Biomedical subjects

Adrian Angold

Publications and source records attributed to Adrian Angold.

At least 19 recordsLinked to original sources

PubMed2006

Bayesian semi-parametric ROC analysis.

This paper describes a semi-parametric Bayesian approach for estimating receiver operating characteristic (ROC) curves based on mixtures of Dirichlet process priors (MDP). We address difficulties in modelling the underlying distribution of screening scores due to non-normality that may lead to incorrect choices of diagnostic cut-offs and unreliable estimates of prevalence of the disease. MDP is a robust tool for modelling non-standard diagnostic distributions associated with imperfect classification of an underlying diseased population, for example, when a diagnostic test is not a gold standard. For posterior computations, we propose an efficient Gibbs sampling framework based on a finite-dimensional approximation to MDP. We show, using both simulated and real data sets, that MDP modelling for ROC curve estimation closely parallels the frequentist kernel density estimation (KDE) approach.

Adolescent↗

PubMed2006

Prevalence, clinical correlates, and longitudinal course of severe mood dysregulation in children.

BACKGROUND: Controversy concerning the diagnosis of pediatric bipolar disorder (BD) has focused attention on children with chronic irritability and hyperarousal. This syndrome has been called the "broad BD phenotype" or severe mood dysregulation (SMD). This study examines prevalence, concurrent Axis I diagnoses, and longitudinal outcome of SMD in an epidemiologic sample. METHODS: Data were drawn from the Great Smoky Mountains Study, a longitudinal epidemiological study. Items from the Child and Adolescent Psychiatric Assessment were used to generate SMD criteria. RESULTS: Among 1420 children, the lifetime prevalence of SMD in children ages 9-19 was 3.3%. Most (67.7%) SMD youth had an Axis I diagnosis, most commonly attention-deficit/hyperactivity disorder (26.9%), conduct disorder (25.9%), and/or oppositional defiant disorder (24.5%). In young adulthood (mean age 18.3 +/- 2.1 years), youth who met criteria for SMD in the first wave (mean age 10.6 +/- 1.4 years) were significantly more likely to be diagnosed with a depressive disorder (odds ratio 7.2, confidence interval 1.3-38.8, p = .02) than youth who never met criteria for SMD. CONCLUSIONS: Severe mood dysregulation is relatively common in childhood and predicts risk for early adulthood depressive disorders. Research should continue to explore the course of illness in children with SMD.

Adolescent↗

PubMed2006

Proximal psychiatric risk factors for suicidality in youth: the Great Smoky Mountains Study.

CONTEXT: Psychiatric disorder is a major risk factor for suicidality but has poor positive predictive value. OBJECTIVES: To characterize proximal risks for suicidality associated with anxiety, depressive, disruptive behavior, and substance use disorders, and to test whether there are critical combinations of disorders that discriminate at-risk youth independent of severity of psychopathology. DESIGN: The Great Smoky Mountains Study, a representative sample of children and adolescents aged 9 to 16 years from the southeastern United States. Subjects and their parents were interviewed on multiple occasions from 1993 to 2000 about the subjects' recent psychiatric and suicidal history. SETTING: An epidemiological sample of youth. PARTICIPANTS: The sample included 1420 individual subjects with 6676 records across 8 waves of data collection. MAIN OUTCOME MEASURES: Wanting to die, suicidal ideation, suicide plans, or suicide attempt during the past 3 months. RESULTS: Eleven broad psychiatric profiles discriminated suicidal youth. Risk was greatest in association with current depression plus anxiety (specifically GAD [generalized anxiety disorder]) (odds ratio, 468.53) or depression plus a disruptive disorder (primarily ODD [oppositional-defiant disorder]) (odds ratio, 222.94). Unless comorbid, anxiety and substance use disorders were not proximally associated with suicidality. The severity of symptom-related impairment and, in some cases, total symptom load explained risk associated with all psychiatric profiles except depression plus anxiety, specifically GAD (adjusted odds ratio, 50.16). Severity of impairment and poverty defined by federal guidelines for families were both independent risk factors, irrespective of psychiatric profile. Suicidal youth without diagnosable disorders had subthreshold (mostly disruptive) disorders, disabling relationship difficulties, or psychiatric symptoms without associated impairment. CONCLUSIONS: Severity of symptom-related impairment and total symptom load explained most of the risk for suicidality associated with current psychiatric disorders. Only depression plus GAD discriminated at-risk youth independent of severity of psychopathology.

Adolescent↗

PubMed2006

Puberty and depression.

Unipolar depression only becomes more common in girls than boys after the age of 13, as a result of an increased incidence of depressive episodes in girls at that time. This article reviews evidence that links multiple dimensions of maturation in the hypothalamo-pituitary-gonadal axis with this phenomenon. Effects of developmental status and timing have been implicated, but few studies have deployed either the measurement strategies or the statistical power needed to provide a satisfactory answer to the question regarding which components of puberty are most responsible.

Adolescent↗

PubMed2006

10-year research update review: the epidemiology of child and adolescent psychiatric disorders: II. Developmental epidemiology.

OBJECTIVE: To describe the growth of developmental epidemiology in the past decade and to illustrate it with examples of recent studies. METHOD: A review of publications on developmental epidemiology in the past 10 years and a discussion of some key examples. RESULTS: The authors describe how the interaction between developmental psychopathology and psychiatric epidemiology has produced developmental epidemiology, the study of patterns of distribution of psychiatric disorders in time as well as in space. They give two examples of the kinds of questions that developmental epidemiology can help to answer: (1) Is the prevalence of autism increasing? Does the use of vaccines explain the increase? (2) Is there an epidemic of child and adolescent depression? Finally, they describe two areas of science that are beginning to inform developmental epidemiology: molecular genetics and the use of biological measures of stress. CONCLUSIONS: While child and adolescent psychiatric epidemiology continues, as described in the first of these reviews, to address questions of prevalence and burden, it has also expanded into new areas of research in the past decade. In the next decade, longitudinal epidemiological data sets with their rich descriptive data on psychopathology and environmental risk over time and the potential to add biological measures will provide valuable resources for research into gene-environment correlations and interactions.

Adolescent↗

PubMed2006

Test-Retest Reliability of the Preschool Age Psychiatric Assessment (PAPA).

OBJECTIVE: To examine the test-retest reliability of a new interviewer-based psychiatric diagnostic measure (the Preschool Age Psychiatric Assessment) for use with parents of preschoolers aged 2 to 5 years. METHOD: A total of 1,073 parents of children attending a large pediatric clinic completed the Child Behavior Checklist 1 1/2-5. For 18 months, 193 parents of high scorers and 114 parents of low scorers were interviewed on two occasions an average of 11 days apart. RESULTS: Estimates of diagnostic reliability were very similar to those obtained from interviews with parents of older children and adults, with kappas ranging from 0.36 to 0.79. Test-retest intraclass correlations for DSM-IV syndrome scale scores ranged from 0.56 to 0.89. There were no significant differences in reliability by age, sex, or race (African American versus non-African American). CONCLUSIONS: The Preschool Age Psychiatric Assessment provides a reasonably reliable standardized measure of DSM-IV psychiatric symptoms and disorders in preschoolers for use in both research and clinical service evaluations of preschoolers as young as 2 years old.

Child Behavior Disorders↗

PubMed2006

A comparison of pure and comorbid CD/ODD and depression.

BACKGROUND: We studied the symptomatology of conduct/oppositional defiant disorder and major depression/dysthymic disorder in 'pure' and comorbid presentations. METHOD: The sample comprised 382 children of 8 to 17 years of age attending for psychiatric outpatient consultation. Ninety-two had depressive disorders without conduct disorders, 165 conduct disorder or oppositional defiant disorder without depressive disorders and 125 had both. RESULTS: In general, there were few differences in the distributions of the symptoms of shared disorders between the pure and the comorbid groups. Comorbidity accentuated depressive and emotional symptoms and functional impairment. After controlling for the presence of other disorders and severity of symptoms, comorbid children were more globally impaired than the pure conduct group and more impaired than the pure depressive group in school, the home, and in relationships with other people. CONCLUSIONS: The clinical presentations of 'pure' and comorbid depressive and conduct disorders are similar. Differences found in phenomenology and in functional impairment between the groups have implications for treatment planning and for nosology.

Adolescent↗

PubMed2006

Is there an epidemic of child or adolescent depression?

BACKGROUND: Both the professional and the general media have recently published concerns about an 'epidemic' of child and adolescent depression. Reasons for this concern include (1) increases in antidepressant prescriptions, (2) retrospective recall by successive birth cohorts of adults, (3) rising adolescent suicide rates until 1990, and (4) evidence of an increase in emotional problems across three cohorts of British adolescents. METHODS: Epidemiologic studies of children born between 1965 and 1996 were reviewed and a meta-analysis conducted of all studies that used structured diagnostic interviews to make formal diagnoses of depression on representative population samples of participants up to age 18. The effect of year of birth on prevalence was estimated, controlling for age, sex, sample size, taxonomy (e.g., DSM vs. ICD), measurement instrument, and time-frame of the interview (current, 3 months, 6 months, 12 months). RESULTS: Twenty-six studies were identified, generating close to 60,000 observations on children born between 1965 and 1996 who had received at least one structured psychiatric interview capable of making a formal diagnosis of depression. Rates of depression showed no effect of year of birth. There was little effect of taxonomy, measurement instrument, or time-frame of interview. The overall prevalence estimates were: under 13, 2.8% (standard error (SE) .5%); 13-18 5.6% (SE .3%); 13-18 girls: 5.9% (SE .3%); 13-18 boys: 4.6% (SE .3%). CONCLUSIONS: When concurrent assessment rather than retrospective recall is used, there is no evidence for an increased prevalence of child or adolescent depression over the past 30 years. Public perception of an 'epidemic' may arise from heightened awareness of a disorder that was long under-diagnosed by clinicians.

Adolescent↗

PubMed2005

Application of Bayesian inference using Gibbs sampling to item-response theory modeling of multi-symptom genetic data.

Several "genetic" item-response theory (IRT) models are fitted to the responses of 1086 adolescent female twins to the 33 multi-category item Mood and Feeling Questionnaire relating to depressive symptomatology in adolescence. A Markov-chain Monte Carlo (MCMC) algorithm is used within a Bayesian framework for inference using Gibbs sampling, implemented in the program WinBUGS 1.4. The final model incorporated separate genetic and non-shared environmental traits ("A and E") and item-specific genetic effects. Simpler models gave markedly poorer fit to the observations judged by the deviance information criterion (DIC). The common genetic factor showed major loadings on melancholic items, while the environmental factor loaded most highly on items relating to self-deprecation. The MCMC approach provides a convenient and flexible alternative to Maximum Likelihood for estimating the parameters of IRT models for relatively large numbers of items in a genetic context. Additional benefits of the IRT approach are discussed including the estimation of latent trait scores, including genetic factor scores, and their sampling errors.

Adolescent↗

PubMed2005

The developmental epidemiology of anxiety disorders: phenomenology, prevalence, and comorbidity.

This article argues that the quality of diagnostic tools used to measure anxiety disorders in children and adolescents has improved enormously in the past few years. As a result, prevalence estimates are less erratic, understanding of comorbidity is increasing, and the role of impairment as a criterion for "caseness" is considered more carefully. Several of the instruments developed for epidemiologic research are now being used in clinical settings. Further integration of laboratory methods and clinical and epidemiologic ideas will benefit children with anxiety disorders and their families.

Adolescent↗

PubMed2005

10-year research update review: the epidemiology of child and adolescent psychiatric disorders: I. Methods and public health burden.

OBJECTIVE: To review recent progress in child and adolescent psychiatric epidemiology in the area of prevalence and burden. METHOD: The literature published in the past decade was reviewed under two headings: methods and findings. RESULTS: Methods for assessing the prevalence and community burden of child and adolescent psychiatric disorders have improved dramatically in the past decade. There are now available a broad range of interviews that generate DSM and ICD diagnoses with good reliability and validity. Clinicians and researchers can choose among interview styles (respondent based, interviewer based, best estimate) and methods of data collection (paper and pencil, computer assisted, interviewer or self-completion) that best meet their needs. Work is also in progress to develop brief screens to identify children in need of more detailed assessment, for use by teachers, pediatricians, and other professionals. The median prevalence estimate of functionally impairing child and adolescent psychiatric disorders is 12%, although the range of estimates is wide. Disorders that often appear first in childhood or adolescence are among those ranked highest in the World Health Organization's estimates of the global burden of disease. CONCLUSIONS: There is mounting evidence that many, if not most, lifetime psychiatric disorders will first appear in childhood or adolescence. Methods are now available to monitor youths and to make early intervention feasible.

Adolescent↗

PubMed2005

Defining oppositional defiant disorder.

BACKGROUND: ICD-10 and DSM-IV include similar criterial symptom lists for conduct disorder (CD) and oppositional defiant disorder (ODD), but while DSM-IV treats each list separately, ICD-10 considers them jointly. One consequence is that ICD-10 identifies a group of children with ODD subtype who do not receive a diagnosis under DSM-IV. METHODS: We examined the characteristics of this group of children using the Great Smoky Mountains Study of children in the community aged 9-16. This study provided child and parent reports of symptoms and psychosocial impairment assessed with standardised diagnostic interviews. RESULTS: Children who received an ICD-10 diagnosis but not a DSM-IV diagnosis showed broadly similar levels of psychiatric comorbidity, delinquent activity and psychosocial impairment to those who met DSM-IV criteria in both cross-sectional and longitudinal analyses. CONCLUSIONS: These results indicate that DSM-IV excludes from diagnosis children who receive an ICD-10 diagnosis of CD (ODD sub-type), and who are substantially disturbed. Methods of redressing this situation are considered.

Adolescent↗

PubMed2004

Effects of age at first substance use and psychiatric comorbidity on the development of substance use disorders.

In this paper, we examine the effects of age at first substance use, and history of psychiatric disorders, on the development of substance use disorder (SUD) by age 16. We use a prospective, longitudinal design to disaggregate the effects of age at first use and time since first use on the development of adolescent SUD. Second, we test the hypothesis that adolescent SUD is an unlikely progression from early substance use unless children also show other early conduct problems. A population sample of 1,420 children from the Great Smoky Mountains Study (GSMS) was assessed annually between ages 9 and 16. Logistic regression models were applied within the hierarchical Bayesian framework, where the covariate effects were described by time-varying parameters having a first-order auto-regressive prior distribution. Posterior analyses based on a Gibbs sampling approach revealed that, controlling for years of exposure, the risk of transition to SUD increased with age at onset for onsets before age 13, but began to fall for onset at 14. Among users, use alone, without early conduct problems, led to a 11% prevalence of SUD by age 16. Past conduct disorder (CD) had a strong additive effect at ages 13-15, but at age 16, when substance use and abuse became more normative, the excess risk from prior CD decreased. Boys, but not girls, with a history of depression were at increased risk of SUD. Anxiety increased the risk of SUD in girls at age 16, but not before that. Results only partially support the study hypothesis; early use was a major predictor of adolescent SUD even in the absence of CD.

Adolescent↗

PubMed2004

Testosterone, antisocial behavior, and social dominance in boys: pubertal development and biosocial interaction.

BACKGROUND: Studies linking testosterone and antisocial behavior in humans have produced mixed results. Adolescence offers a promising period to study this relationship; circulating testosterone increases dramatically in boys during puberty, and antisocial behavior increases during the same period. METHODS: Our analyses were based on boys aged 9-15 years who were interviewed during the first three waves of the Great Smoky Mountains Study. Measures included interview assessment of DSM-IV conduct disorder (CD) symptoms and diagnosis, blood spot measurement of testosterone, Tanner staging of pubertal development, and assessment of leadership behaviors and peer deviance. RESULTS: The adolescent rise in CD was primarily attributable to an increase in nonphysically aggressive behaviors. Increasing levels of circulating testosterone and association with deviant peers contributed to these age trends. There was no evidence that physical aggression was related to high testosterone. Evidence of biosocial interactions was identified; testosterone was related to nonaggressive CD symptoms in boys with deviant peers and to leadership in boys with nondeviant peers. CONCLUSIONS: The results are consistent with the hypothesis that testosterone relates to social dominance, with the assumption that behaviors associated with dominance differ according to social context.

Adolescent↗

PubMed2004

Informant disagreement for separation anxiety disorder.

OBJECTIVE: To characterize informant disagreement for separation anxiety disorder (SAD). METHOD: The sample comprised 2,779 8- to 17-year-old twins from a community-based registry. Children and their parents completed a personal interview about the child's psychiatric history. Parents completed a personal interview about their own psychiatric history and a questionnaire about their marital relationship. RESULTS: Informant agreement for SAD ranged between chance and extremely poor. Most cases of SAD were diagnosed by interview with only one informant. SAD diagnosed only by child interview was associated with an increased odds of father-rated oppositional defiant disorder, and vice versa. SAD diagnosed only by parent interview was predicted by the parental informant's history of antisocial personality disorder. SAD diagnosed only by paternal interview was also predicted by mother-rated marital conflict and dissatisfaction. CONCLUSIONS: Parents and children rarely agree about the presence of any level of child separation anxiety. A symptom "or-rule" mostly indexes diagnoses based on interview with only one informant, but the relative validity of such diagnoses remains unclear.

Adolescent↗

PubMed2004

Genetic and environmental influences on the relative timing of pubertal change.

A multicategory item-response theory model was developed to characterize developmental changes in three items relating to the assessment of puberty in adolescent twin girls and boys. The model allowed for the fixed effects of age on probability of endorsing the responses and for the random effects of individual differences on the timing of pubertal changes relative to chronological age. In girls, the model was applied three-wave data on twin pairs (N = 414 female monozygotic [MZ] and 197 female dizygotic [DZ] pairs) and female twins from boy-girl pairs (N = 300 twins) from the Virginia Twin Study of Adolescent Behavioral Development. In boys, the data comprised 318 MZ and 185 DZ pairs and 297 male twins from boy-girl pairs. A total of 3172 and 2790 individual twin assessments were available in girls and boys, respectively, spanning ages 8-17 years. The availability of twin data allows the contributions of genes, the shared environment and individual unique environmental experiences to be resolved in the relative timing of pubertal changes. Parameters of the mixed model including fixed effects of age and random effects of genes and environment were estimated by Markov Chain Monte Carlo simulations using the BUGS algorithm for Gibbs sampling. The estimated standard deviation of random differences in the timing of puberty relative to age was 0.96 years in girls and 1.01 years in boys. The estimated intraclass correlations for the relative timing of pubertal changes were 0.99 +/-0.01 in MZ girls, 0.52 +/-0.02 in DZ girls, 0.88 +/-0.04 in MZ boys and 0.44+/-0.02 in DZ boys, indicating a very large contribution of genetic factors to the relative timing of pubertal change in both sexes. Additive genetic factors account for an estimated 96.3+/-3.3% of the total variance in random effects in girls and 88.0+/-3.6% in boys. Shared environmental influences account for 3.6+/-3.4% in girls and 0% in boys. In girls, nonshared environmental effects explain 0.1+/-0.1% of the total residual variance. The comparable figure in boys is 12.0+/-3.6%.

Adolescent↗

PubMed2003

Relationships between poverty and psychopathology: a natural experiment.

CONTEXT: Social causation (adversity and stress) vs social selection (downward mobility from familial liability to mental illness) are competing theories about the origins of mental illness. OBJECTIVE: To test the role of social selection vs social causation of childhood psychopathology using a natural experiment. DESIGN: Quasi-experimental, longitudinal study. POPULATION AND SETTING: A representative population sample of 1420 rural children aged 9 to 13 years at intake were given annual psychiatric assessments for 8 years (1993-2000). One quarter of the sample were American Indian, and the remaining were predominantly white. Halfway through the study, a casino opening on the Indian reservation gave every American Indian an income supplement that increased annually. This increase moved 14% of study families out of poverty, while 53% remained poor, and 32% were never poor. Incomes of non-Indian families were unaffected. MAIN OUTCOME MEASURES: Levels of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, psychiatric symptoms in the never-poor, persistently poor, and ex-poor children were compared for the 4 years before and after the casino opened. RESULTS: Before the casino opened, the persistently poor and ex-poor children had more psychiatric symptoms (4.38 and 4.28, respectively) than the never-poor children (2.75), but after the opening levels among the ex-poor fell to those of the never-poor children, while levels among those who were persistently poor remained high (odds ratio, 1.50; 95% confidence interval, 1.08-2.09; and odds ratio, 0.91; 95% confidence interval, 0.77-1.07, respectively). The effect was specific to symptoms of conduct and oppositional defiant disorders. Anxiety and depression symptoms were unaffected. Similar results were found in non-Indian children whose families moved out of poverty during the same period. CONCLUSIONS: An income intervention that moved families out of poverty for reasons that cannot be ascribed to family characteristics had a major effect on some types of children's psychiatric disorders, but not on others. Results support a social causation explanation for conduct and oppositional disorder, but not for anxiety or depression.

Adolescent↗

PubMed2003

Maternal smoking during pregnancy and risk to boys' conduct disturbance: an examination of the causal hypothesis.

BACKGROUND: We undertook this study to determine whether the widely replicated link between maternal smoking and conduct disturbance (Cd) is better explained by a model of direct causation or of mother-offspring transmission of a latent Cd variable. METHODS: Family data collected on 538 adolescent twin boys from the Virginia Twin Study of Adolescent Behavioral Development (VTSABD) was used to compare two alternative models: 1) a model composed of a latent transmissible factor that influences mother's juvenile conduct symptoms, smoking during pregnancy, and subsequent Cd and smoking in her adolescent boys; and 2) a model specifying a direct causal path from mother's smoking to child Cd. RESULTS: The maternal-offspring transmission model fit the data as well as a model specifying a direct causal path from maternal smoking to child Cd. CONCLUSIONS: Our results suggest that the association between maternal smoking during pregnancy and boys' Cd symptoms may be attributed to the transmission of a latent Cd factor and not to a direct effect of the smoking. Our results challenge previous findings of a direct effect of prenatal smoke exposure on risk to Cd once other etiologic factors are considered.

Adolescent↗