A Cognitive Social Skills Training Program

The generalized effects of a social skills training package based on self-instruction and on the social deficits of isolated children were evaluated in a multiple baseline design across subjects. Three preschool children were recommended by teachers as having extreme social withdrawal and were observed during free play in their classrooms. Daily ten-minute classroom free-play observations of four social behaviors in the experimenter's absence were conducted through all phases of the study. Two hour-long social skills training sessions were conducted with each child, practicing a series of graduated social encounters. Expectancy control sessions were conducted with the children not receiving training at that time. Follow-up observations were conducted with two of the children. The results indicated little generalized effect on any of the social behaviors for any subject. These data call into question the clinical utility of cognitive social skills training procedures as they are currently practiced.

Treatment of Severe Perceptual-Motor Disorders in Children Diagnosed as Learning Disabled

This study evaluates a procedure using positive reinforcement in the remediation of severe perceptual-motor disorders in the handwriting of four earning disabled boys. In Experiment 1, two of the students were asked to copy five words, five geometric figures, and their first name five times during each session. Following baseline in a multiple baseline design across subjects, token reinforcement was made contingent on correct responses (that contained no errors of orientation, sequence, or legibility), and corrective feedback was given following incorrect responses. Probe sessions during which the children copied different words and figures were interspersed three times during baseline and three times during treatment to assess the degree of generalization to new stimuli. Reinforcement and corrective feedback were not given during these sessions. When reinforcement and corrective feedback were introduced, substantial increases in the frequency of correct printings were found during both the treatment and probe sessions for both children. In Experiment 2, similar results were found for two learning disabled boys using a reversal design in one case and a multiple baseline across responses design in the other. A substantial degree of generalization to handwriting in the classroom was found for one student, but weaker evidence for generalization was found for the other.

Differential Diagnosis of Children with ADHD and ADHD/with Co-Occurring Conduct Disorder

The WISC-R factors, Verbal Comprehension, Perceptual Organization and Freedom from Distractibility (FFD) were examined for their discriminant validity in diagnosing children with Attention Deficit Hyperactivity Disorder (ADHD), ADHD with co-occurring Conduct Disorder (ADHD + CD) and those comprising a clinic control population. Contrary to expectations and clinical practice, the FFD factor did not significantly discriminate among children comprising the three diagnostic groups. The verbal comprehension and perceptual organizational factors significantly distinguished between children with and without conduct disorder, but not between the clinic control and ADHD children. Therefore, the ADHD + CD group's performance on the WISC-R factors qualitatively differs from children with internalizing disorders or ADHD, and as such is most likely a separate population. Furthermore, the use of the FFD factor did not provide sufficient sensitivity for a discriminative diagnosis (a miss rate of 50 percent for clinic control, 64.3 percent for ADHD and 38.1 percent for ADHD + CD).

Prenatal Cannabis and Tobacco Exposure in Relation to Brain Morphology: A Prospective Neuroimaging Study in Young Children

BACKGROUND

Cannabis use during pregnancy has been associated with negative behavioral outcomes and psychopathology in offspring. However, there has been little research evaluating alterations in brain structure as a result of maternal cannabis use. In this prospective study, we investigated the association between prenatal cannabis exposure and brain morphology in young children.

METHODS

We matched 96 children prenatally exposed to tobacco only (without cannabis) with 113 unexposed control subjects on the basis of age and gender and subsequently selected 54 children exposed to prenatal cannabis (mostly combined with tobacco exposure). These children (aged 6 to 8 years) were part of a population-based study in the Netherlands, the Generation R Study, and were followed from pregnancy onward. We assessed brain volumetric measures and cortical thickness in magnetic resonance imaging scans using FreeSurfer. We performed vertexwise analyses in FreeSurfer and linear regression analyses adjusting for relevant covariates using Statistical Package for the Social Sciences.

RESULTS

Prenatal cannabis exposure was not associated with global brain volumes, such as total brain volume, gray matter volume, or white matter volume. However, prenatal cannabis exposure was associated with differences in cortical thickness: compared with nonexposed control subjects, cannabis-exposed children had thicker frontal cortices. Prenatal tobacco exposure compared with nonexposed control subjects was associated with cortical thinning, primarily in the superior frontal and superior parietal cortices.

CONCLUSIONS

Our findings suggest an association between prenatal cannabis exposure and cortical thickness in children. Further research is needed to explore the causal nature of this association.

Callous traits in children with and without conduct problems predict reduced connectivity when viewing harm to others

The presence of elevated callous unemotional (CU) traits seems to designate a distinct group of children and adolescents with serious conduct problems. However, the extent to which CU traits impact the aversive reaction to harm is still a contentious issue. Here, we examined the effective connectivity seeded in the anterior insula and anterior cingulate cortex in a large number of children (N = 123, age 9-11, 60 females) with various levels of conduct disorder (CD) symptoms in response to visual stimuli depicting other people being physically injured. Perceiving others being harmed was associated with increased hemodynamic activity in the left amygdala and right temporoparietal junction (rTPJ). Children with higher callous traits showed less functional connectivity seeded in anterior cingulate with left amygdala and anterior insula. Conversely, CD symptoms were positively related to connectivity of insula with rTPJ. Overall, these results suggest that callousness is marked by the disruption of widespread cortical networks responsible for detecting and appropriately responding to important environmental cues, such as the distress of others.

Sex differences in abnormal white matter development associated with conduct disorder in children

Associations between white matter pathway abnormalities and antisocial personality disorder in adults are well replicated, and there is some evidence for an association of white matter abnormalities with conduct disorder (CD) in adolescents. In this study, white matter maturation using diffusion tensor imaging (DTI) was examined in 110 children aged 10.0 ± 0.8 years selected to vary widely in their numbers of CD symptoms. The results replicated age-related increases in fractional anisotropy (FA) found in previous studies. There was not a significant association between the number of CD symptoms and FA, but CD symptoms were found to be significantly associated with greater axial and radial diffusivity in a broad range of white matter tracts, particularly in girls. In complementary analyses, there were similar significant differences in axial and radial diffusivity between children who met diagnostic criteria for CD and healthy children with no symptoms of CD, particularly in girls. Brain structural abnormalities may contribute to the emergence of CD in childhood, perhaps playing a greater role in girls.

Prospective association of childhood receptive vocabulary and conduct problems with self-reported adolescent delinquency: tests of mediation and moderation in sibling-comparison analyses

Associations among receptive vocabulary measured at 4-9 years, mother-reported childhood conduct problems at 4-9 years, and self-reported adolescent delinquency at 14-17 years were assessed using data from a prospective study of the offspring of a large U.S. nationally representative sample of women. A novel quasi-experimental strategy was used to rule out family-level confounding by estimating path-analytic associations within families in a sibling comparison design. This allowed simultaneous tests of the direct and indirect effects of receptive vocabulary and childhood conduct problems, and of their joint moderation, on adolescent delinquency without family-level environmental confounding. The significant association of receptive vocabulary with later adolescent delinquency was indirect, mediated by childhood conduct problems. Furthermore, a significant interaction between receptive vocabulary and childhood conduct problems reflected a steeper slope for the predictive association between childhood conduct problems and adolescent delinquency when receptive vocabulary scores were higher. These findings of significant indirect association were qualitatively identical in both population-level and within-family analyses, suggesting that they are not the result of family-level confounds.

Genetics in child and adolescent psychiatry: methodological advances and conceptual issues

Discovering the genetic basis of early-onset psychiatric disorders has been the aim of intensive research during the last decade. We will first selectively summarize results of genetic research in child and adolescent psychiatry by using examples from different disorders and discuss methodological issues, emerging questions and future directions. In the second part of this review, we will focus on how to link genetic causes of disorders with physiological pathways, discuss the impact of genetic findings on diagnostic systems, prevention and therapeutic interventions. Finally we will highlight some ethical aspects connected to genetic research in child and adolescent psychiatry. Advances in molecular genetic methods have led to insights into the genetic architecture of psychiatric disorders, but not yet provided definite pathways to pathophysiology. If replicated, promising findings from genetic studies might in some cases lead to personalized treatments. On the one hand, knowledge of the genetic basis of disorders may influence diagnostic categories. On the other hand, models also suggest studying the genetic architecture of psychiatric disorders across diagnoses and clinical groups.

Marked reduction in serotonergic activity in a sexually aggressive adolescent male

Serotonergic dysfunctions are implicated in conduct disorder, impulsivity, and aggression. Early adverse experiences increase the risk for these behaviors in adolescents. The authors investigated serotonergic activity in one adolescent male who experienced maternal abandonment and childhood abuse and exhibited severely aggressive sexual offenses. Platelet serotonin (5-HT) concentration, [14C]-5HT uptake kinetics, and plasma prolactin, cortisol response to D,L-fenfluramine (D,L-FEN) were measured. Results showed extremely low 5-HT concentration (2.9+/-0.7 ng/10⁸ platelets), [14C]-5HT uptake rate (0.5+/-0.04 mM/min/10⁷ platelets), undetectable Km and Vmax, and abnormally blunted prolactin, cortisol response to D,L-FEN. These abnormalities in this sexually aggressive adolescent may be a consequence of childhood abuse.

What we need to know about callous-unemotional traits: comment on Frick, Ray, Thornton, and Kahn (2014)

Frick, Ray, Thornton, and Kahn (2014) presented a comprehensive and well-articulated review of studies relevant to the validity and utility of using callous-unemotional traits to subtype the diagnosis of conduct disorder (CD). Like definitions of subtypes of CD in previous versions of the Diagnostic and Statistical Manual of Mental Disorders, the available evidence on the validity of the new subtypes of CD in the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5; American Psychiatric Association, 2013) based on callous-unemotional traits is thin. Nonetheless, the target article makes a compelling argument for further study of callous-unemotional and related traits to better understand the heterogeneity of CD. In particular, the possibilities that callous-unemotional traits may facilitate understanding of etiology and psychobiological mechanisms and may help predict the prognosis and treatment outcomes of children with CD deserve greater study. Future research must be stronger than previous research, however, in using more appropriate samples of children with CD along with more informative designs, and in conducting analyses to directly test the incremental validity of callous-unemotional traits as a subtyping variable beyond the severity or aggressiveness of CD.

Criterion validity of the general factor of psychopathology in a prospective study of girls

BACKGROUND

The best-fitting model of the structure of common psychopathology often includes a general factor on which all dimensions of psychopathology load. Such a general factor would be important if it reflects etiologies and mechanisms shared by all dimensions of psychopathology. Nonetheless, a viable alternative explanation is that the general factor is partly or wholly a result of common method variance or other systematic measurement biases.

METHODS

To test this alternative explanation, we extracted general, externalizing, and internalizing factor scores using mother-reported symptoms across 5-11 years of age in confirmatory factor analyses of data from a representative longitudinal study of 2,450 girls. Independent associations between the three psychopathology factor scores and teacher-reported criterion variables were estimated in multiple regression, controlling intelligence, and demographic covariates.

RESULTS

The model including the general factor fit significantly better than a correlated two-factor (internalizing/externalizing) model. The general factor was robustly and independently associated with all measures of teacher-reported school functioning concurrently during childhood and prospectively during adolescence.

CONCLUSIONS

These findings weaken the hypothesis that the general factor of psychopathology in childhood is solely a measurement artifact and support further research on the substantive meaning of the general factor.

Comorbidity Among Dimensions of Childhood Psychopathology: Converging Evidence from Behavior Genetics

In this article, we review evidence from recent behavior genetic studies that examined the covariance among common childhood psychopathological conditions and tested specific hypotheses regarding common and broadband-specific underlying features of childhood psychopathology. Specifically, we review the distinction between internalizing and externalizing disorders, the support for the generalist genes and specialist environments model, negative emotionality as a heritable underlying feature common to both internalizing and externalizing disorders, and daring as a heritable broadband-specific underlying feature that distinguishes externalizing disorders from internalizing disorders. We also discuss the implications of research in the search for specific genes that influence childhood psychopathology and suggest avenues for new research.

Association of regional gray matter volumes in the brain with disruptive behavior disorders in male and female children

Because the disruptive behavior disorders are highly impairing conditions, it is important to determine if structural variations in brain are associated early in life with these problems among children. Structural MRI data were acquired from 111 9-11 year olds (58 girls and 53 boys), 43 who met diagnostic criteria for oppositional defiant disorder and/or conduct disorder and 68 healthy controls. Voxel-based morphometry was used to examine associations of behavioral measures with gray matter volumes in whole-brain analyses. Unlike previous studies, variation in gray matter volume was not found to be associated with a disruptive behavior disorder diagnosis in any brain region at p < .05 with FWE correction. Nonetheless, an inverse nonlinear association of the number of conduct disorder (CD) symptoms with gray matter volume along the left superior temporal sulcus was significant in the full sample (p < .05 with FWE correction), with a trend in the right hemisphere (p < 0.001 uncorrected). There also was a trend toward a stronger association of the number of CD symptoms with gray matter volume along the left superior temporal sulcus in girls than boys. The present findings did not replicate previous findings of reduced gray matter volumes in the anterior insula, amygdala, and frontal cortex in youth with CD, but are consistent with previous findings of reduced gray matter volumes in temporal regions, particularly in girls.

Patterns of heterotypic continuity associated with the cross-sectional correlational structure of prevalent mental disorders in adults

IMPORTANCE

Mental disorders predict future occurrences of both the same disorder (homotypic continuity) and other disorders (heterotypic continuity). Heterotypic continuity is inconsistent with a view of mental disorders as fixed entities. In contrast, hierarchical-dimensional conceptualizations of psychopathology, in which each form of psychopathology is hypothesized to have both unique and broadly shared etiologies and mechanisms, predict both homotypic and heterotypic continuity.

OBJECTIVE

To test predictions derived from a hierarchical-dimensional model of psychopathology that (1) heterotypic continuity is widespread, even controlling for homotypic continuity, and that (2) the relative magnitudes of heterotypic continuities recapitulate the relative magnitudes of cross-sectional correlations among diagnoses at baseline.

DESIGN, SETTING, AND PARTICIPANTS

Ten prevalent diagnoses were assessed in the same person twice (ie, in 2 waves separated by 3 years). We used a representative sample of adults in the United States (i.e., 28,958 participants 18-64 years of age in the National Epidemiologic Study of Alcohol and Related Conditions who were assessed in both waves).

MAIN OUTCOMES AND MEASURES

Diagnoses from reliable and valid structured interviews.

RESULTS

Adjusting for sex and age, we found that bivariate associations of all pairs of diagnoses from wave 1 to wave 2 exceeded chance levels (P < .05) for all homotypic (median tetrachoric correlation of ρ = 0.54 [range, 0.41-0.79]) and for nearly all heterotypic continuities (median tetrachoric correlation of ρ = 0.28 [range, 0.07-0.50]). Significant heterotypic continuity was widespread even when all wave 1 diagnoses (including the same diagnosis) were simultaneous predictors of each wave 2 diagnosis. The rank correlation between age- and sex-adjusted tetrachoric correlation for cross-sectional associations among wave 1 diagnoses and for heterotypic associations from wave 1 to wave 2 diagnoses was ρ = 0.86 (P < .001).

CONCLUSIONS AND RELEVANCE

For these prevalent mental disorders, heterotypic continuity was nearly universal and not an artifact of failure to control for homotypic continuity. Furthermore, the relative magnitudes of heterotypic continuity closely mirrored the relative magnitudes of cross-sectional associations among these disorders, consistent with the hypothesis that both sets of associations reflect the same factors. Mental disorders are not fixed and independent entities. Rather, each diagnosis is robustly related to other diagnoses in a correlational structure that is manifested both concurrently and in patterns of heterotypic continuity across time.

Common genetic influences on negative emotionality and a general psychopathology factor in childhood and adolescence

Previous research using confirmatory factor analysis to model psychopathology comorbidity has supported the hypothesis of a broad general factor (i.e., a "bifactor"; Holzinger & Swineford, 1937) of psychopathology in children, adolescents, and adults, with more specific higher order internalizing and externalizing factors reflecting additional shared variance in symptoms (Lahey et al., 2012; Lahey, van Hulle, Singh, Waldman, & Rathouz, 2011). The psychological nature of this general factor has not been explored, however. The current study tested a prediction, derived from the spectrum hypothesis of personality and psychopathology, that variance in a general psychopathology bifactor overlaps substantially-at both phenotypic and genetic levels-with the dispositional trait of negative emotionality. Data on psychopathology symptoms and dispositional traits were collected from both parents and youth in a representative sample of 1,569 twin pairs (ages 9-17 years) from Tennessee. Predictions based on the spectrum hypothesis were supported, with variance in negative emotionality and the general factor overlapping substantially at both phenotypic and etiologic levels. Furthermore, stronger correlations were found between negative emotionality and the general psychopathology factor than among other dispositions and other psychopathology factors.

Testing the Developmental Origins of Health and Disease Hypothesis for Psychopathology Using Family-Based Quasi-Experimental Designs

The Developmental Origin of Health and Disease (DOHaD) hypothesis is a broad theoretical framework that emphasizes how early risk factors have a causal influence on psychopathology. Researchers have raised concerns about the causal interpretation of statistical associations between early risk factors and later psychopathology because most existing studies have been unable to rule out the possibility of environmental and genetic confounding. In this paper we illustrate how family-based quasi-experimental designs can test the DOHaD hypothesis by ruling out alternative hypotheses. We review the logic underlying sibling-comparison, co-twin control, offspring of siblings/twins, adoption, and in vitro fertilization designs. We then present results from studies using these designs focused on broad indices of fetal development (low birth weight and gestational age) and a particular teratogen, smoking during pregnancy. The results provide mixed support for the DOHaD hypothesis for psychopathology, illustrating the critical need to use design features that rule out unmeasured confounding.

The role of early childhood ADHD and subsequent CD in the initiation and escalation of adolescent cigarette, alcohol, and marijuana use

Adolescents with attention deficit/hyperactivity disorder (ADHD) are at an increased risk for substance use but the pathways through which this risk emerges are insufficiently understood. Tobacco, alcohol, and marijuana outcomes were compared between adolescents diagnosed with ADHD in early childhood (N = 113) and demographically similar controls (N = 65). Participants were assessed from age 5 until age 18. A comprehensive history of adolescent substance use was compiled for each participant and growth in ADHD and conduct disorder (CD) were modeled as they related to substance use outcomes. Results indicated that when compared with controls, adolescents with ADHD were more likely to try cigarettes, initiate alcohol use at early ages, and smoke marijuana more frequently. Furthermore, adolescents with ADHD were 4 to 5 times more likely than controls to escalate to heavy cigarette and marijuana use after trying these substances once. Adolescents with ADHD who escalated to heavy use patterns were more likely to display early cigarette use and marked problems with family members, but displayed fewer peer problems. There was evidence of baseline effects (latent intercept, measured at age 5) for both ADHD and CD on substance use outcomes. Furthermore, growth in ADHD symptoms accounted for much of the growth in CD symptoms, and consequently, escalating CD symptoms in childhood (latent slope) were viewed as a mediator of the relationship between ADHD and cigarette and marijuana use. Maternal drinking in early childhood was the strongest predictor of early adolescent alcohol use. These findings are discussed with respect to the role of ADHD in the development of adolescent risk outcomes.

Genetic imaging of the association of oxytocin receptor gene (OXTR) polymorphisms with positive maternal parenting

Background: Well-validated models of maternal behavior in small-brain mammals posit a central role of oxytocin in parenting, by reducing stress and enhancing the reward value of social interactions with offspring. In contrast, human studies are only beginning to gain insights into how oxytocin modulates maternal behavior and affiliation.

Methods: To explore associations between oxytocin receptor genes and maternal parenting behavior in humans, we conducted a genetic imaging study of women selected to exhibit a wide range of observed parenting when their children were 4–6 years old.

Results: In response to child stimuli during functional magnetic resonance imaging (fMRI), hemodynamic responses in brain regions that mediate affect, reward, and social behavior were significantly correlated with observed positive parenting. Furthermore, single nucleotide polymorphisms (SNPs) (rs53576 and rs1042778) in the gene encoding the oxytocin receptor were significantly associated with both positive parenting and hemodynamic responses to child stimuli in orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), and hippocampus.

Conclusions: These findings contribute to the emerging literature on the role of oxytocin in human social behavior and support the feasibility of tracing biological pathways from genes to neural regions to positive maternal parenting behaviors in humans using genetic imaging methods.

Personality dimensions as common and broadband-specific features for internalizing and externalizing disorders

Several researchers have suggested that the nature of the covariation between internalizing and externalizing disorders may be understood better by examining the associations between temperament or personality and these disorders. The present study examined neuroticism as a potential common feature underlying both internalizing and externalizing disorders and novelty seeking as a potential broad-band specific feature influencing externalizing disorders alone. Participants were 12- to 18-year-old twin pairs (635 monozygotic twin pairs and 691 dizygotic twin pairs; 48 % male and 52 % female) recruited from the Colorado Center for Antisocial Drug Dependence. Genetic and nonshared environmental influences shared in common with neuroticism influenced the covariation among distinct internalizing disorders, the covariation among distinct externalizing disorders, and the covariation between internalizing and externalizing disorders. Genetic influences shared in common with novelty seeking influenced the covariation among externalizing disorders and the covariation between major depressive disorder and externalizing disorders, but not the covariation among internalizing disorders or between anxiety disorders and externalizing disorders. Also, after accounting for genetic and environmental influences shared in common with neuroticism and novelty seeking, there were no significant common genetic or environmental influences among the disorders examined, suggesting that the covariance among the disorders is sufficiently explained by neuroticism and novelty seeking. We conclude that neuroticism is a heritable common feature of both internalizing disorders and externalizing disorders, and that novelty seeking is a heritable broad-band specific factor that distinguishes anxiety disorders from externalizing disorders.

Critical need for family-based, quasi-experimental designs in integrating genetic and social science research

Researchers have identified environmental risks that predict subsequent psychological and medical problems. Based on these correlational findings, researchers have developed and tested complex developmental models and have examined biological moderating factors (e.g., gene-environment interactions). In this context, we stress the critical need for researchers to use family-based, quasi-experimental designs when trying to integrate genetic and social science research involving environmental variables because these designs rigorously examine causal inferences by testing competing hypotheses. We argue that sibling comparison, offspring of twins or siblings, in vitro fertilization designs, and other genetically informed approaches play a unique role in bridging gaps between basic biological and social science research. We use studies on maternal smoking during pregnancy to exemplify these principles.

Does low birth weight share common genetic or environmental risk with childhood disruptive disorders?

Although advances in neonatal care over the past century have resulted in increased rates of survival among at-risk births, including infants with low birth weight, we have much to learn about psychological outcomes in this population. In particular, despite growing evidence that low birth weight may be associated with an increased risk for Attention-Deficit/Hyperactive Disorder (ADHD) symptoms in childhood, few studies have examined birth weight as a risk factor for disruptive disorders that commonly co-occur with ADHD. In addition, the etiology of the relation between birth weight and these disorders is unknown. The current investigation aimed to better understand these associations in the context of potentially confounding genetic and environmental influences by examining phenotypic associations between birth weight and disruptive disorder symptoms both between families and within families in two independent twin samples (Sample 1: N = 1,676 individuals; Sample 2: N = 4,038 individuals). We found negative associations between birth weight and inattentive, hyperactive-impulsive, and broad externalizing symptoms in both samples. Nonetheless, the overall magnitude of these associations was very small, contributing to less than 1% of the variance in these symptom dimensions. Within-family associations between birth weight and disruptive disorder symptoms did not differ for monozygotic and dizygotic twin pairs, suggesting that nonshared environmental influences rather than common genetic influences are responsible for these associations. Overall, the consistent albeit weak associations between birth weight and disruptive disorder symptoms suggest that low birth weight may not represent a major risk factor in the development of these symptoms.

Effects of multiple maternal relationship transitions on offspring antisocial behavior in childhood and adolescence: a cousin-comparison analysis

Previous studies of the association between multiple parental relationship transitions (i.e., when a parent begins or terminates an intimate relationship involving cohabitation) and offspring antisocial behavior have varied in their efforts to rule out confounding influences, such as parental antisocial behavior and low income. They also have been limited in the representativeness of their samples. Thus, it remains unclear to what degree parents' multiple relationship transitions have independent effects on children's antisocial behavior. Analyses were conducted using data on 8,652 6-9-year-old, 6,911 10-13-year-old, and 6,495 14-17-year-old offspring of a nationally representative sample of U.S. women. Cousin-comparisons were used in combination with statistical covariates to evaluate the associations between maternal relationship transitions and offspring antisocial behavior in childhood and adolescence. Cousin-comparisons suggested that associations between maternal relationship transitions and antisocial behavior in childhood and early adolescence are largely explained by confounding factors. In contrast, the associations between maternal relationship transitions and offspring delinquency in late adolescence were robust to measured and unmeasured confounds. The present findings suggest that interventions aimed at reducing exposure to parental relationship transitions or addressing the psychosocial consequences of exposure to parental relationship transitions could reduce risk for offspring delinquency in late adolescence.

Early concern and disregard for others as predictors of antisocial behavior

BACKGROUND

Prediction of antisocial behavior is important, given its adverse impact on both the individuals engaging in antisocial behavior and society. Additional research identifying early predictors of future antisocial behavior, or antisocial propensity, is needed. The present study tested the hypothesis that both concern for others and active disregard for others in distress in toddlers and young children predict antisocial behavior during middle childhood and adolescence.

METHODS

A representative sample of same-sex twins (N=956) recruited in Colorado was examined. Mother-rated and researcher-observed concern and disregard for others assessed at age 14-36 months were examined as predictors of parent- (age 4-12), teacher- (age 7-12), and self-reported (age 17) antisocial behavior.

RESULTS

  Observed disregard for others predicted antisocial behavior assessed by three different informants (parents, teachers, and self), including antisocial behavior assessed 14 years later. It also predicted a higher order antisocial behavior factor (β=.58, p<.01) after controlling for observed concern for others. Mother-rated disregard for others predicted parent-reported antisocial behavior. Contrary to predictions, neither mother-rated nor observed concern for others inversely predicted antisocial behavior. RESULTS of twin analyses suggested that the covariation between observed disregard for others and antisocial behavior was due to shared environmental influences.

CONCLUSIONS

Disregard for others in toddlerhood/early childhood is a strong predictor of antisocial behavior in middle childhood and adolescence. The results suggest the potential need for early assessment of disregard for others and the development of potential interventions.

Familial confounding of the association between maternal smoking during pregnancy and offspring substance use and problems

CONTEXT

Previous epidemiological, animal, and human cognitive neuroscience research suggests that maternal smoking during pregnancy (SDP) causes increased risk of substance use/problems in offspring.

OBJECTIVE

To determine the extent to which the association between SDP and offspring substance use/problems depends on confounded familial background factors by using a quasi-experimental design.

DESIGN

We used 2 separate samples from the United States and Sweden. The analyses prospectively predicted multiple indices of substance use and problems while controlling for statistical covariates and comparing differentially exposed siblings to minimize confounding.

SETTING

Offspring of a representative sample of women in the United States (sample 1) and the total Swedish population born during the period from January 1, 1983, to December 31, 1995 (sample 2).

PATIENTS OR OTHER PARTICIPANTS

Adolescent offspring of the women in the National Longitudinal Survey of Youth 1979 (n = 6904) and all offspring born in Sweden during the 13-year period (n = 1,187,360).

MAIN OUTCOME MEASURES

Self-reported adolescent alcohol, cigarette, and marijuana use and early onset (before 14 years of age) of each substance (sample 1) and substance-related convictions and hospitalizations for an alcohol- or other drug-related problem (sample 2).

RESULTS

The same pattern emerged for each index of substance use/problems across the 2 samples. At the population level, maternal SDP predicted every measure of offspring substance use/problems in both samples, ranging from adolescent alcohol use (hazard ratio [HR](moderate), 1.32 [95% CI, 1.22-1.43]; HR(high), 1.33 [1.17-1.53]) to a narcotics-related conviction (HR(moderate), 2.23 [2.14-2.31]; HR(high), 2.97 [2.86-3.09]). When comparing differentially exposed siblings to minimize genetic and environmental confounds, however, the association between SDP and each measure of substance use/problems was minimal and not statistically significant.

CONCLUSIONS

The association between maternal SDP and offspring substance use/problems is likely due to familial background factors, not a causal influence, because siblings have similar rates of substance use and problems regardless of their specific exposure to SDP.

Operating characteristics of alternative statistical methods for detecting gene-by-measured environment interaction in the presence of gene-environment correlation in twin and sibling studies

It is likely that all complex behaviors and diseases result from interactions between genetic vulnerabilities and environmental factors. Accurately identifying such gene-environment interactions is of critical importance for genetic research on health and behavior. In a previous article we proposed a set of models for testing alternative relationships between a phenotype (P) and a putative moderator (M) in twin studies. These include the traditional bivariate Cholesky model, an extension of that model that allows for interactions between M and the underling influences on P, and a model in which M has a non-linear main effect on P. Here we use simulations to evaluate the type I error rates, power, and performance of the Bayesian Information Criterion under a variety of data generating mechanisms and samples sizes (n = 2,000 and n = 500 twin pairs). In testing the extension of the Cholesky model, false positive rates consistently fell short of the nominal Type I error rates ([Formula: see text]). With adequate sample size (n = 2,000 pairs), the correct model had the lowest BIC value in nearly all simulated datasets. With lower sample sizes, models specifying non-linear main effects were more difficult to distinguish from models containing interaction effects. In addition, we provide an illustration of our approach by examining possible interactions between birthweight and the genetic and environmental influences on child and adolescent anxiety using previously collected data. We found a significant interaction between birthweight and the genetic and environmental influences on anxiety. However, the interaction was accounted for by non-linear main effects of birthweight on anxiety, verifying that interaction effects need to be tested against alternative models.

Is there a general factor of prevalent psychopathology during adulthood?

The patterns of comorbidity among prevalent mental disorders in adults lead them to load on "externalizing," "distress," and "fears" factors. These factors are themselves robustly correlated, but little attention has been paid to this fact. As a first step in studying the implications of these interfactor correlations, we conducted confirmatory factor analyses on diagnoses of 11 prevalent Diagnostic and Statistical Manual of Mental Disorders (4th ed.) mental disorders in a nationally representative sample. A model specifying correlated externalizing, distress, and fears factors fit well, but an alternative model was tested in which a "general" bifactor was added to capture what these disorders share in common. There was a modest but significant improvement in fit for the bifactor model relative to the 3-factor oblique model, with all disorders loading strongly on the bifactor. Tests of external validity revealed that the fears, distress, and externalizing factors were differentially associated with measures of functioning and potential risk factors. Nonetheless, the general bifactor accounted for significant independent variance in future psychopathology, functioning, and other criteria over and above the fears, distress, and externalizing factors. These findings support the hypothesis that these prevalent forms of psychopathology have both important common and unique features. Future studies should determine whether this is because they share elements of their etiology and neurobiological mechanisms. If so, the existence of common features across diverse forms of prevalent psychopathology could have important implications for understanding the nature, etiology, and outcomes of psychopathology.

Preliminary genetic imaging study of the association between estrogen receptor-α gene polymorphisms and harsh human maternal parenting

A failure of neural changes initiated by the estrogen surge in late pregnancy to reverse the valence of infant stimuli from aversive to rewarding is associated with dysfunctional maternal behavior in nonhuman mammals. Estrogen receptor-α plays the crucial role in mediating these neural effects of estrogen priming. This preliminary study examines associations between estrogen receptor-α gene polymorphisms and human maternal behavior. Two polymorphisms were associated with human negative maternal parenting. Furthermore, hemodynamic responses in functional magnetic resonance imaging to child stimuli in neural regions associated with social cognition fully mediated the association between genetic variation and negative parenting. This suggests testable hypotheses regarding a biological pathway between genetic variants and dysfunctional human maternal parenting.

Is maternal smoking during pregnancy a causal environmental risk factor for adolescent antisocial behavior? Testing etiological theories and assumptions

BACKGROUND

Although many studies indicate that maternal smoking during pregnancy (SDP) is correlated with later offspring antisocial behavior (ASB), recent quasi-experimental studies suggest that background familial factors confound the association. The present study sought to test alternative etiological hypotheses using multiple indices of adolescent ASB, comparing differentially exposed siblings, and testing assumptions in the sibling-comparison design.

METHOD

The study examined the association between maternal SDP and adolescent-reported ASB, criminal convictions and membership in a group of individuals with early-starting and chronic ASB among 6066 offspring of women from the National Longitudinal Survey of Youth, a representative sample of women in the USA. The analyses controlled for statistical covariates and examined associations while comparing differentially exposed siblings.

RESULTS

At the population level, each additional pack of cigarettes per day predicted greater mean adolescent-reported ASB symptoms [ratio of means 1.15, 95% confidence interval (CI) 1.08-1.22], odds of being in the top 10% of ASB [odds ratio (OR) 1.34, 95% CI 1.10-1.65], hazard of a criminal conviction [hazard ratio (HR) 1.51, 95% CI 1.34-1.68] and odds of chronic ASB (OR 1.57, 95% CI 1.25-1.99). SDP robustly predicted most assessments of ASB while controlling for measured covariates. When siblings exposed to differing levels of SDP were compared, however, all of the associations were attenuated and were not statistically significant: adolescent-reported mean ASB (ratio of means 0.86, 95% CI 0.74-1.01), high ASB (OR 0.67, 95% CI 0.41-1.12), criminal conviction (HR 0.98, 95% CI 0.66-1.44) and chronic ASB (OR 0.80, 95% CI 0.46-1.38).

CONCLUSIONS

The results strongly suggest that familial factors account for the correlation between SDP and offspring adolescent ASB, rather than a putative causal environmental influence of SDP.

Impulsivity and the modular organization of resting-state neural networks

Impulsivity is a complex trait associated with a range of maladaptive behaviors, including many forms of psychopathology. Previous research has implicated multiple neural circuits and neurotransmitter systems in impulsive behavior, but the relationship between impulsivity and organization of whole-brain networks has not yet been explored. Using graph theory analyses, we characterized the relationship between impulsivity and the functional segregation ("modularity") of the whole-brain network architecture derived from resting-state functional magnetic resonance imaging (fMRI) data. These analyses revealed remarkable differences in network organization across the impulsivity spectrum. Specifically, in highly impulsive individuals, regulatory structures including medial and lateral regions of the prefrontal cortex were isolated from subcortical structures associated with appetitive drive, whereas these brain areas clustered together within the same module in less impulsive individuals. Further exploration of the modular organization of whole-brain networks revealed novel shifts in the functional connectivity between visual, sensorimotor, cortical, and subcortical structures across the impulsivity spectrum. The current findings highlight the utility of graph theory analyses of resting-state fMRI data in furthering our understanding of the neurobiological architecture of complex behaviors.

Validity of DSM-IV attention deficit/hyperactivity disorder symptom dimensions and subtypes

Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) criteria for attention deficit/hyperactivity disorder (ADHD) specify two dimensions of inattention and hyperactivity-impulsivity symptoms that are used to define three nominal subtypes: predominantly hyperactive-impulsive type (ADHD-H), predominantly inattentive type (ADHD-I), and combined type (ADHD-C). To aid decision making for DSM-5 and other future diagnostic systems, a comprehensive literature review and meta-analysis of 546 studies was completed to evaluate the validity of the DSM-IV model of ADHD. Results indicated that DSM-IV criteria identify individuals with significant and persistent impairment in social, academic, occupational, and adaptive functioning when intelligence, demographic factors, and concurrent psychopathology are controlled. Available data overwhelmingly support the concurrent, predictive, and discriminant validity of the distinction between inattention and hyperactivity-impulsivity symptoms, and indicate that nearly all differences among the nominal subtypes are consistent with the relative levels of inattention and hyperactivity-impulsivity symptoms that define the subtypes. In contrast, the DSM-IV subtype model is compromised by weak evidence for the validity of ADHD-H after first grade, minimal support for the distinction between ADHD-I and ADHD-C in studies of etiological influences, academic and cognitive functioning, and treatment response, and the marked longitudinal instability of all three subtypes. Overall, we conclude that the DSM-IV ADHD subtypes provide a convenient clinical shorthand to describe the functional and behavioral correlates of current levels of inattention and hyperactivity-impulsivity symptoms, but do not identify discrete subgroups with sufficient long-term stability to justify the classification of distinct forms of the disorder. Empirical support is stronger for an alternative model that would replace the subtypes with dimensional modifiers that reflect the number of inattention and hyperactivity-impulsivity symptoms at the time of assessment. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

Annual research review: phenotypic and causal structure of conduct disorder in the broader context of prevalent forms of psychopathology

BACKGROUND

A better understanding of the nature and etiology of conduct disorder (CD) can inform nosology and vice versa. We posit that any prevalent form of psychopathology, including CD, can be best understood if it is studied in the context of other correlated forms of child and adolescent psychopathology using formal models to guide inquiry.

METHODS

Review of both cross-sectional and longitudinal studies of the place of CD in the phenotypic and causal structure of prevalent psychopathology, with an emphasis on similarities and differences between CD and oppositional defiant disorder (ODD). Papers were located using Web of Science by topic searches with no restriction on year of publication.

RESULTS

Although some important nosologic questions remain unanswered, the dimensional phenotype of CD is well defined. CD differs from other disorders in its correlates, associated impairment, and course. Nonetheless, it is robustly correlated with many other prevalent dimensions of psychopathology both concurrently and predictively, including both other 'externalizing' disorders and some 'internalizing' disorders. Based on emerging evidence, we hypothesize that these concurrent and predictive correlations result primarily from widespread genetic pleiotropy, with some genetic factors nonspecifically influencing risk for multiple correlated dimensions of psychopathology. In contrast, environmental influences mostly act to differentiate dimensions of psychopathology from one another both concurrently and over time. CD and ODD share half of their genetic influences, but their genetic etiologies are distinct in other ways. Unlike most other dimensions of psychopathology, half of the genetic influences on CD appear to be unique to CD. In contrast, ODD broadly shares nearly all of its genetic influences with other disorders and has little unique genetic variance.

CONCLUSIONS

Conduct disorder is a relatively distinct syndrome at both phenotypic and etiologic levels, but much is revealed by studying CD in the context of its causal and phenotypic associations with other disorders over time. Advancing and refining formal causal models that specify the common and unique causes and biological mechanisms underlying each correlated dimension of psychopathology should facilitate research on the fundamental nature and nosology of CD.

Using confirmatory factor analysis to measure contemporaneous activation of defined neuronal networks in functional magnetic resonance imaging

Functional neuroimaging often generates large amounts of data on regions of interest. Such data can be addressed effectively with a widely-used statistical technique based on measurement theory that has not yet been applied to neuroimaging. Confirmatory factor analysis is a convenient hypothesis-driven modeling environment that can be used to conduct formal statistical tests comparing alternative hypotheses regarding the elements of putative neuronal networks. In such models, measures of each activated region of interest are treated as indicators of an underlying latent construct that represents the contemporaneous activation of the elements in the network. As such, confirmatory factor analysis focuses analyses on the activation of hypothesized networks as a whole, improves statistical power by modeling measurement error, and provides a theory-based approach to data reduction with a robust statistical basis. This approach is illustrated using data on seven regions of interest in a hypothesized mesocorticostriatal reward system in a sample of 262 adult volunteers assessed during a card-guessing reward task. A latent construct reflecting contemporaneous activation of the reward system was found to be significantly associated with a latent construct measuring impulsivity, particularly in males.

A quasi-experimental analysis of the influence of neighborhood disadvantage on child and adolescent conduct problems

A quasi-experimental comparison of cousins differentially exposed to levels of neighborhood disadvantage (ND) was used with extensive measured covariates to test the hypothesis that neighborhood risk has independent effects on youth conduct problems (CPs). Multilevel analyses were based on mother-rated ND and both mother-reported CPs across 4-13 years (n = 7,077) and youth-reported CPs across 10-13 years (n = 4,524) from the Children of the National Longitudinal Survey of Youth. ND was robustly related to CPs reported by both informants when controlling for both measured risk factors that are correlated with ND and unmeasured confounds. These findings are consistent with the hypothesis that ND has influence on conduct problems.

Shared genetic influences on negative emotionality and major depression/conduct disorder comorbidity

OBJECTIVE

To investigate whether genetic contributions to major depressive disorder and conduct disorder comorbidity are shared with genetic influences on negative emotionality.

METHOD

Primary caregivers of 2,022 same- and opposite-sex twin pairs 6 to 18 years of age comprised a population-based sample. Participants were randomly selected across five regions in Tennessee, with stratification by age and geographic location. Face-to-face structured interviews were conducted with the primary caregiver of a representative sample of twins.

RESULTS

After accounting for genetic influences on negative emotionality, genetic influences on major depressive disorder/conduct disorder comorbidity were nonsignficant, but only in male twins. Specifically, 19% of the variance in the two disorders was accounted for by genetic factors shared with negative emotionality in male twins. Although the full hypothesis could not be tested in female twins, 10% to 11% of the variance in the two disorders was also accounted for by genetic factors shared with negative emotionality. Common shared environmental and nonshared environmental influences were found for major depressive disorder/conduct disorder comorbidity in male and female twins.

CONCLUSIONS

Negative emotionality represents an important dispositional trait that may explain genetic influences on major depressive disorder/conduct disorder comorbidity, at least for boys. Models of major depressive disorder/conduct disorder comorbidity must simultaneously measure common and specific genetic and environmental factors for a full understanding of this phenomenon. Gender differences require specific research attention in dispositional factors and developmental progression.

Interactions between early parenting and a polymorphism of the child's dopamine transporter gene in predicting future child conduct disorder symptoms

Mounting evidence suggests that genetic risks for mental disorders often interact with the social environment, but most studies still ignore environmental moderation of genetic influences. The authors tested interactions between maternal parenting and the variable number tandem repeat (VNTR) polymorphism in the 3' untranslated region of the dopamine transporter gene in the child to increase understanding of gene-environment interactions involving early parenting. Participants were part of a 9-year longitudinal study of 4- to 6-year-old children who met criteria for attention-deficit/hyperactivity disorder (ADHD) and demographically matched controls. Maternal parenting was observed during standard mother-child interactions in Wave 1. The child's conduct disorder (CD) symptoms 5-8 years later were measured using separate structured diagnostic interviews of the mother and youth. Controlling for ADHD symptoms and child disruptive behavior during the mother-child interaction, there was a significant inverse relation between levels of both positive and negative parenting at 4-6 years and the number of later CD symptoms, but primarily among children with 2 copies of the 9-repeat allele of the VNTR. The significant interaction with negative parenting was replicated in parent and youth reports of CD symptoms separately.

Predictive validity of childhood oppositional defiant disorder and conduct disorder: implications for the DSM-V

Data are presented from 3 studies of children and adolescents to evaluate the predictive validity of childhood oppositional defiant disorder (ODD) and conduct disorder (CD) as defined in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV; American Psychiatric Association, 1994) and the International Classification of Diseases, Version 10 (ICD-10; World Health Organization, 1992). The present analyses strongly support the predictive validity of these diagnoses by showing that they predict both future psychopathology and enduring functional impairment. Furthermore, the present findings generally support the hierarchical developmental hypothesis in DSM-IV that some children with ODD progress to childhood-onset CD, and some youth with CD progress to antisocial personality disorder (APD). Nonetheless, they reveal that CD does not always co-occur with ODD, particularly during adolescence. Importantly, the present findings suggest that ICD-10 diagnostic criteria for ODD, which treat CD symptoms as ODD symptoms when diagnostic criteria for CD are not met, identify more functionally impaired children than the more restrictive DSM-IV definition of ODD. Filling this "hole" in the DSM-IV criteria for ODD should be a priority for the DSM-V. In addition, the present findings suggest that although the psychopathic trait of interpersonal callousness in childhood independently predicts future APD, these findings do not confirm the hypothesis that callousness distinguishes a subset of children with CD with an elevated risk for APD.

Higher-order genetic and environmental structure of prevalent forms of child and adolescent psychopathology

CONTEXT

It is necessary to understand the etiologic structure of child and adolescent psychopathology to advance theory and guide future research.

OBJECTIVE

To test alternative models of the higher-order structure of etiologic effects on 11 dimensions of child and adolescent psychopathology using confirmatory factor analyses of genetic and environmental covariances.

DESIGN

Representative sample of twins.

SETTING

Home interviews.

PARTICIPANTS

A total of 1571 pairs of 9- to 17-year-old twins.

MAIN OUTCOME MEASURES

Structured assessments of psychopathology using adult caregivers and youth as informants.

RESULTS

The best-fitting genetic model revealed that most genetic factors nonspecifically influence risk for either all 11 symptom dimensions or for dimensions of psychopathology within 1 of 2 broad domains. With some notable exceptions, dimension-specific genetic influences accounted for modest amounts of variance.

CONCLUSIONS

To inform theory and guide molecular genetic studies, an etiologic model is offered in which 3 patterns of pleiotropy are hypothesized to be the principal modes of genetic risk transmission for common forms of child and adolescent psychopathology. Some common environmental influences were found, but consistent with a "generalist genes, specialist environments" model, there was little sharing of environmental influences. This implies that prevalent dimensions of child and adolescent psychopathology mostly share their genetic liabilities but are differentiated by nonshared experiences.

Very early predictors of adolescent depression and suicide attempts in children with attention-deficit/hyperactivity disorder

CONTEXT

Major depression and dysthymia in adolescence are associated with substantial disability, need for mental health services, and risk for recurrence. Concrete suicidal ideation and attempts during adolescence are particularly associated with significant distress, morbidity, and risk for completed suicide.

OBJECTIVES

To test the hypothesis that young children with attention-deficit/hyperactivity disorder (ADHD) are at increased risk for depression and suicidal ideation and attempts during adolescence and to identify early predictors of which young children with ADHD are at greatest risk.

DESIGN

Prospective follow-up study.

SETTING

Chicago, Illinois, and Pittsburgh, Pennsylvania. Patients  A cohort of 125 children who met DSM-IV criteria for ADHD at 4 to 6 years of age and 123 demographically matched comparison children without ADHD were prospectively followed up in 7 structured diagnostic assessments of depression and suicidal behavior in assessment years 6 through 14, spanning 9 through 18 years of age.

MAIN OUTCOME MEASURES

DSM-IV criteria for depressive disorders and suicidal behavior.

RESULTS

Children with ADHD at 4 to 6 years of age were at greatly increased risk for meeting DSM-IV criteria for major depression or dysthymia (hazard ratio, 4.32) and for attempting suicide (hazard ratio, 3.60) through the age of 18 years relative to comparison children. There were marked variations in risk for these outcomes among children with ADHD, however. Within the ADHD group, children with each subtype of ADHD were at risk but for different adverse outcomes. Girls were at greater risk for depression and suicide attempts. Maternal depression and concurrent child emotional and behavior problems at 4 to 6 years of age predicted depression and suicidal behavior.

CONCLUSIONS

All subtypes of ADHD in young children robustly predict adolescent depression and/or suicide attempts 5 to 13 years later. Furthermore, female sex, maternal depression, and concurrent symptoms at 4 to 6 years of age predict which children with ADHD are at greatest risk for these adverse outcomes. Identifying high-risk young children with ADHD sets the stage for early prevention trials to reduce risk for later depression and suicidal behavior.

All in the Family: Comparing Siblings to Test Causal Hypotheses Regarding Environmental Influences on Behavior

Psychologists in both basic and applied fields are keenly interested in the environmental influences that shape our lives. Therefore, researchers test causal hypotheses to construct models of environmental influences that can withstand attempts at refutation. Randomized experiments provide the strongest tests of causal hypotheses, but are not always feasible and their assumptions cannot always be met. In such cases, a number of quasi-experimental research designs can be used to substantially reduce confounding in tests of causal hypotheses. Sibling-comparison designs provide robust quasi-experimental tests of causal environmental hypotheses, but they are underused in psychology in spite of their power, feasibility, and convenience.

Modification of the frequency of descriptive adjectives in the speech of Head Start children through modeling without reinforcement

Children enrolled in a Head Start program were instructed to describe the contents of each of four boxes of toys. After the subject's initial description (baseline), the experimenter (model) described the contents of three boxes of different toys in alternation with the subject's descriptions. For one group, the experimenter used descriptive adjectives in his descriptions. In a second group, the experimenter used no adjectives of any kind. A marked increase in the frequency of descriptive adjectives was observed during the first description after modeling in the first group. This increase was maintained in successive descriptions at approximately the frequency used by the experimenter. Frequency of descriptive adjectives remained at zero or decreased in the second group.

Control of an obscene "verbal tic" through timeout in an elementary school classroom

A classroom teacher modified the behavior of a 10-yr-old student who had a high rate of obscene vocalizations accompanied by facial twitches. In the first phase, the subject was instructed to repeat rapidly the most frequent obscene word in four daily 15-min sessions. This procedure reduced the frequency of obscene vocalizations, but not to an acceptable level. Subsequently, the teacher was able effectively to control the target behavior using a timeout procedure.

Effects of intermittent modelling on observational learning

A large research literature suggests that modelling in the absence of reinforcement for either the model's or the observer's behavior is a potent source of social learning. This literature is based entirely, however, on experiments using models that always display the critical behaviors. It is possible, therefore, that results obtained in these experiments would not generalize to natural settings in which modelling is intermittent. The effects of intermittent modelling were examined using three groups of 15 four- and five-year-old children. Male and female children from middle-income families were individually exposed to an adult model who alternated descriptions of pictures of common objects. With one group, the model used no descriptive adjectives (color or number) in her descriptions after baseline; she used descriptive adjectives with 50% of the pictures with a second group, and 100% of the pictures with a third. Analyses of the data showed that the children substantially increased their use of descriptive adjectives in both modelling groups, but not in the no-modelling group. The fact that there were no significant differences between the 50% and 100% modelling groups suggests that results obtained in studies using consistent modelling can be generalized to natural settings.

Modification of deficits in reading for comprehension

Subjects were asked to read a passage orally and then to answer questions about the passage. When praise and pennies were given for correct answers, the percentage of correct answers increased in two sixth-grade subjects whose reading for comprehension was tested to be 2 yr below grade level. The behavior of these subjects was compared to that of two subjects whose reading for comprehension was tested to be on grade level. Although no evidence for changes in the accuracy of answering comprehension questions is found in the previous literature, the percentage of correct answers in the children with deficits increased to approximately the same level as the children tested to be on grade level.

A method for combining occurrence and nonoccurrence interobserver agreement scores

Various statistics have been proposed as standard methods for calculating and reporting interobserver agreement scores. The advantages and disadvantages of each have been discussed in this journal recently but without resolution. A formula is presented that combines separate measures of occurrence and nonoccurrence percentages of agreement, with weight assigned to each measure, varying according to the observed rate of behavior. This formula, which is a modification of a formula proposed by Clement (1976), appears to reduce distortions due to "chance" agreement encountered with very high or low observed rates of behavior while maintaining the mathematical and conceptual simplicity of the conventional method for calculating occurrence and nonoccurrence agreement.