The ecological validity of delay aversion and response inhibition as measures of impulsivity in AD/HD: a supplement to the NIMH multimodal treatment study of AD/HD.

Impulsivity is a primary symptom of the combined type of Attention Deficit/Hyperactivity Disorder (AD/HD). The Stop Signal Paradigm is premised upon a primary deficit in inhibitory control in AD/HD, whereas the Delay Aversion Hypothesis, by contrast, conceptualizes impulsivity in AD/HD, not as an inability to inhibit a response, but rather as a choice to avoid delay. This study compared the ecological validity of the Stop Signal Task (SST) and Choice-Delay Task (C-DT) measure of delay aversion, with respect to their relative utility in discriminating AD/HD children from normal control participants, and their correlations with classroom observations and with ratings of impulsivity and other core AD/HD symptoms on the Conners and SNAP-IV checklists. The tasks exhibited modest discriminant validity when used individually and excellent discriminant validity when used in combination. The C-DT correlated with teacher ratings of impulsivity, hyperactivity, and conduct problems, and with observations of gross motor activity, physical aggression, and an AD/HD composite score. The SST correlated with the observations only. These results suggest that delay aversion is associated with a broad range of AD/HD characteristics whereas inhibitory failure seems to tap a more discrete dimension of executive control.

Tailored psychosocial treatments for ADHD: the search for a good fit.

Commented on the article "What Does the MTA Study Tell Us About Effective Psychosocial Treatment for ADHD?" by Greene and Ablon (this issue). In this article, these authors note that the Multimodal Treatment Study (MTA) did not focus on or provide information about how to match treatment to the needs of the individual child. They contend that cognitive-behavioral treatment (CBT), which was not included in the MTA, can facilitate treatment tailoring if delivered appropriately. The authors offer several suggestions regarding how CBT can be structured to meet the needs of each child. This commentary points out that the MTA included psychosocial treatments with established rather than potential efficacy. Systematic studies are needed to determine whether the suggestions offered by Greene and Ablon have clinical utility. Matching treatment to the needs of individual patients remains the overarching goal of those interested in idiographic approaches to treatment. However, efforts to inform on treatment tailoring involve complex design and needs assessment methodologies. Several suggestions are offered regarding the technology of treatment tailoring. These include the use of goal attainment scaling to identify and evaluate individualized outcome measures and the use of hybrid efficacy-effectiveness designs to assess the impact of treatment preference on outcome.

Findings from the NIMH Multimodal Treatment Study of ADHD (MTA): implications and applications for primary care providers.

In 1992, the National Institute of Mental Health and 6 teams of investigators began a multisite clinical trial, the Multimodal Treatment of Attention-Deficit Hyperactivity Disorder (MTA) study. Five hundred seventy-nine children were randomly assigned to either routine community care (CC) or one of three study-delivered treatments, all lasting 14 months. The three MTA treatments-monthly medication management (usually methylphenidate) following weekly titration (MedMgt), intensive behavioral treatment (Beh), and the combination (Comb)-were designed to reflect known best practices within each treatment approach. Children were assessed at four time points in multiple outcome. Results indicated that Comb and MedMgt interventions were substantially superior to Beh and CC interventions for attention-deficit hyperactivity disorder symptoms. For other functioning domains (social skills, academics, parent-child relations, oppositional behavior, anxiety/depression), results suggested slight advantages of Comb over single treatments (MedMgt, Beh) and community care. High quality medication treatment characterized by careful yet adequate dosing, three times daily methylphenidate administration, monthly follow-up visits, and communication with schools conveyed substantial benefits to those children that received it. In contrast to the overall study findings that showed the largest benefits for high quality medication management (regardless of whether given in the MedMgt or Comb group), secondary analyses revealed that Comb had a significant incremental effect over MedMgt (with a small effect size for this comparison) when categorical indicators of excellent response and when composite outcome measures were used. In addition, children with parent-defined comorbid anxiety disorders, particularly those with overlapping disruptive disorder comorbidities, showed preferential benefits to the Beh and Comb interventions. Parental attitudes and disciplinary practices appeared to mediate improved response to the Beh and Comb interventions.

ADHD comorbidity findings from the MTA study: comparing comorbid subgroups.

OBJECTIVES: Previous research has been inconclusive whether attention-deficit/hyperactivity disorder (ADHD), when comorbid with disruptive disorders (oppositional defiant disorder [ODD] or conduct disorder [CD]), with the internalizing disorders (anxiety and/or depression), or with both, should constitute separate clinical entities. Determination of the clinical significance of potential ADHD + internalizing disorder or ADHD + ODD/CD syndromes could yield better diagnostic decision-making, treatment planning, and treatment outcomes. METHOD: Drawing upon cross-sectional and longitudinal information from 579 children (aged 7-9.9 years) with ADHD participating in the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA), investigators applied validational criteria to compare ADHD subjects with and without comorbid internalizing disorders and ODD/CD. RESULTS: Substantial evidence of main effects of internalizing and externalizing comorbid disorders was found. Moderate evidence of interactions of parent-reported anxiety and ODD/CD status were noted on response to treatment, indicating that children with ADHD and anxiety disorders (but no ODD/CD) were likely to respond equally well to the MTA behavioral and medication treatments. Children with ADHD-only or ADHD with ODD/CD (but without anxiety disorders) responded best to MTA medication treatments (with or without behavioral treatments), while children with multiple comorbid disorders (anxiety and ODD/CD) responded optimally to combined (medication and behavioral) treatments. CONCLUSIONS: Findings indicate that three clinical profiles, ADHD co-occurring with internalizing disorders (principally parent-reported anxiety disorders) absent any concurrent disruptive disorder (ADHD + ANX), ADHD co-occurring with ODD/CD but no anxiety (ADHD + ODD/CD), and ADHD with both anxiety and ODD/CD (ADHD + ANX + ODD/CD) may be sufficiently distinct to warrant classification as ADHD subtypes different from "pure" ADHD with neither comorbidity. Future clinical, etiological, and genetics research should explore the merits of these three ADHD classification options.

Multimodal treatment of ADHD in the MTA: an alternative outcome analysis.

OBJECTIVE: To conduct a post hoc investigation of the utility of a single composite measure of treatment outcome for the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA) at 14 months postbaseline. BACKGROUND: Examination of multiple measures one at a time in the main MTA intent-to-treat outcome analyses failed to detect a statistically significant advantage of combined treatment (Comb) over medication management (MedMgt). A measure that increases power and precision using a single outcome score may be a useful alternative to multiple outcome measures. METHOD: Factor analysis of baseline scores yielded two "source factors" (parent and teacher) and one "instrument factor" (parent-child interactions). A composite score was created from the average of standardized parent and teacher measures. RESULTS: The composite was internally consistent (alpha = .83), reliable (test-retest over 3 months = 0.86), and correlated 0.61 with clinician global judgments. In an intent-to-treat analysis, Comb was statistically significantly better than all other treatments, with effect sizes ranging from small (0.28) versus MedMgt, to moderately large (0.70) versus a community comparison group. CONCLUSIONS: A composite of ADHD variables may be an important tool in future treatment trials with ADHD and may avoid some of the statistical limitations of multiple measures.

Clinical relevance of the primary findings of the MTA: success rates based on severity of ADHD and ODD symptoms at the end of treatment.

OBJECTIVES: To develop a categorical outcome measure related to clinical decisions and to perform secondary analyses to supplement the primary analyses of the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA). METHOD: End-of-treatment status was summarized by averaging the parent and teacher ratings of attention-deficit/hyperactivity disorder and oppositional defiant disorder symptoms on the Swanson, Nolan, and Pelham, version IV (SNAP-IV) scale, and low symptom-severity ("Just a Little") on this continuous measure was set as a clinical cutoff to form a categorical outcome measure reflecting successful treatment. Three orthogonal comparisons of the treatment groups (combined treatment [Comb], medication management [MedMgt], behavioral treatment [Beh], and community comparison [CC]) evaluated hypotheses about the MTA medication algorithm ("Comb + MedMgt versus Beh + CC"), multimodality superiority ("Comb versus MedMgt"), and psychosocial substitution ("Beh versus CC"). RESULTS: The summary of SNAP-IV ratings across sources and domains increased the precision of measurement by 30%. The secondary analyses of group differences in success rates (Comb = 68%; MedMgt = 56%; Beh = 34%; CC = 25%) confirmed the large effect of the MTA medication algorithm and a smaller effect of multimodality superiority, which was now statistically significant (p < .05). The psychosocial substitution effect remained negligible and nonsignificant. CONCLUSION: These secondary analyses confirm the primary findings and clarify clinical decisions about the choice between multimodal and unimodal treatment with medication.

Methylphenidate dosage for children with ADHD over time under controlled conditions: lessons from the MTA.

OBJECTIVES: To examine the trajectory of methylphenidate (MPH) dosage over time, following a controlled titration, and to ascertain how accurately the titration was able to predict effective long-term treatment in children with attention-deficit/hyperactivity disorder (ADHD). METHOD: Using the 14-month-treatment database of the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA), the outcome of the initial placebo-controlled, double-blind, randomized daily switch titration of MPH was compared with the subsequent maintenance pharmacotherapy. Children received monthly monitoring visits and, when needed, medication adjustments. RESULTS: Of the 198 children for whom MPH was the optimal treatment at titration (mean +/- SD dose: 30.5 +/- 14.2 mg/day), 88% were still taking MPH at the end of maintenance (mean dose 34.4 +/- 13.3 mg/day). Titration-determined dose and end-of-maintenance dose were significantly correlated (r = 0.52-0.68). Children receiving combined pharmacotherapy and behavioral treatment ended maintenance on a lower dose (31.1 +/- 11.7 mg/day) than did children receiving pharmacotherapy only (38.1 +/- 14.2 mg/day). Of the 230 children for whom titration identified an optimal treatment, 17% continued both the assigned medication and dosage throughout maintenance. The mean number of pharmacological changes per child was 2.8 +/- 1.8 (SD), and time to first change was 4.7 months +/- 0.3 (SE). CONCLUSIONS: For most children, initial titration found a dose of MPH in the general range of the effective maintenance dose, but did not prevent the need for subsequent maintenance adjustments. For optimal pharmacological treatment of ADHD, both careful initial titration and ongoing medication management are needed.

Impairment and deportment responses to different methylphenidate doses in children with ADHD: the MTA titration trial.

OBJECTIVE: Results of the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA) were analyzed to determine whether a double-blind, placebo-controlled methylphenidate (MPH) titration trial identified the best MPH dose for each child with attention-deficit/hyperactivity disorder (ADHD). METHOD: Children with ADHD assigned to MTA medication treatment groups (n = 289) underwent a controlled 28-day titration protocol that administered different MPH doses (placebo, low, middle, and high) on successive days. RESULTS: A repeated-measures analysis of variance revealed main effects for MPH dose with greater effects on teacher ratings of impairment and deportment (F3 = 100.6, n = 223, p = .0001; effect sizes 0.8-1.3) than on parent ratings of similar endpoints (F3 = 55.61, n = 253, p = .00001; effect sizes 0.4-0.6). Dose did not interact with period, dose order, comorbid diagnosis, site, or treatment group. CONCLUSIONS: The MTA titration protocol validated the efficacy of weekend MPH dosing and established a total daily dose limit of 35 mg of MPH for children weighing less than 25 kg. It replicated previously reported MPH response rates (77%), distribution of best doses (10-50 mg/day) across subjects, effect sizes on impairment and deportment, as well as dose-related adverse events.

Symptom profiles in children with ADHD: effects of comorbidity and gender.

OBJECTIVE: To examine ratings and objective measures of attention-deficit/hyperactivity disorder (ADHD) symptoms to assess whether ADHD children with and without comorbid conditions have equally high levels of core symptoms and whether symptom profiles differ as a function of comorbidity and gender. METHOD: Four hundred ninety-eight children from the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA) were divided into comorbid groups based on the parent Diagnostic Interview Schedule for Children and assessed via parents' and teachers' Swanson, Nolan, and Pelham (SNAP) ratings and a continuous performance test (CPT). Comorbidity and gender effects were examined using analyses of covariance controlled for age and site. RESULTS: CPT inattention, impulsivity, and dyscontrol errors were high in all ADHD groups. Children with ADHD + oppositional defiant or conduct disorder were rated as more impulsive than inattentive, while children with ADHD + anxiety disorders (ANX) were relatively more inattentive than impulsive. Girls were less impaired than boys on most ratings and several CPT indices, particularly impulsivity, and girls with ADHD + ANX made fewer CPT impulsivity errors than girls with ADHD-only. CONCLUSIONS: Children with ADHD have high levels of core symptoms as measured by rating scales and CPT, irrespective of comorbidity. However, there are important differences in symptomatology as a function of comorbidity and gender.

Psychosocial treatment strategies in the MTA study: rationale, methods, and critical issues in design and implementation.

The Collaborative Multimodal Treatment Study of Children with Attention Deficit Hyperactivity Disorder (ADHD), the MTA, is the first multisite, cooperative agreement treatment study of children, and the largest psychiatric/psychological treatment trial ever conducted by the National Institute of Mental Health. It examines the effectiveness of Medication vs. Psychosocial treatment vs. their combination for treatment of ADHD and compares these experimental arms to each other and to routine community care. In a parallel group design, 579 (male and female) ADHD children, aged 7-9 years, 11 months, were randomly assigned to one of the four experimental arms, and then received 14 months of prescribed treatment (or community care) with periodic reassessments. After delineating the theoretical and empirical rationales for Psychosocial treatment of ADHD, we describe the MTA's Psychosocial Treatment strategy applied to all children in two of the four experimental arms (Psychosocial treatment alone; Combined treatment). Psychosocial treatment consisted of three major components: a Parent Training component, a two-part School Intervention component, and a child treatment component anchored in an intensive Summer Treatment Program. Components were selected based on evidence of treatment efficacy and because they address comprehensive symptom targets, settings, comorbidities, and functional domains. We delineate key conceptual and logistical issues faced by clinical researchers in design and implementation of Psychosocial research with examples of how these issues were addressed in the MTA study.

Anxiety as a predictor and outcome variable in the multimodal treatment study of children with ADHD (MTA).

Initial moderator analyses in the Multimodal Treatment Study of Children with ADHD (MTA) suggested that child anxiety ascertained by parent report on the Diagnostic Interview Schedule for Children 2.3 (DISC Anxiety) differentially moderated the outcome of treatment. Left unanswered were questions regarding the nature of DISC Anxiety, the impact of comorbid conduct problems on the moderating effect of DISC Anxiety, and the clinical significance of DISC Anxiety as a moderator of treatment outcome. Thirty-three percent of MTA subjects met DSM-III-R criteria for an anxiety disorder excluding simple phobias. Of these, two-thirds also met DSM-III-R criteria for comorbid oppositional-defiant or conduct disorder whereas one-third did not, yielding an odds ratio of approximately two for DISC Anxiety, given conduct problems. In this context, exploratory analyses of baseline data suggest that DISC Anxiety may reflect parental attributions regarding child negative affectivity and associated behavior problems (unlike fearfulness), particularly in the area of social interactions, another core component of anxiety that is more typically associated with phobic symptoms. Analyses using hierarchical linear modeling (HLM) indicate that the moderating effect of DISC Anxiety continues to favor the inclusion of psychosocial treatment for anxious ADHD children irrespective of the presence or absence of comorbid conduct problems. This effect, which is clinically meaningful, is confined primarily to parent-reported outcomes involving disruptive behavior, internalizing symptoms, and inattention; and is generally stronger for combined than unimodal treatment. Contravening earlier studies, no adverse effect of anxiety on medication response for core ADHD or other outcomes in anxious or nonanxious ADHD children was demonstrated. When treating ADHD, it is important to search for comorbid anxiety and negative affectivity and to adjust treatment strategies accordingly.

Parenting and family stress treatment outcomes in attention deficit hyperactivity disorder (ADHD): an empirical analysis in the MTA study.

Parenting and family stress treatment outcomes in the MTA study were examined. Male and female (579), 7-9-year-old children with combined type Attention Deficit Hyperactivity Disorder (ADHD), were recruited at six sites around the United States and Canada, and randomly assigned to one of four groups: intensive, multi-faceted behavior therapy program alone (Beh); carefully titrated and monitored medication management strategy alone (MedMgt); a well-integrated combination of the two (Comb); or a community comparison group (CC). Treatment occurred over 14 months, and assessments were taken at baseline, 3, 9, and 14 months. Parenting behavior and family stress were assessed using parent-report and child-report inventories. Results showed that Beh alone, MedMgt alone, and Comb produced significantly greater decreases in a parent-rated measure of negative parenting, Negative/Ineffective Discipline, than did standard community treatment. The three MTA treatments did not differ significantly from each other on this domain. No differences were noted among the four groups on positive parenting or on family stress variables. Results are discussed in terms of the theoretical and empirically documented importance of negative parenting in the symptoms, comorbidities and long-term outcomes of ADHD.

Family processes and treatment outcome in the MTA: negative/ineffective parenting practices in relation to multimodal treatment.

To elucidate processes underlying therapeutic change in a large-scale randomized clinical trial, we examined whether alterations in self-reported parenting practices were associated with the effects of behavioral, medication, or combination treatments on teacher-reported outcomes (disruptive behavior, social skills, internalizing symptoms) in children with attention-deficit hyperactivity disorder (ADHD). Participants were 579 children with Combined-type ADHD, aged 7-9.9 years, in the Multimodal Treatment Study of Children with ADHD (MTA). We uncovered 2 second-order factors of parenting practices, entitled Positive Involvement and Negative/Ineffective Discipline. Although Positive Involvement was not associated with amelioration of the school-based outcome measures, reductions in Negative/Ineffective Discipline mediated improvement in children's social skills at school. For families showing the greatest reductions in Negative/Ineffective Discipline, effects of combined medication plus behavioral treatment were pronounced in relation to regular community care. Furthermore, only in combination treatment (and not in behavioral treatment alone) was decreased Negative/Ineffective Discipline associated with reduction in children's disruptive behavior at school. Here, children in families receiving combination treatment who showed the greatest reductions in Negative/Ineffective Discipline had teacher-reported disruptive behavior that was essentially normalized. Overall, the success of combination treatment for important school-related outcomes appears related to reductions in negative and ineffective parenting practices at home; we discuss problems in interpreting the temporal sequencing of such process-outcome linkages and the means by which multimodal treatment may be mediated by psychosocial processes related to parenting.

Stimulant medications.

OBJECTIVE: To review the short- and long-term safety and efficacy of stimulants for the treatment of children with attention-deficit/hyperactivity disorder (ADHD). METHOD: A Medline search was conducted for both randomized controlled trials and reviews to determine the efficacy and safety of stimulant drugs for treating children with ADHD. Information was obtained on adverse events associated with their use, including their impact on height and weight gain during childhood. Animal data were reviewed for information on tolerance, sensitization, and the impact of high-dose stimulant effects on neurons and on the development of hepatic tumors. Human data on dopamine transporter occupancy by stimulants were also included. RESULTS: Stimulant treatment studies show robust short-term efficacy and a good safety profile. Longer-term studies are few in number but have produced no conclusive evidence that careful therapeutic use of these medications is harmful. CONCLUSION: Current evidence indicates that stimulants show efficacy and safety in studies lasting up to 24 months.

Factors influencing elementary school teachers' ratings of ADHD and ODD behaviors.

Examined factors that influence teachers' ratings of children with either attention deficit hyperactivity disorder (ADHD) or oppositional defiant disorder (ODD). 105 teachers watched 2 videotapes--1 depicting a normal child and the other a child with either ADHD or ODD--and rated each child using 2 different questionnaires. Results indicated that teachers accurately rated the child on the ADHD versus ODD tape as having significantly more inattention and hyperactivity but significantly less oppositionality. However, effect sizes indicated the presence of a unidirectional, negative halo effect of oppositional behaviors on ratings of hyperactivity and inattention. Teachers appeared less biased in their judgments when using a well-operationalized rating scale. Finally, knowledge, education, and experience with children with ADHD generally had no effect on the accuracy of teachers' ratings.

Clinical efficacy of methylphenidate in conduct disorder with and without attention deficit hyperactivity disorder.

BACKGROUND: Stimulants are not considered appropriate for the treatment of children with conduct disorders (CDs). The postulated differences in stimulant effect between children with attention deficit hyperactivity disorder (ADHD) and CD led to the hypothesis that methylphenidate hydrochloride, which is effective in ADHD, would not significantly improve symptoms of CD. METHODS: We randomly assigned 84 children with CD, between the ages of 6 and 15 years, to receive methylphenidate hydrochloride (up to 60 mg/d) or placebo for 5 weeks. Behavior was evaluated by parent, teacher, and clinician reports and by direct classroom observations. Two thirds of the children also met criteria for ADHD. RESULTS: Contrary to prediction, ratings of antisocial behaviors specific to CD were significantly reduced by methylphenidate treatment. The magnitude of methylphenidate effect indicated meaningful clinical benefit. Partialling out severity of ADHD did not alter the significant superiority of methylphenidate on CD ratings specifically (P < .001). CONCLUSIONS: Methylphenidate has short-term positive effects on children and adolescents with CD. Key aspects of antisocial adjustment appear to be treatment responsive. This effect was independent of severity of the children's initial ADHD symptoms.

National Institute of Mental Health Collaborative Multimodal Treatment Study of Children with ADHD (the MTA). Design challenges and choices.

The Collaborative Multimodal Treatment Study of Children with Attention Deficit Hyperactivity Disorder (ADHD), the MTA, is the first child multisite cooperative agreement treatment study of children conducted by the National Institute of Mental Health, Rockville, Md. It examines the long-term effectiveness of medication vs behavioral treatment vs both for treatment of ADHD and compares state-of-the-art treatment with routine community care. In a parallel-groups design, 576 children (age, 7-9 years) with ADHD (96 at each site) are thoroughly assessed and randomized to 4 conditions: (1) medication alone, (2) psychosocial treatment alone, (3) the combination of both, (4) or community comparison. The first 3 groups are treated for 14 months and all are reassessed periodically for 24 months. Designers met the following challenges: framing clinically relevant primary questions; defining the target population; choice, intensity, and integration and combination of treatments for fair comparisons; combining scientific controls and standardization with clinical flexibility; and implementing a controlled clinical trial in a nonclinical setting (school) controlled by others. Innovative solutions included extensive decision algorithms and manualized adaptations of treatments to specific needs.

Hospitalizing the suicidal adolescent: decision-making criteria of psychiatric residents.

OBJECTIVE: The primary purpose of this research is to investigate the criteria used by general psychiatric residents in determining the appropriateness of hospitalization. METHOD: A questionnaire containing 64 vignettes describing adolescent suicide attempts was completed by a sample of 33 residents from a general psychiatry training program. Six variables known to relate to lethality of attempt were systematically varied within the vignettes: gender, depression, conduct disorder/substance abuse, previous attempts, suicidal relative, and family supports. Respondents were asked to judge the appropriateness of hospitalization for each vignette. RESULTS: Hospitalization preference was significantly predicted by all risk factors except for gender, with the presence of depression emerging as the most important predictor of hospitalization. Residents recommended hospitalization more frequently than did experienced child and adolescent clinicians. In comparison with experienced clinicians, residents placed more importance on depression, and less importance on conduct disorder/substance abuse, in making decisions to hospitalize. CONCLUSIONS: Although psychiatric residents use known risk factors for adolescent suicide in assessing need for hospitalization, there was clear support for further training initiatives for psychiatric residents concerning the assessment of suicidal adolescents.

Sleep problems of elementary school children. A community survey.

OBJECTIVE: To examine the prevalence, co-occurrence, and correlates of sleep problems among elementary school children. DESIGN: Survey. SETTING: General community. PARTICIPANTS: The parents of 987 children aged 5 to 12 years completed an anonymous survey distributed in their children's schools. MAIN OUTCOME MEASURES: The survey form asked about background characteristics, children's sleep environment, sleep habits, adult interventions, sleep history, and specific sleep problems. RESULTS: Bedtime resistance was the most prevalent sleep problem (27%). Sleep-onset delays (11.3%), night waking (6.5%), morning wake-up problems (17%), and fatigue complaints (17%) were also common. Among children with sleep-onset problems, 80% displayed bedtime resistance, while 34% of bedtime resisters had onset problems. Onset problems correlated with more fears, night waking, psychiatric and medical conditions, the need for reassurance and caregiver proximity, and history of sleep problems. Bedtime resistance was associated with an inconsistent bedtime and falling asleep away from bed. Those who display delayed sleep onset and bedtime resistance also wake later, suggesting that sleep-phase delays may maintain these problems. CONCLUSIONS: The results confirm bedtime resistance as parents principal sleep-related complaint for this age group but reveal a subgroup more prone to insomnia, night waking, and anxiety-related features. Phase delay findings suggest the importance of limits around wake-up time as well as bedtime. The results highlight the importance of distinctly evaluating bedtime resistance, sleep onset, sleep maintenance, waking, and emotional adjustment.