Methylphenidate-elicited dopamine increases in ventral striatum are associated with long-term symptom improvement in adults with attention deficit hyperactivity disorder.

Stimulant medications, such as methylphenidate, which are effective treatments for attention deficit hyperactivity disorder (ADHD), enhance brain dopamine signaling. However, the relationship between regional brain dopamine enhancement and treatment response has not been evaluated. Here, we assessed whether the dopamine increases elicited by methylphenidate are associated with long-term clinical response. We used a prospective design to study 20 treatment-naive adults with ADHD who were evaluated before treatment initiation and after 12 months of clinical treatment with a titrated regimen of oral methylphenidate. Methylphenidate-induced dopamine changes were evaluated with positron emission tomography and [(11)C]raclopride (D(2)/D(3) receptor radioligand sensitive to competition with endogenous dopamine). Clinical responses were assessed using the Conners' Adult ADHD Rating Scale and revealed a significant reduction in symptoms of inattention and hyperactivity with long-term methylphenidate treatment. A challenge dose of 0.5 mg/kg intravenous methylphenidate significantly increased dopamine in striatum (assessed as decreases in D(2)/D(3) receptor availability). In the ventral striatum, these dopamine increases were associated with the reductions in ratings of symptoms of inattention with clinical treatment. Statistical parametric mapping additionally showed dopamine increases in prefrontal and temporal cortices with intravenous methylphenidate that were also associated with decreases in symptoms of inattention. Our findings indicate that dopamine enhancement in ventral striatum (the brain region involved with reward and motivation) was associated with therapeutic response to methylphenidate, further corroborating the relevance of the dopamine reward/motivation circuitry in ADHD. It also provides preliminary evidence that methylphenidate-elicited dopamine increases in prefrontal and temporal cortices may also contribute to the clinical response.

Prevalence of ADHD symptoms in patients with congenital heart disease.

OBJECTIVE: The presence of attention-deficit-hyperactivity disorder (ADHD) symptoms in children with congenital heart disease (CHD) was investigated. METHODS: Swanson, Nolan and Pelham teacher and parent rating scales, version 4 (SNAP-IV), commonly used for assessing symptoms of ADHD, were completed by parents and counselors of children who attended a CHD summer camp. Mean scores (n = 51) were compared with two comparison groups without CHD: patients with ADHD (n = 75) and patients without ADHD (n = 41). Parent scores were also compared to previously published parent normative data. RESULTS: Patients with CHD were reported to have elevated SNAP-IV scores by parents and counselors (11.8%). Parent ratings of inattention were significantly greater in CHD subjects when compared to the comparison group without ADHD (P < 0.001), and similar to the ADHD-positive comparison group. Regarding parent ratings of hyperactivity and impulsivity, the CHD group was significantly lower than the ADHD-positive controls (P = 0.024) but greater than the ADHD-negative controls (P < 0.001). CONCLUSION: ADHD symptoms are more prevalent in children with CHD. Parent ratings of inattention and hyperactivity symptoms in CHD patients are similar to ratings in children diagnosed with ADHD. There is a trend towards a greater prevalence of inattention symptoms in patients with cyanosis or single ventricle physiology.

The Time Course of Effect of Multilayer-Release Methylphenidate Hydrochloride Capsules: A Randomized, Double-Blind Study of Adults With ADHD in a Simulated Adult Workplace Environment.

Objective: The aim of this study is to assess the onset and duration of efficacy of multilayer-release methylphenidate (PRC-063) over 16 hr compared with placebo in adults with ADHD using the simulated adult workplace environment. Method: After dose-optimization with PRC-063, participants entered a double-blind, placebo-controlled, crossover phase. Primary outcome measure was the Permanent Product Measure of Performance (PERMP) total score measured pre-dose and from 1 to 16 hr post-dose. Results: Of the 59 randomized participants, 45 participants completed the study. While receiving PRC-063, adults had greater mean PERMP total scores across all time points compared with placebo (268.7 ± 11.24 vs. 255.6 ± 10.87; p = .0064). Common adverse events were decreased appetite, headache, and insomnia. There was no significant impact on overall sleep quality (p = .9542). Conclusion: PRC-063 significantly improved PERMP scores with an onset within 1 hr post-dose, and maintained improvement throughout the 16 hr post-dose study period compared with placebo in adults with ADHD.

Safety and Efficacy of Centanafadine Sustained-Release in Adults With Attention-Deficit Hyperactivity Disorder: Results of Phase 2 Studies.

PURPOSE: Two phase 2 studies evaluated the efficacy and tolerability of centanafadine sustained-release (SR) for adults with attention-deficit/hyperactivity disorder (ADHD). PATIENTS AND METHODS: In a phase 2a, flexible-dose, single-blind study, 41 male patients (aged 18‒55 years) with a diagnosis of ADHD (based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) were titrated with centanafadine-SR 200‒300, 400, or 500 mg/d for 2 weeks, and then were treated with the titrated dose for 2 weeks. In a phase 2b, randomized, double-blind, placebo-controlled, crossover study, 85 male and female patients (aged 18‒60 years) with a diagnosis of ADHD (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) were titrated to target doses of centanafadine-SR 400, 500, 600, or 800 mg/d over the course of 1 week, and then received their titrated dose for 3 weeks. The primary outcome in both studies was mean total ADHD Rating Scale-IV (ADHD-RS-IV) score. RESULTS: In the phase 2a study, mean ADHD-RS-IV total score decreased by 21.41 (standard deviation 10.74) from the start of active centanafadine-SR treatment to the end of week 4 (P<0.001). In the phase 2b study, centanafadine-SR treatment resulted in a statistically significant improvement in ADHD-RS-IV from baseline to week 3 compared with placebo (least-squares mean -16.5 vs -8.4; P<0.001; effect size 0.66), with significant efficacy demonstrated as early as week 1. Centanafadine-SR was generally well tolerated at doses ≤400 mg. Most treatment-emergent adverse events (TEAEs) were mild or moderate; decreased appetite, headache, and nausea were the most frequently reported. In the 2 studies, 13 of 120 patients discontinued centanafadine-SR due to TEAEs; however, only 1 patient who received ≤400 mg discontinued due to a TEAE. No serious TEAEs were reported at any dose. CONCLUSION: These results support the continued development of centanafadine-SR at doses up to 400 mg/d.

Evaluating dopamine reward pathway in ADHD: clinical implications.

CONTEXT: Attention-deficit/hyperactivity disorder (ADHD)--characterized by symptoms of inattention and hyperactivity-impulsivity--is the most prevalent childhood psychiatric disorder that frequently persists into adulthood, and there is increasing evidence of reward-motivation deficits in this disorder. OBJECTIVE: To evaluate biological bases that might underlie a reward/motivation deficit by imaging key components of the brain dopamine reward pathway (mesoaccumbens). DESIGN, SETTING, AND PARTICIPANTS: We used positron emission tomography to measure dopamine synaptic markers (transporters and D(2)/D(3) receptors) in 53 nonmedicated adults with ADHD and 44 healthy controls between 2001-2009 at Brookhaven National Laboratory. MAIN OUTCOME MEASURES: We measured specific binding of positron emission tomographic radioligands for dopamine transporters (DAT) using [(11)C]cocaine and for D(2)/D(3) receptors using [(11)C]raclopride, quantified as binding potential (distribution volume ratio -1). RESULTS: For both ligands, statistical parametric mapping showed that specific binding was lower in ADHD than in controls (threshold for significance set at P < .005) in regions of the dopamine reward pathway in the left side of the brain. Region-of-interest analyses corroborated these findings. The mean (95% confidence interval [CI] of mean difference) for DAT in the nucleus accumbens for controls was 0.71 vs 0.63 for those with ADHD (95% CI, 0.03-0.13, P = .004) and in the midbrain for controls was 0.16 vs 0.09 for those with ADHD (95% CI, 0.03-0.12; P < or = .001); for D(2)/D(3) receptors, the mean accumbens for controls was 2.85 vs 2.68 for those with ADHD (95% CI, 0.06-0.30, P = .004); and in the midbrain, it was for controls 0.28 vs 0.18 for those with ADHD (95% CI, 0.02-0.17, P = .01). The analysis also corroborated differences in the left caudate: the mean DAT for controls was 0.66 vs 0.53 for those with ADHD (95% CI, 0.04-0.22; P = .003) and the mean D(2)/D(3) for controls was 2.80 vs 2.47 for those with ADHD (95% CI, 0.10-0.56; P = .005) and differences in D(2)/D(3) in the hypothalamic region, with controls having a mean of 0.12 vs 0.05 for those with ADHD (95% CI, 0.02-0.12; P = .004). Ratings of attention correlated with D(2)/D(3) in the accumbens (r = 0.35; 95% CI, 0.15-0.52; P = .001), midbrain (r = 0.35; 95% CI, 0.14-0.52; P = .001), caudate (r = 0.32; 95% CI, 0.11-0.50; P = .003), and hypothalamic (r = 0.31; CI, 0.10-0.49; P = .003) regions and with DAT in the midbrain (r = 0.37; 95% CI, 0.16-0.53; P < or = .001). CONCLUSION: A reduction in dopamine synaptic markers associated with symptoms of inattention was shown in the dopamine reward pathway of participants with ADHD.

Long-term safety of stimulant medications used to treat children with ADHD.

Attention-deficit/hyperactivity disorder (ADHD) is a common mental health condition that affects children, adolescents, and adults. Because it is a chronic condition and typically requires effective treatment for several years or more, information on the benefits and risks of long-term pharmacotherapy for ADHD is vital to clinicians. This article reviews the emerging literature on the safety of long-term stimulant medications in ADHD-the most commonly prescribed medications for this condition. Common side effects, including cardiovascular effects, growth effects, and tics, are discussed, as well as treatment of children younger than age 6 and evidence of carcinogenic and reproductive effects.

A Double-Blind, Placebo-Controlled, Phase II Study to Determine the Efficacy, Safety, Tolerability and Pharmacokinetics of a Controlled Release (CR) Formulation of Mazindol in Adults with DSM-5 Attention-Deficit/Hyperactivity Disorder (ADHD).

BACKGROUND: Mazindol is under investigation for the treatment of attention-deficit/hyperactivity disorder (ADHD) because of its alertness-enhancing properties. A novel controlled-release (CR) formulation of mazindol was developed to allow once-daily dosing. OBJECTIVE: The aim of this study was to evaluate the efficacy of mazindol CR in adults with ADHD. DESIGN: We conducted a randomized, double-blind, placebo-controlled 6-week trial. METHODS: Subjects diagnosed with ADHD using the Mini-International Neuropsychiatric Structured Interview (MINI) and with an ADHD Rating Scale, Diagnostic and Statistical Manual of Mental Disorders 5th Edition (ADHD-RS-DSM5) score ≥ 28 were randomized to receive placebo or 1-3 mg/day of mazindol for 6 weeks. The primary endpoint was the reduction from baseline in the ADHD-RS-DSM5 score on Day 42. Secondary endpoints were response rates defined by change in ADHD-RS-DSM5 (≥ 30 or ≥ 50% reduction) and dichotomized Clinical Global Impression-Improvement (CGI-I) score (1 or 2). An exploratory endpoint of functional impairment, as measured by the Target Impairment Scale, examined individualized deficits in specific settings. Safety, tolerability, and pharmacokinetics were assessed. RESULTS: Eighty-five participants were randomized (n = 43 active, 42 placebo); 75 completed. Weekly ADHD-RS-DSM5 measurements after mazindol differed from placebo beginning at Day 7, with a least squares mean difference (active-placebo) of - 13.2 at Day 42 and an effect size of 1.09. For the 30% or more reduction in ADHD-RS-DSM5 (minimal response), a significant difference (active-placebo) was seen starting at Day 7 and continuing to Day 42. For the CGI-I (1 or 2) and for the 50% or more reduction in ADHD-RS-DSM5 (measures of excellent response), the differences began at Day 14 and continued to Day 42. Functional impairment was significantly different in the proportion achieving at least a 50% reduction in target impairment score (42.9% mazindol vs 11.9% placebo) by Day 42. Dry mouth, nausea, fatigue, heart rate (HR) increased, decreased appetite, and constipation were more prevalent for mazindol versus placebo. Overall, mazindol CR had minimal effects on blood pressure and small effects on HR. CONCLUSION: Mazindol CR was efficacious in the treatment of adults with ADHD, with a large effect size, and was well tolerated, supporting the progression to phase III. (Clinicaltrials.gov Registration No. NCT02808104).

Pharmacokinetics of methylphenidate in preschoolers with attention-deficit/hyperactivity disorder.

OBJECTIVE: The aim of this study was to compare the pharmacokinetics of immediate-release methylphenidate (MPH) in preschool and school-aged children with attention-deficit/hyperactivity disorder (ADHD). METHODS: Preschool children 4-5 years (n = 14) and school-aged children 6-8 years (n = 9) with diagnoses of ADHD were titrated to an effective dose of MPH based on parent, teacher, and clinician ratings in a protocol specified by the Preschoolers with ADHD Treatment Study (PATS) and then attended a laboratory school where the single morning dose of immediate release MPH was administered. Blood samples for measurement of MPH concentrations were obtained predose, and at 1, 2, 4, and 6 hours postdose. A nonlinear model was used to derive three pharmacokinetic (PK) values for analysis: Peak plasma concentration (C(max)), half-life (t(1/2)), and clearance (CL). RESULTS: The two groups did not differ in the mean mg dose of MPH (p = 0.33), or in the weight-adjusted mg/kg dose (p = 0.20). Dose-normalized C(max) was significantly higher (p = 0.003), and clearance was significantly slower (p = 0.0002) in preschool than in school-aged children. CONCLUSIONS: In this sample, age significantly affected absorption and metabolism of MPH, so that preschool children had greater exposure than school-aged children to the same weight-adjusted dose. These data suggest additional studies should be performed to characterize age-related differences in PK properties of MPH that may inform practitioners about dosing strategies based on the age and size of children being treated.

Methylphenidate effects on functional outcomes in the Preschoolers with Attention-Deficit/Hyperactivity Disorder Treatment Study (PATS).

OBJECTIVE: The purpose of this study was to examine the effects of methylphenidate (MPH) on functional outcomes, including children's social skills, classroom behavior, emotional status, and parenting stress, during the 4-week, double-blind placebo controlled phase of the Preschoolers with Attention Deficit/Hyperactivity Disorder (ADHD) Treatment Study (PATS). METHODS: A total of 114 preschoolers who had improved with acute MPH treatment, were randomized to their best MPH dose (M = 14.22 mg/day; n = 63) or placebo (PL; n = 51). Assessments included the Clinical Global Impression-Severity (CGI-S), parent and teacher versions of the Strengths and Weaknesses of ADHD-Symptoms and Normal Behaviors (SWAN), Social Competence Scale (SCS), Social Skills Rating System (SSRS), and Early Childhood Inventory (ECI), and Parenting Stress Index (PSI). RESULTS: Medication effects varied by informant and outcome measure. Parent measures and teacher SWAN scores did not differentially improve with MPH. Parent-rated depression (p < 0.02) and dysthymia (p < 0.001) on the ECI worsened with MPH, but scores were not in the clinical range. Significant medication effects were found on clinician CGI-S (p < 0.0001) and teacher social competence ratings (SCS, p < 0.03). CONCLUSIONS: Preschoolers with ADHD treated with MPH for 4 weeks improve in some aspects of functioning. Additional improvements might require longer treatment, higher doses, and/or intensive behavioral treatment in combination with medication.

Effectiveness of methylphenidate in the 10-month continuation phase of the Preschoolers with Attention-Deficit/Hyperactivity Disorder Treatment Study (PATS).

OBJECTIVE: The aim of this study was to examine immediate-release methylphenidate effectiveness during the 10-month open-label continuation phase of the Preschoolers with Attention-Deficit/Hyperactivity Disorder (ADHD) Treatment Study (PATS). METHODS: One hundred and forty preschoolers with ADHD, who had improved with acute immediate-release methylphenidate (IR-MPH) treatment, entered a 10-month, open-label medication maintenance at six sites. Assessments included the Clinical Global Impression-Severity (CGI-S), CGI-Improvement (CGI-I), Children's Global Assessment Scale (C-GAS), Swanson, Nolan, and Pelham Questionnaire (SNAP), Scale Strengths and Weaknesses of ADHD-Symptoms and Normal Behaviors (SWAN), Social Competence Scale, Social Skills Rating System (SSRS), and Parenting Stress Index-Short Form (PSI-SF). RESULTS: For the 95 children who completed the 10-month treatment, improvement occurred on the CGI-S (p = 0.02), CGI-I (p < 0.01), C-GAS (p = 0.001), and SSRS (p = 0.01). SNAP and SWAN scores remained stable. Forty five children discontinued: 7 for adverse effects, 7 for behavior worsening, 7 for switching to long-acting stimulants, 3 for inadequate benefit, and 21 for other reasons. The mean MPH dose increased from 14.04 mg/day +/- SD 7.57 (0.71 +/- 0.38 mg/kg per day) at month 1 to 19.98 mg/day +/- 9.56 (0.92 +/- 0.40 mg/kg per day) at month 10. CONCLUSIONS: With careful monitoring and gradual medication dose increase, most preschoolers with ADHD maintained improvement during long-term IR-MPH treatment. There was substantial variability in effective and tolerated dosing.

Factor structure of parent- and teacher-rated attention-deficit/hyperactivity disorder symptoms in the Preschoolers with Attention-Deficit/Hyperactivity Disorder Treatment Study (PATS).

OBJECTIVE: This study examines one-, two-, and three-factor models of attention-deficit/hyperactivity disorder (ADHD) using the existing 18 Diagnostic and Statistical Manual of Mental Disorder, 4th edition (DSM-IV) symptoms in a sample of symptomatic preschoolers. METHODS: Parent and/or teacher ratings of DSM-IV symptoms were obtained for 532 children (aged 3-5.5) who were screened for the Preschool ADHD Treatment Study (PATS). Confirmatory factor analysis (CFA) using symptoms identified on the Conners' Parent and Teacher Rating Scales was conducted to assess a two-factor model representing the DSM-IV dimensions of inattention (IN) and hyperactivity/impulsivity (H/I), a three-factor model reflecting inattention, hyperactivity, and impulsivity, and a single-factor model of all ADHD symptoms. Exploratory factor analysis (EFA) was subsequently used to examine the latent structure of the data. RESULTS: For parent ratings, the two-factor and three-factor models were marginally acceptable according to several widely used fit indices, whereas the one-factor model failed to meet minimum thresholds for goodness-of-fit. For teachers, none of the models was a solid fit for the data. Maximum likelihood EFAs resulted in satisfactory two and three-factor models for both parents and teachers, although all models contained several moderate cross loadings. Factor loadings were generally concordant with those published for older children and community-based samples. CONCLUSION: ADHD subtypes according to current DSM-IV specifications may not be the best descriptors of the disorder in the preschool age group.

Parent versus teacher ratings of attention-deficit/hyperactivity disorder symptoms in the Preschoolers with Attention-Deficit/Hyperactivity Disorder Treatment Study (PATS).

OBJECTIVE: To assess parent-teacher concordance on ratings of DSM-IV symptoms of attention-deficit/hyperactivity disorder (ADHD) in a sample of preschool children referred for an ADHD treatment study. METHODS: Parent and teacher symptom ratings were compared for 452 children aged 3-5 years. Agreement was calculated using Pearson correlations, Cohen's kappa, and conditional probabilities. RESULTS: The correlations between parent and teacher ratings were low for both Inattentive (r = .24) and Hyperactive-Impulsive (r = .26) symptom domains, with individual symptoms ranging from .01-.28. Kappa values for specific symptoms were even lower. Conditional probabilities suggest that teachers are only moderately likely to agree with parents on the presence or absence of symptoms. Parents were quite likely to agree with teachers' endorsement of symptoms, but much less likely to agree when teachers indicated that a symptom was not present. CONCLUSIONS: Results provide important data regarding base rates and concordance rates in this age group and support the hypothesis that preschool-aged children at risk for ADHD exhibit significant differences in behavior patterns across settings. Obtaining ratings from multiple informants is therefore considered critical for obtaining a full picture of young children's functioning.

Effects of source of DNA on genotyping success rates and allele percentages in the Preschoolers with Attention-Deficit/Hyperactivity Disorder Treatment Study (PATS).

OBJECTIVE: In children diagnosed with attention-deficit/hyperactivity disorder (ADHD) and their parents, who were participants of the Preschool ADHD Treatment Study (PATS), we assessed the effect of source of DNA (from buccal or blood cells) on the genotyping success rate and allele percentages for the five polymorphisms in three candidate genes (DAT1, DRD4, and SNAP 25) investigated in the PATS pharmacogenetic study of response to stimulant medication. METHOD: At baseline assessment, 241 individuals (113 probands and 128 parents) consented to participate; 144 individuals (52 probands and 92 parents) provided blood samples from venipuncture, and 97 individuals (61 probands and 36 parents) provided buccal samples from cheek swab as specimens for isolation of DNA. Three types of polymorphisms-variable number of tandem repeat (VNTR) polymorphism, tandem duplication polymorphism (TDP), and single nucleotide polymorphism (SNP)-were evaluated, including the DRD4 gene 48-bp VNTR in exon III, the DAT1 gene 40-bp VNTR in 3'-untranslated region, the DRD4 gene TDP 120-bp duplication in the promoter region, the SNAP-25 gene TC-1069 SNP, and the SNAP-25 gene TG-1065 SNP. Standard procedures were used to genotype individuals for each of these five polymorphisms. RESULTS: Using the methods available in 2004, the genotyping success rate was on the average much greater for DNA from blood cells than buccal cells (e.g., 91% vs. 54% in probands). For some polymorphisms (DRD4-VNTR, DRD4-TDP, and SNAP25-TC SNP), allele proportion also varied by blood versus buccal source of DNA (e.g., 26.5% vs. 18.6% for the 7-repeat allele of the DRD4 gene). CONCLUSIONS: The much lower success rate for genotyping based on DNA from buccal than blood cells is likely due to the quality of DNA derived from these two sources. The observed source differences in allele proportion may be due to self-selection related to choice of how specimens were collected (from cheek swab or venipuncture), or to a selective detection of some alleles based on differences in DNA quality.

Clinical presentation of attention-deficit/hyperactivity disorder in preschool children: the Preschoolers with Attention-Deficit/Hyperactivity Disorder Treatment Study (PATS).

OBJECTIVE: The aim of this study was to describe the clinical presentation of preschoolers diagnosed with moderate to severe attention-deficit/hyperactivity disorder (ADHD) recruited for the multisite Preschool ADHD Treatment Study (PATS). The diagnosis and evaluation process will also be described. METHOD: A comprehensive multidimensional, multi-informant assessment protocol was implemented including the semistructured PATS Diagnostic Interview. Parent and teacher-report measures were used to supplement information from interviews. Consensus agreement by a cross-site panel on each participant's diagnoses was required. Analyses were conducted to describe the sample and to test associations between ADHD severity and demographic and clinical variables. RESULTS: The assessment protocol identified 303 preschoolers (3-5.5 years) with moderate to severe ADHD Hyperactive/Impulsive or Combined type. The majority of participants (n = 211, 69.6%) experienced co-morbid disorders, with oppositional defiant disorder, communication disorders, and anxiety disorders being the most common. Participants with co-morbid communication disorders were found to be more anxious and depressed. ADHD severity was found to correlate with more internalizing difficulties and lower functioning. Although boys and girls had similar symptom presentations, younger children had significantly higher ADHD severity. CONCLUSIONS: Preschoolers with moderate to severe ADHD experience high co-morbidity and impairment, which have implications for both assessment and treatment.

Comorbidity moderates response to methylphenidate in the Preschoolers with Attention-Deficit/Hyperactivity Disorder Treatment Study (PATS).

OBJECTIVE: The aim of this study was to examine whether demographic or pretreatment clinical and social characteristics influenced the response to methylphenidate (MPH) in the Preschoolers with ADHD Treatment Study (PATS). METHODS: Exploratory moderator analyses were conducted on the efficacy data from the PATS 5-week, double-blind, placebo-controlled six-site titration trial. Children (N = 165, age 3-5.5 years) were randomized to 1 week each of four MPH doses (1.25, 2.5, 5, and 7.5 mg) and placebo administered three times per day (t.i.d.). We assessed the fixed effects on the average slope in the regression outcome on moderators, weight-adjusted dose, and the moderator-by-dose interaction using SAS PROC GENMOD. RESULTS: A significant interaction effect was found for a number of co-morbid disorders diagnosed in the preschoolers at baseline (p = 0.005). Preschoolers with three or more co-morbid disorders did not respond to MPH (Cohen's d at 7.5 mg dose relative to placebo = -0.37) compared to a significant response in the preschoolers with 0, 1, or 2 co-morbid disorders (Cohen's d = 0.89, 1.00, and 0.56, respectively). Preschoolers with more co-morbidity were found to have more family adversity. No significant interaction effect was found with the other variables. CONCLUSIONS: In preschoolers with ADHD, the presence of no or one co-morbid disorder (primarily oppositional defiant disorder) predicted a large treatment response at the same level as has been found in school-aged children, and two co-morbid disorders predicted moderate treatment response; whereas the presence of three or more co-morbid disorders predicted no treatment response to MPH.

Safety and tolerability of methylphenidate in preschool children with ADHD.

OBJECTIVE: To report on the safety and tolerability of methylphenidate (MPH) 3- to 5-year-old children with attention-deficit/hyperactivity disorder (ADHD) during 1 year of treatment. METHOD: Exactly 183 children (3-5 years old) entered a treatment study of MPH, consisting of a 1-week open-label lead-in (n=183); a 5-week placebo-controlled, double-blind phase (n=165); a 5-week double-blind, parallel phase (n=114); and 10 months of open-label maintenance (n=140 entered, 95 completed). Mean total daily MPH doses rose from the titration trial best dose, 14.1 (+/-8.1) mg/day, to 20.5 (+/-9.7) mg/day mean total daily dose at the end of maintenance. Pulse, blood pressure, and the presence of treatment emergent adverse events (AEs), parent and teacher AE ratings, and vital signs were recorded in each phase. RESULTS: Thirty percent of parents spontaneously reported moderate to severe AEs in all study phases after baseline. These included emotional outbursts, difficulty falling asleep, repetitive behaviors/thoughts, appetite decrease, and irritability. During titration, decreased appetite (chi=5.4, p<.03), trouble sleeping (chi=5.4, p<.03), and weight loss (chi=4.0, p<.05) occurred statistically more often on MPH than on placebo. During maintenance, trouble sleeping and appetite loss persisted and other MPH-related AEs decreased. There were transient, one-time pulse and blood pressure elevations in five children. Twenty-one children (11%) discontinued because of drug-attributed AEs. CONCLUSIONS: Eleven percent of preschoolers discontinued treatment because of intolerable MPH AEs. Of the serious AEs reported, one occurred in baseline, two in lead-in, three in titration, one in parallel, and one in maintenance. Only one was possibly related to MPH.

Efficacy and safety of immediate-release methylphenidate treatment for preschoolers with ADHD.

OBJECTIVE: The Preschool ADHD Treatment Study (PATS) was a NIMH-funded, six-center, randomized, controlled trial to determine the efficacy and safety of immediate-release methylphenidate (MPH-IR), given t.i.d. to children ages 3 to 5.5 years with attention-deficit/hyperactivity disorder (ADHD). METHOD: The 8-phase, 70-week PATS protocol included two double-blind, controlled phases, a crossover-titration trial followed by a placebo-controlled parallel trial. The crossover-titration phase's primary efficacy measure was a combined score from the Swanson, Kotkin, Atkins, M-Flynn, and Pelham (SKAMP) plus the Conners, Loney, and Milich (CLAM) rating scales; the parallel phase's primary outcome measure was excellent response, based on composite scores on the Swanson, Nolan, and Pelham (SNAP) rating scale. RESULTS: Of 303 preschoolers enrolled, 165 were randomized into the titration trial. Compared with placebo, significant decreases in ADHD symptoms were found on MPH at 2.5 mg (p<.01), 5 mg (p<.001), and 7.5 mg (p<.001) t.i.d. doses, but not for 1.25 mg (p<.06). The mean optimal MPH total daily dose for the entire group was 14.2 +/- 8.1 mg/day (0.7+/-0.4 mg/kg/day). For the preschoolers (n=114) later randomized into the parallel phase, only 21% on best-dose MPH and 13% on placebo achieved MTA-defined categorical criterion for remission set for school-age children with ADHD. CONCLUSIONS: MPH-IR, delivered in 2.5-, 5-, and 7.5-mg doses t.i.d., produced significant reductions on ADHD symptom scales in preschoolers compared to placebo, although effect sizes (0.4-0.8) were smaller than those cited for school-age children on the same medication.

Stimulant-related reductions of growth rates in the PATS.

OBJECTIVE: To investigate growth of children with attention-deficit/hyperactivity disorder (ADHD) in the Preschool ADHD Treatment Study (PATS) before and after initiation of treatment with methylphenidate at titrated doses (average, 14.2 mg/day) administered three times daily, 7 days/week for asymptotically equal to1 year. METHOD: The heights and weights of 140 children with ADHD were measured up to 29 times in the PATS protocol, starting at an average age of 4.4 years. The relationship between standard (z) scores and time on medication was examined using mixed-effect regression to estimate change in relative size (slope). RESULTS: Average relative size at baseline was significantly (p<.0001) greater than zero for z height (+0.45) and z weight (+0.78), indicating greater than expected height (by 2.04 cm) and weight (by 1.78 kg). During treatment, slopes were significantly (p<.0001) less than zero for z height (-0.304/yr) and z weight (-0.530/yr), indicating reduction of growth rates. For 95 children who remained on medication, annual growth rates were 20.3% less than expected for height (5.41 cm/yr-6.79 cm/yr=-1.38 cm/yr) and 55.2% for weight (1.07 kg/yr-2.39 kg/yr=-1.32 kg/yr). CONCLUSIONS: Risks of reduced growth rates should be balanced against expected benefits when preschool-age children are treated with stimulant medication.

Rationale, design, and methods of the Preschool ADHD Treatment Study (PATS).

OBJECTIVE: To describe the rationale and design of the Preschool ADHD Treatment Study (PATS). METHOD: PATS was a National Institutes of Mental Health-funded, multicenter, randomized, efficacy trial designed to evaluate the short-term (5 weeks) efficacy and long-term (40 weeks) safety of methylphenidate (MPH) in preschoolers with attention-deficit/hyperactivity disorder (ADHD). Three hundred three subjects ages 3 to 5.5 years old who met criteria for a primary DSM-IV diagnosis of ADHD entered the trial. Subjects participated in an 8-phase, 70-week trial that included screening, parent training, baseline, open-label safety lead-in, double-blind crossover titration, double-blind parallel efficacy, open-label maintenance, and double-blind discontinuation. Medication response was assessed during the crossover titration phase using a combination of parent and teacher ratings. Special ethical considerations throughout the trial warranted a number of design changes. RESULTS: This report describes the design of this trial, the rationale for reevaluation and modification of the design, and the methods used to conduct the trial. CONCLUSIONS: The PATS adds to a limited literature and improves our understanding of the safety and efficacy of MPH in the treatment of preschoolers with ADHD, but changes in the design and problems in implementation of this study impose some specific limitations that need to be addressed in future studies.

Pharmacogenetics of methylphenidate response in preschoolers with ADHD.

OBJECTIVE: The authors explored genetic moderators of symptom reduction and side effects in methylphenidate-treated preschool-age children diagnosed with attention-deficit/hyperactivity disorder (ADHD). METHOD: DNA was isolated from 81 subjects in a double-blind, placebo-controlled, crossover methylphenidate titration. Parents and teachers completed ADHD symptom scales and side effect ratings for each of five randomly administered weekly conditions that included immediate-release methylphenidate 1.25, 2.5, 5.0, 7.5 mg and placebo given three times daily. Candidate genes hypothesized to influence stimulant effects or individual risks for ADHD were genotyped. RESULTS: Although the primary analysis did not indicate significant genetic effects, secondary analyses revealed associations between symptom response and variants at the dopamine receptor (DRD4) promoter (p=.05) and synaptosomal-associated protein 25 (SNAP25) allelesT1065G (p=.03) andT1069C (p=.05). SNAP25 variants were also associated with tics (p=.02), buccal-lingual movements (p=.01), and irritability (p=04). DRD4 variants were also associated with picking (p=.03). Increasing dose predicted irritability (p=.05) and social withdrawal (p=.03) with DRD4 variants. There were no significant effects for the dopamine transporter (DAT1). CONCLUSIONS: Emerging evidence suggests the potential for understanding the individual variability of response to and side effects of ADHD medications from the study of genetics, although additional research is required before these findings are proven to have clinical utility.