A Large Underestimate of Formic Acid from Tropical Fires: Constraints from Space-Borne Measurements.

Formic acid (HCOOH) is one of the most abundant carboxylic acids and a dominant source of atmospheric acidity. Recent work indicates a major gap in the HCOOH budget, with atmospheric concentrations much larger than expected from known sources. Here, we employ recent space-based observations from the Tropospheric Emission Spectrometer with the GEOS-Chem atmospheric model to better quantify the HCOOH source from biomass burning, and assess whether fire emissions can help close the large budget gap for this species. The space-based data reveal a severe model HCOOH underestimate most prominent over tropical burning regions, suggesting a major missing source of organic acids from fires. We develop an approach for inferring the fractional fire contribution to ambient HCOOH and find, based on measurements over Africa, that pyrogenic HCOOH:CO enhancement ratios are much higher than expected from direct emissions alone, revealing substantial secondary organic acid production in fire plumes. Current models strongly underestimate (by 10 ± 5 times) the total primary and secondary HCOOH source from African fires. If a 10-fold bias were to extend to fires in other regions, biomass burning could produce 14 Tg/a of HCOOH in the tropics or 16 Tg/a worldwide. However, even such an increase would only represent 15-20% of the total required HCOOH source, implying the existence of other larger missing sources.

HCOOH measurements from space: TES retrieval algorithm and observed global distribution.

Presented is a detailed description of the TES (Tropospheric Emission Spectrometer)-Aura satellite formic acid (HCOOH) retrieval algorithm and initial results quantifying the global distribution of tropospheric HCOOH. The retrieval strategy, including the optimal estimation methodology, spectral microwindows, a priori constraints, and initial guess information, are provided. A comprehensive error and sensitivity analysis is performed in order to characterize the retrieval performance, degrees of freedom for signal, vertical resolution, and limits of detection. These results show that the TES HCOOH retrievals (i) typically provide at best 1.0 pieces of information; (ii) have the most vertical sensitivity in the range from 900 to 600 hPa with ~2 km vertical resolution; (iii) require at least 0.5 ppbv (parts per billion by volume) of HCOOH for detection if thermal contrast is greater than 5 K, and higher concentrations as thermal contrast decreases; and (iv) based on an ensemble of simulated retrievals, are unbiased with a standard deviation of ±0.4 ppbv. The relative spatial distribution of tropospheric HCOOH derived from TES and its associated seasonality are broadly correlated with predictions from a state-of-the-science chemical transport model (GEOS-Chem CTM). However, TES HCOOH is generally higher than is predicted by GEOS-Chem, and this is in agreement with recent work pointing to a large missing source of atmospheric HCOOH. The model bias is especially pronounced in summertime and over biomass burning regions, implicating biogenic emissions and fires as key sources of the missing atmospheric HCOOH in the model.

Quantifying global terrestrial methanol emissions using observations from the TES satellite sensor.

We employ new global space-based measurements of atmospheric methanol from the Tropospheric Emission Spectrometer (TES) with the adjoint of the GEOS-Chem chemical transport model to quantify terrestrial emissions of methanol to the atmosphere. Biogenic methanol emissions in the model are based on version 2.1 of the Model of Emissions of Gases and Aerosols from Nature (MEGANv2.1), using leaf area data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) and GEOS-5 assimilated meteorological fields. We first carry out a pseudo observation test to validate the overall approach, and find that the TES sampling density is sufficient to accurately quantify regional- to continental-scale methanol emissions using this method. A global inversion of two years of TES data yields an optimized annual global surface flux of 122 Tg yr-1 (including biogenic, pyrogenic, and anthropogenic sources), an increase of 60 % from the a priori global flux of 76 Tg yr-1. Global terrestrial methanol emissions are thus nearly 25 % those of isoprene (~540 Tg yr-1), and are comparable to the combined emissions of all anthropogenic volatile organic compounds (~100-200 Tg yr-1). Our a posteriori terrestrial methanol source leads to a strong improvement of the simulation relative to an ensemble of airborne observations, and corroborates two other recent top-down estimates (114-120 Tg yr-1) derived using in situ and space-based measurements. Inversions testing the sensitivity of optimized fluxes to model errors in OH, dry deposition, and oceanic uptake of methanol, as well as to the assumed a priori constraint, lead to global fluxes ranging from 118 to 126 Tg yr-1. The TES data imply a relatively modest revision of model emissions over most of the tropics, but a significant upward revision in midlatitudes, particularly over Europe and North America. We interpret the inversion results in terms of specific source types using the methanol : CO correlations measured by TES, and find that biogenic emissions are overestimated relative to biomass burning and anthropogenic emissions in central Africa and southeastern China, while they are underestimated in regions such as Brazil and the US. Based on our optimized emissions, methanol accounts for > 25 % of the photochemical source of CO and HCHO over many parts of the northern extratropics during springtime, and contributes ~6 % of the global secondary source of those compounds annually.

North American acetone sources determined from tall tower measurements and inverse modeling.

We apply a full year of continuous atmospheric acetone measurements from the University of Minnesota tall tower Trace Gas Observatory (KCMP tall tower; 244 m a.g.l.), with a 0.5° × 0.667° GEOS-Chem nested grid simulation to develop quantitative new constraints on seasonal acetone sources over North America. Biogenic acetone emissions in the model are computed based on the MEGANv2.1 inventory. An inverse analysis of the tall tower observations implies a 37% underestimate of emissions from broadleaf trees, shrubs, and herbaceous plants, and an offsetting 40% overestimate of emissions from needleleaf trees plus secondary production from biogenic precursors. The overall result is a small (16%) model underestimate of the total primary + secondary biogenic acetone source in North America. Our analysis shows that North American primary + secondary anthropogenic acetone sources in the model (based on the EPA NEI 2005 inventory) are accurate to within approximately 20%. An optimized GEOS-Chem simulation incorporating the above findings captures 70% of the variance (R = 0.83) in the hourly measurements at the KCMP tall tower, with minimal bias. The resulting North American acetone source is 11 Tg a-1, including both primary emissions (5.5 Tg a-1) and secondary production (5.5 Tg a-1), and with roughly equal contributions from anthropogenic and biogenic sources. The North American acetone source alone is nearly as large as the total continental volatile organic compound (VOC) source from fossil fuel combustion. Using our optimized source estimates as a baseline, we evaluate the sensitivity of atmospheric acetone and peroxyacetyl nitrate (PAN) to shifts in natural and anthropogenic acetone sources over North America. Increased biogenic acetone emissions due to surface warming are likely to provide a significant offset to any future decrease in anthropogenic acetone emissions, particularly during summer.

Methanol from TES global observations: retrieval algorithm and seasonal and spatial variability.

We present a detailed description of the TES methanol (CH3OH) retrieval algorithm, along with initial global results showing the seasonal and spatial distribution of methanol in the lower troposphere. The full development of the TES methanol retrieval is described, including microwindow selection, error analysis, and the utilization of a priori and initial guess information provided by the GEOS-Chem chemical transport model. Retrieval simulations and a sensitivity analysis using the developed retrieval strategy show that TES: (i) generally provides less than 1.0 piece of information, (ii) is sensitive in the lower troposphere with peak sensitivity typically occurring between ~900-700 hPa (~1-3 km) at a vertical resolution of ~5 km, (iii) has a limit of detectability between 0.5 and 1.0 ppbv Representative Volume Mixing Ratio (RVMR) depending on the atmospheric conditions, corresponding roughly to a profile with a maximum concentration of at least 1 to 2 ppbv, and (iv) in a simulation environment has a mean bias of 0.16 ppbv with a standard deviation of 0.34 ppbv. Applying the newly derived TES retrieval globally and comparing the results with corresponding GEOS-Chem output, we find generally consistent large-scale patterns between the two. However, TES often reveals higher methanol concentrations than simulated in the Northern Hemisphere spring, summer and fall. In the Southern Hemisphere, the TES methanol observations indicate a model overestimate over the bulk of South America from December through July, and a model underestimate during the biomass burning season.

Tropospheric methanol observations from space: retrieval evaluation and constraints on the seasonality of biogenic emissions.

Methanol retrievals from nadir-viewing space-based sensors offer powerful new information for quantifying methanol emissions on a global scale. Here we apply an ensemble of aircraft observations over North America to evaluate new methanol measurements from the Tropospheric Emission Spectrometer (TES) on the Aura satellite, and combine the TES data with observations from the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp-A satellite to investigate the seasonality of methanol emissions from northern midlatitude ecosystems. Using the GEOS-Chem chemical transport model as an intercomparison platform, we find that the TES retrieval performs well when the degrees of freedom for signal (DOFS) are above 0.5, in which case the model:TES regressions are generally consistent with the model:aircraft comparisons. Including retrievals with DOFS below 0.5 degrades the comparisons, as these are excessively influenced by the a priori. The comparisons suggest DOFS >0.5 as a minimum threshold for interpreting retrievals of trace gases with a weak tropospheric signal. We analyze one full year of satellite observations and find that GEOS-Chem, driven with MEGANv2.1 biogenic emissions, underestimates observed methanol concentrations throughout the midlatitudes in springtime, with the timing of the seasonal peak in model emissions 1-2 months too late. We attribute this discrepancy to an underestimate of emissions from new leaves in MEGAN, and apply the satellite data to better quantify the seasonal change in methanol emissions for midlatitude ecosystems. The derived parameters (relative emission factors of 11.0, 0.26, 0.12 and 3.0 for new, growing, mature, and old leaves, respectively, plus a leaf area index activity factor of 0.5 for expanding canopies with leaf area index <1.2) provide a more realistic simulation of seasonal methanol concentrations in midlatitudes on the basis of both the IASI and TES measurements.

Comprehensive versus matched psychosocial treatment in the MTA study: conceptual and empirical issues.

Addressed some factual inaccuracies and presented alternative positions on key issues raised in the article by Greene and Ablon (this issue) on the question, "What does the Multimodal Treatment Study (MTA) tell us about effective psychosocial treatment for attention deficit hyperactivity disorder (ADHD)?" The Greene and Ablon critique does not present for the reader's consideration the full range of findings from the MTA study, notably those most relevant to psychosocial treatment, and articulates a theoretical position that effective treatment requires matching treatment to children's assessed needs, an approach not taken in the MTA study. In this article, I present the full range of findings from the MTA study related to psychosocial treatment effects, correct the misperceptions that exist about the study based on limited reviews such as Greene and Ablon's, and review the empirical and experimental design issues that produced the decision by the MTA investigative team to study the effects of intensive, comprehensive psychosocial treatment. I argue that the questions asked by the MTA study about psychosocial treatment were important, relevant, and were addressed well in the MTA study design.

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.

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.

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.

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.

Surgical treatment of craniosynostosis: outcome analysis of 250 consecutive patients.

OBJECTIVE: Surgery for craniosynostosis has evolved rapidly over the past two decades, with increased emphasis on early, extensive operations. Older published series may not accurately reflect more recent experience. Our study was designed to analyze outcome in a large series of consecutive patients treated recently at a single center. METHODS: We reviewed 250 consecutive patients who underwent surgical treatment of craniosynostosis between January 1, 1987 and December 31, 1992. They were divided into nine groups by suture involvement: sagittal, unilateral coronal, bilateral coronal, unilateral lambdoid, bilateral lambdoid, metopic, multiple suture, the Klee-blattschädel deformity (cloverleaf skull), and acquired craniosynostosis. Outcome was analyzed in terms of residual deformities and irregularities, complications, mortality, as well as the need for additional surgery. RESULTS: There were 157 males (62. 8%) and 93 females (37.2%), with most of the male preponderance accounted for by the large sagittal synostosis group, which consisted of 82 males and 25 females. Median age at first operation was 147 days. A named syndrome was present in 23 patients (9.2%) and was more common than expected with bilateral and unilateral coronal synostosis, the Kleeblattschädel deformity, and multiple suture synostosis. There were two deaths (0.8%), both with Klee-blattschädel patients, and 17 other complications (6.8%). Morbidity and mortality were significantly associated with secondary vs primary operations and syndromic vs nonsyndromic patients. Outcome analysis revealed the best surgical results with metopic synostosis and significantly less good results with the Kleeblattschädel deformity, multiple suture synostosis, and bilateral coronal synostosis. CONCLUSIONS: Using modern surgical techniques, craniosynostosis can be corrected with good outcomes and relatively low morbidity and mortality, particularly for otherwise healthy, nonsyndromic infants.

The moderating effects of children's fear and activity level on relations between parenting practices and childhood symptomatology.

Parenting practices have been previously linked to childhood symptomatology. However, little consideration has been given to the potential effect of individual differences within the child on this relation. The current study assessed the moderating effects of children's activity level and fear on relations between parenting practices and childhood aggression and depressive symptoms using a sample of 64 fourth-, and fifth-grade boys. The findings showed that poorly monitored active boys and fearful boys who were exposed to harsh discipline exhibited high levels of aggression. Boys characterized by high fear who were exposed to harsh discipline or whose parents were extremely overinvolved showed elevated levels of depressive symptoms. These findings suggest that integrating children's individual differences with parenting models enhances our understanding of the etiology of childhood symptomatology. The intervention implications of such an integration are discussed.

A new self-report scale for assessment of adolescent psychopathology: factor structure, reliability, validity, and diagnostic sensitivity.

This paper describes four studies on self-reported problems in 2,243 adolescent males and females, 12 to 17 years of age. In Study 1, principal-axis factoring of 102 items covering 11 problem domains revealed six factors comprising 49.5% of the variance. Study 2 used confirmatory factor analysis of a 64-item reduced set on a new sample of 408 adolescents. Goodness-of-fit indicators suggested that the six-factor model had excellent fit to the data. Study 3 used data from the 2,157 adolescents used in the first two studies. Coefficient alphas ranged from .83 to .92. Median test-retest reliability for the six factors was .86. There was a consistent structure of the correlation matrix across age and gender. Study 4 was a study of criterion validity, using an additional sample of 86 children with attention-deficit hyperactivity disorder (ADHD). Sensitivity and specificity were high, with an overall diagnostic efficiency of 83%. This new self-report scale, the Conners/Wells Adolescent Self-Report of Symptoms (CASS), may provide a useful component of a multimodal assessment of adolescent psychopathology.