate-release formulation. The behavioural responses of individuals are also highly variable, so that it is necessary to start treatment at a low dosage and increase up to a maximally effective dosage (usually starting at 10-15 mg/day with increases of 10-15mg at weekly intervals to a maximum dosage of 60 mg/day, irrespective of formulation). Because of the variability in behavioural responses, assessment of plasma concentrations is not clinically useful nor does weight help in deciding an appropriate dosage. The difficulties in administering methylphenidate multiple times a day, particularly during the school day, have been alleviated in the past few years by the development of extended-release preparations with varying behavioural effects lasting 8-12 hours. The 8-hour preparations (Metadate) CD and Ritalin) LA) utilise a microbead technology, while the 12-hour preparation (Concerta) utilises an osmotic pump system. All extended-release formulations effectively control the symptoms of ADHD. While pharmacokinetic differences appear to exist between some of these new formulations, there are currently no clinical data available to demonstrate clinical efficacy differences between them.

Assessing the impact of parent and teacher agreement on diagnosing attention-deficit hyperactivity disorder.

This study examines the impact of interrater reliability on the diagnosis of attention-deficit hyperactivity disorder (ADHD). A screening of 6171 elementary school children identified 1573 children with a high risk for ADHD according to teacher rating. Follow-up parent interviews and information from teachers were collected on 243 children. Before screening, health care professionals had diagnosed ADHD in 40% of the identified children. There was low agreement between the parent and teacher reports of ADHD symptoms according to DSM-IV-based questionnaires: Inattentive (r =.34, kappa = 0.27), Hyperactive/Impulsive (r =.27, kappa = 0.22), and Performance Impairment (r =.31, kappa = 0.07). When the two-setting requirement was strictly enforced, poor interrater agreement decreased diagnostic rates for all three types of ADHD in this clinical sample: Inattentive (15%-5%), Hyperactive/Impulsive (11%-3%), and Combined (23%-7%). Parent and teacher agreement was low concerning ADHD symptoms and performance. The recommendation of multiple informants significantly decreased the prevalence. Allowing for observer disagreement by using more lenient core symptom scores could reduce the effect.

Psychometric properties of the Vanderbilt ADHD diagnostic parent rating scale in a referred population.

OBJECTIVE: s To determine the psychometric properties of the Vanderbilt Attention Deficit/Hyperactivity Disorder Parent Rating Scale (VADPRS), which utilizes information based on the Diagnostic and Statistical Manual of Mental Disorders, 4th Ed. (DSM-IV). The VADPRS was created to collect uniform patient data and minimize the time burden of lengthy interviews. METHODS: Participant data (N = 243) was used from the first 2 years of a longitudinal study on communication among physicians, teachers, and parents in diagnosing, treating, and managing children with attention deficit/hyperactivity disorder (ADHD). The reliability, factor structure, and concurrent validity of the VADPRS were evaluated and compared with ratings of children in clinical and nonclinical samples on the Vanderbilt ADHD Teacher Rating Scale and the Computerized Diagnostic Interview Schedule for Children-IV, Parent version. RESULTS: The internal consistency and factor structure of the VADPRS are acceptable and consistent with DSM-IV and other accepted measures of ADHD. CONCLUSION: The VADPRS is a reliable, cost-effective assessment for ADHD in clinical and research settings.

Teachers' screening for attention deficit/hyperactivity disorder: comparing multinational samples on teacher ratings of ADHD.

This study evaluates a measurement model for Attention Deficit/Hyperactivity Disorder (ADHD). The DSM-IV divides 18 symptoms into two groups, inattentive and hyperactive/impulsive. Elementary school teachers rated 21,161 children in 4 locations: Spain, Germany, urban US, and suburban US. Confirmatory factor analysis suggested that the 2-factor model (inattention, hyperactivity/impulsivity) shows the best fit. A third factor, impulsivity, was too slight to stand-alone. Children with academic performance problems were distinguished by inattention, but children with behavior problems typically had elevations in inattention, hyperactivity, and impulsivity. Between-site differences were statistically significant, but so small that we conclude that same measurement model fits all 4 samples in 2 continents.