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Background: Prenatal and perinatal factors have been linked to affective disorders. We therefore undertook an exploratory study to determine whether prenatal exposure to severe famine was associated with an increased risk of affective disorders.Method: Monthly birth cohorts that were exposed and unexposed to the Dutch Hunger Winter of 1944-45 were identified. The cumulative incidences of affective psychoses and neurotic depression (ICD-9 criteria) were compared between exposed and unexposed cohorts during each trimester of gestation.Results: The relative risk (RR) of affective psychosis (broad and restricted definitions) among persons exposed to famine during the second trimester was significantly increased (broad: RR (95% confidence interval) = 1.62 (1.19, 2.20); restricted: 1.59 (1.14, 2.21)). Separate analysis by gender showed a significant association among males (broad: 2.26 (1.43, 3.57); restricted: 2.40 (1.49, 3.89), but not females (broad: 1.28 (0.84, 1.94); restricted: 1.17 (0.73, 1.76)). The risk of neurotic depression was not increased after prenatal famine exposure.Conclusions: These results suggest a possible relationship between prenatal famine during the second trimester and affective psychosis, lending plausibility to reports that have associated affective psychoses with prenatal exposures. Further studies of this relationship are warranted. [ABSTRACT FROM AUTHOR]

Introduction: Evidence from high-income countries demonstrates effectiveness of early intervention services (EIS) for people with First Episode Psychosis (FEP). In the US, OnTrackNY, a type of EIS, has been successfully implemented across many communites. No Latin-American country offers universal access to EIS for FEP, with the partial exception of Chile where FEP policies don't conform to recently established evidence-based approaches. To apply OnTrackNY in Chile, adaptations to this new context are required. Objectives: Identify stakeholder views on strengths and barriers associated with implementing OnTrackNY in Chile. Methods: Semi-structured qualitative interviews were conducted in three Community Mental Health Centers (CMHC) in two regions across stakeholder groups: policy makers (n=5), CMHC Health Managers/Directors (n=4), mental health professionals (n=8). Conducted two focus groups with clients (n=13) and families (n=13). Stakeholders views about three areas were examined: Current FEP services in Chile; OnTrack implementation in Chile; and OnTrack training approach to support implementation. Results: Stakeholders shared consensus regarding strengths and barriers about each category. Current FEP services were viewed as lacking coordinated outreach and referral, promoting stigma and using a more traditional medical model. Stakeholders expressed strong acceptance of OnTrack model as it will help shift FEP services to a more recovery-oriented, patient-centered approach. Views about training identified important barriers including lack of incentives and limited time for training. Conclusions: Stakeholders consider OnTrack as an important approach to transform FEP services in Chile using a more recovery-oriented approach. Although some concerns in implementation logistics were identified, there appears to be strong support for On Track's implementation with the appropriate adaptations. Disclosure: This project is funded by National Institute of Mental Health (R01MH115502: Contact PI: Alvarado, Multi-PIs: Cabassa, Dixon, Susser). [ABSTRACT FROM AUTHOR]

The article focuses on evidence-based psychotherapeutic interventions in the community care of schizophrenia in Great Britain. The authors presented evidence for community mental health teams and reviewed findings on types of psychotherapeutic treatment that might delivered by such teams. Other psychological teams that might be effective in the community are also discussed.

The emerging ‘life-course cohorts’ are a powerful new resource in epidemiology. These are cohorts followed from early gestation until the end of life.1 We shall deal in turn with the history of this phenomenon, the implications for epidemiological research and the consequences for the field of epidemiology itself. [ABSTRACT FROM AUTHOR]

Focuses on the psychosocial and ethical issues related to AIDS. Benefits of parent disclosure interview; Psychometric properties of Impact of Weight Loss Scale, a subjective measure of perceived weight loss; Details on the coping ability among HIV negative and HIV positive female injection drug users.

Abstract Background The Norwegian Mother and Child Cohort Study (MoBa) is a nation-wide population-based pregnancy cohort initiated in 1999, comprising more than 108.000 pregnancies recruited between 1999 and 2008. In this study we evaluated the feasibility of integrating RNA analyses into existing MoBa protocols. We compared two different blood RNA collection tube systems – the PAXgene™ Blood RNA system and the Tempus™ Blood RNA system - and assessed the effects of suboptimal blood volumes in collection tubes and of transportation of blood samples by standard mail. Endpoints to characterize the samples were RNA quality and yield, and the RNA transcript stability of selected genes. Findings High-quality RNA could be extracted from blood samples stabilized with both PAXgene and Tempus tubes. The RNA yields obtained from the blood samples collected in Tempus tubes were consistently higher than from PAXgene tubes. Higher RNA yields were obtained from cord blood (3 – 4 times) compared to adult blood with both types of tubes. Transportation of samples by standard mail had moderate effects on RNA quality and RNA transcript stability; the overall RNA quality of the transported samples was high. Some unexplained changes in gene expression were noted, which seemed to correlate with suboptimal blood volumes collected in the tubes. Temperature variations during transportation may also be of some importance. Conclusions Our results strongly suggest that special collection tubes are necessary for RNA stabilization and they should be used for establishing new biobanks. We also show that the 50,000 samples collected in the MoBa biobank provide RNA of high quality and in sufficient amounts to allow gene expression analyses for studying the association of disease with altered patterns of gene expression.

Abstract Background The WHO Multiple Exposures Multiple Effects (MEME) framework identifies community contextual variables as central to the study of childhood health. Here we identify multiple domains of neighborhood context, and key variables describing the dimensions of these domains, for use in the National Children’s Study (NCS) site in Queens. We test whether the neighborhoods selected for NCS recruitment, are representative of the whole of Queens County, and whether there is sufficient variability across neighborhoods for meaningful studies of contextual variables. Methods Nine domains (demographic, socioeconomic, households, birth rated, transit, playground/greenspace, safety and social disorder, land use, and pollution sources) and 53 indicator measures of the domains were identified. Geographic information systems were used to create community-level indicators for US Census tracts containing the 18 study neighborhoods in Queens selected for recruitment, using US Census, New York City Vital Statistics, and other sources of community-level information. Mean and inter-quartile range values for each indicator were compared for Tracts in recruitment and non-recruitment neighborhoods in Queens. Results Across the nine domains, except in a very few instances, the NCS segment-containing tracts (N = 43) were not statistically different from those 597 populated tracts in Queens not containing portions of NCS segments; variability in most indicators was comparable in tracts containing and not containing segments. Conclusions In a diverse urban setting, the NCS segment selection process succeeded in identifying recruitment areas that are, as a whole, representative of Queens County, for a broad range of community-level variables.

Background. The relationship between prenatal tobacco exposure and hyperactivity remains controversial. To mitigate limitations of prior studies, we used a strategy involving comparison of maternal and paternal smoking reports in a historical sample where smoking during pregnancy was common. Method. Data were drawn from a longitudinally followed subsample of the Child Health and Development Study (n = 1752), a population-based pregnancy cohort ascertained in 1961-1963 in California. Maternal prenatal smoking was common (33.4%). Maternal and paternal smoking patterns were assessed at three time points by mother report. Hyperactivity was assessed at the mean of age of 10 years based on mother report to a personality inventory. Results. Unadjusted, maternal smoking during pregnancy was associated with offspring hyperactivity [β=0.22, 95% confidence interval (CI) 0.11-0.33] and, to a similar degree, when the father smoked (β=0.18, 95% CI 0.07-0.30). After adjustment, maternal smoking remained robustly predictive of offspring hyperactivity (β=0.25, 95% CI 0.09-0.40) but father smoking was not (β=0.02, 95% CI -0.20 to 0.24). When examined among the pairs matched on propensity score, mother smoking was robustly related to offspring hyperactivity whether the father smoked (β=0.26, 95% CI 0.03-0.49) or did not smoke (β=0.30, 95% CI 0.04-0.57). By number of cigarettes, associations with hyperactivity were present for 10-19 and 20+ cigarettes per day among mothers. Conclusions. In a pregnancy cohort recruited in a time period in which smoking during pregnancy was common, we document associations between prenatal smoking exposure and offspring hyperactivity. Novel approaches to inferring causality continue to be necessary in describing the potential adverse consequences of prenatal smoking exposure later in life. [ABSTRACT FROM AUTHOR]

In the Dutch Hunger Winter at the end of World War II a combination of circumstances created the conditions of a natural experiment. Unlike other famines, the Dutch famine struck at a precisely circumscribed time and place, and in a society able to document the timing and severity of the nutritional deprivation as well as the effects on fertility and health. Because the Dutch maintained comprehensive military and health records, it was possible to compare the incidence of neurodevelopmental disorders in adulthood for birth cohorts exposed versus those unexposed to prenatal famine. We have conducted several studies guided by the hypothesis that prenatal micronutrient deficiencies can cause neurodevelopmental schizophrenia or related personality disorders. In this paper we shall summarize our previous work and combine the outcome data of the different studies. Early prenatal famine was found to be specifically and robustly associated with each of three conditions: (1) congenital anomalies of the central nervous system, (2) schizophrenia, and (3) schizophrenia spectrum personality disorders. We found that the greatest increase in the risk of schizophrenia spectrum disorder- schizophrenia plus spectrum personality disorder- occurred among males born in the famine cities in December 1945 (relative risk = 2.7; 95% confidence interval = 1.5-5.1). Persons born in December 1945 were generally conceived at the absolute peak of the famine (March-April 1945). In the hope that the associations we have found may offer clues to the aetiology of schizophrenia, we are currently tracing and examining the cases of schizophrenia after prenatal exposure to famine. [ABSTRACT FROM AUTHOR]

Release from prison is a vulnerable period, especially for people with severe mental illness. Critical Time Intervention (CTI) can be effective in improving service access and reducing negative outcomes. Nested within a randomised controlled trial of CTI, qualitative interviews were conducted with trial participants in both intervention (CTI) and treatment as usual (TAU) arms, CTI managers delivering the intervention and associated professionals. Data were analysed using a framework approach. Four themes were identified: uncertainty about post-release plans; inadequate housing provision; support during transition; and continuity of care. Interviewees shared common concerns about transition into the community but CTI participants felt less anxious about release and reported receiving more support with housing, access to services and community reintegration than during previous periods of incarceration. Professionals raised concerns about the time-limited nature of CTI and the impact of austerity measures on the availability of support following CTI. Implications for service delivery will be discussed. [ABSTRACT FROM AUTHOR]

Purpose: There is considerable variation in epidemiology and clinical course of psychotic disorders across social and geographical contexts. To date, very little data are available from low- and middle-income countries. In sub-Saharan Africa, most people with psychoses remain undetected and untreated, partly due to lack of formal health care services. This study in rural South Africa aimed to investigate if it is possible to identify individuals with recent-onset psychosis in collaboration with traditional health practitioners (THPs).Methods: We developed a strategy to engage with THPs. Fifty THPs agreed to collaborate and were asked to refer help-seeking clients with recent-onset psychosis to the study. At referral, the THPs rated probability of psychosis ("maybe disturbed" or "disturbed"). A two-step diagnostic procedure was conducted, including the self-report Community Assessment of Psychic Experiences (CAPE) as screening instrument, and a semi-structured interview using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN). Accuracy of THP referrals, and test characteristics of the THP rating and the CAPE were calculated.Results: 149 help-seeking clients were referred by THPs, of which 44 (29.5%) received a SCAN DSM-IV diagnosis of psychotic disorder. The positive predictive value of a THP "disturbed" rating was 53.8%. Test characteristics of the CAPE were poor.Conclusion: THPs were open to identifying and referring individuals with possible psychosis. They recognized "being disturbed" as a condition for which collaboration with formal psychiatric services might be beneficial. By contrast, the CAPE performed poorly as a screening instrument. Collaboration with THPs is a promising approach to improve detection of individuals with recent-onset psychosis in rural South Africa. [ABSTRACT FROM AUTHOR]

BackgroundMaternal exposures to fever and infections in pregnancy have been linked to subsequent psychiatric morbidity in the child. This study examined whether fever and common infections in pregnancy were associated with psychosis-like experiences (PLEs) in the child.MethodsA longitudinal study of 46 184 children who participated in the 11-year follow-up of the Danish National Birth Cohort was conducted. Pregnant women were enrolled between 1996 and 2002 and information on fever, genitourinary infections, respiratory tract infection, and influenza-like illness during pregnancy was prospectively collected in two interviews during pregnancy. PLEs were assessed using the seven-item Adolescent Psychotic-Like Symptom Screener in a web-based questionnaire completed by the children themselves at age 11.ResultsPLEs were reported among 11% of the children. Multinomial logistic regression models with probability weights to adjust for potential selection bias due to attrition suggested that maternal fever, genitourinary infections and influenza-like illness were associated with a weak to moderate increased risk of subclinical psychosis-like symptoms in the offspring, whereas respiratory tract infections were not. No clear pattern was observed between the strengths of the associations and the timing of exposure, or the type of psychosis-like symptom.ConclusionsIn this study, maternal exposures to fevers and common infections in pregnancy were generally associated with a subtle excess risk of PLEs in the child. A more pronounced association was found for influenza-like illness under an a priori definition, leaving open the possibility that certain kinds of infections may constitute important risk factors. [ABSTRACT FROM PUBLISHER]

The purpose of this paper is to describe the development and initial accomplishments of a training program of young leaders in community mental health research as part of a Latin American initiative known as RedeAmericas. RedeAmericas was one of five regional 'Hubs' funded by the National Institute of Mental Health (NIMH) to improve community mental health care and build mental health research capacity in low- and middle-income countries. It included investigators in six Latin American cities - Santiago, Chile; Medellín, Colombia; Rio de Janeiro, Brazil; and Córdoba, Neuquén, and Buenos Aires in Argentina - working together with a team affiliated with the Global Mental Health program at Columbia University in New York City. One component of RedeAmericas was a capacity-building effort that included an Awardee program for early career researchers in the mental health field. We review the aims of this component, how it developed, and what was learned that would be useful for future capacity-building efforts, and also comment on future prospects for maintaining this type of effort. [ABSTRACT FROM AUTHOR]

BackgroundWhether the incidence of eating disorders in Western, industrialized countries has changed over time has been the subject of much debate. The purpose of this primary-care study was to examine changes in the incidence of eating disorders in The Netherlands during the 1980s, 1990s and 2000s.MethodA nationwide network of general practitioners (GPs), serving a representative sample (~1%) of the total Dutch population, recorded newly diagnosed patients with anorexia nervosa (AN) and bulimia nervosa (BN) in their practice during 1985–1989, 1995–1999, and 2005–2009. GPs are key players in the Dutch healthcare system, as their written referral is mandatory in order to get access to specialized (mental) healthcare, covered by health insurance. Health insurance is virtually universal in The Netherlands (99% of the population). A substantial number of GPs participated in all three study periods, during which the same case identification criteria were used and the same psychiatrist was responsible for making the final diagnoses. Incidence rates were calculated and for comparison between periods, incidence rate ratios.ResultsThe overall incidence rate of BN decreased significantly in the past three decades (from 8.6 per 100 000 person-years in 1985–1989 to 6.1 in 1995–1999, and 3.2 in 2005–2009). The overall incidence of AN remained fairly stable during three decades, i.e. 7.4 per 1 00 000 person-years in 1985–1989, 7.8 in 1995–1999, and 6.0 in 2005–2009.ConclusionsThe incidence rate of BN decreased significantly over the past three decades, while the overall incidence rate of AN remained stable. [ABSTRACT FROM PUBLISHER]

Background Lower and middle income countries (LMICs) are home to >80% of the global population, but mental health researchers and LMIC investigator led publications are concentrated in 10% of LMICs. Increasing research and research outputs, such as in the form of peer reviewed publications, require increased capacity building (CB) opportunities in LMICs. The National Institute of Mental Health (NIMH) initiative, Collaborative Hubs for International Research on Mental Health reaches across five regional 'hubs' established in LMICs, to provide training and support for emerging researchers through hub-specific CB activities. This paper describes the range of CB activities, the process of monitoring, and the early outcomes of CB activities conducted by the five research hubs. Methods The indicators used to describe the nature, the monitoring, and the early outcomes of CB activities were developed collectively by the members of an inter-hub CB workgroup representing all five hubs. These indicators included but were not limited to courses, publications, and grants. Results Results for all indicators demonstrate a wide range of feasible CB activities. The five hubs were successful in providing at least one and the majority several courses; 13 CB recipient-led articles were accepted for publication; and nine grant applications were successful. Conclusions The hubs were successful in providing CB recipients with a wide range of CB activities. The challenge remains to ensure ongoing CB of mental health researchers in LMICs, and in particular, to sustain the CB efforts of the five hubs after the termination of NIMH funding. [ABSTRACT FROM AUTHOR]

Background There remains a large disparity in the quantity, quality and impact ofmental health research carried out in sub-Saharan Africa, relative to both the burden and the amount of research carried out in other regions. We lack evidence on the capacity-building activities that are effective in achieving desired aims and appropriate methodologies for evaluating success. Methods AFFIRM was an NIMH-funded hub project including a capacity-building program with three components open to participants across six countries: (a) fellowships for an M.Phil. program; (b) funding for Ph.D. students con0ducting research nested within AFFIRM trials; (c) short courses in specialist research skills. We present findings on progression and outputs fromtheM.Phil. andPh.D. programs, self-perceivedimpactof short courses,qualitativedataonstudent experience, andreflections on experiences and lessons learnt from AFFIRMconsortium members. Results AFFIRMdelivered funded research training opportunities to 25 mental health professionals, 90 researchers and five Ph.D. students across 6 countries over a period of 5 years.Anumber of challengeswere identified and suggestions for improving the capacity-building activities explored. Conclusions Having protected time for research is a barrier to carrying out research activities for busy clinicians. Funders could support sustainability of capacity-building initiatives through funds for travel and study leave. Adoption of a trainthe-trainers model forspecialist skills training and strategies for improving the rigorof evaluationof capacity-building activities should be considered. [ABSTRACT FROM AUTHOR]

BackgroundThe risk for psychotic disorders is increased for many ethnic minority groups and may develop in early childhood. This study investigated whether the prevalence of psychotic experiences (PE) with high impact is higher among ethnic minority youth compared to majority youth and examined the significance of these PE.MethodA school-based study assessed a large community sample of 1545 ethnic minority and majority children in The Netherlands (mean age 12.98 ± 1.81 years). The Dutch (n = 702, 45.4%), Moroccan-Dutch (n = 400, 25.9%) and Turkish-Dutch (n = 170, 11.0%) ethnic groups could be studied separately. Self-report questionnaires on PE, impact and cultural context were administered.ResultsPrevalence of PE with high impact was 3.1% in Dutch, 9.5% in Moroccan-Dutch and 7.1% in Turkish-Dutch youth. Compared to Dutch youth, odds ratios were 3.0 [95% confidence interval (CI) 1.7–5.1] for Moroccan-Dutch youth and 2.2 (95% CI 1.1–4.6) for Turkish-Dutch youth. Differences were not explained by cultural or religious differences.ConclusionsThe increased risk for psychotic disorders in ethnic minorities may already be detectable in childhood, since PE with high impact were more common among ethnic minority youth compared to majority youth. The additional measurement of impact of PE appears to be a valid approach to identify those children at risk to develop psychotic or other more common psychiatric disorders. [ABSTRACT FROM PUBLISHER]

Background.The incidence of schizophrenia is commonly estimated by screening for psychosis among subjects presenting to psychiatric services. This approach (using a first-contact sampling frame) cannot account for cases that did not meet criteria for schizophrenia at first contact. We compared the usual approach directly with a register-based approach (using a longitudinal sampling frame) that also includes subjects initially diagnosed with other non-schizophrenic disorders.Method.We compared data from the Longitudinal Psychiatric Register (LPR) of The Hague over 1980–2009 with data previously collected in a first-contact study, and applied both methods to calculate the incidence of schizophrenia for subjects aged 20–54 years in the same catchment area and over the same period (October 2000 to September 2005). We reconstructed treatment pathways and diagnostic histories up to the end of 2009 and performed sensitivity analyses.Results.The LPR identified 843 first onsets of schizophrenia, corresponding to a treated incidence rate (IR) of 69 per 100 000 person-years [95% confidence interval (CI) 64–74]. The first-contact study identified 254 first onsets, corresponding to a treated IR of 21 per 100 000 person-years (95% CI 18–23). Two-thirds of the difference was accounted for by subjects treated for other disorders before the onset of psychosis, and by patients in older age groups.Conclusions.The incidence of schizophrenia was three times higher in a longitudinal register study than in a high-quality first-contact study conducted in the same population. Risk estimates based only on first-contact studies may have been affected by selection bias. [ABSTRACT FROM AUTHOR]

BackgroundAccumulating evidence suggests that fetal growth restriction may increase risk of later schizophrenia but this issue has not been addressed directly in previous studies. We examined whether the degree of fetal growth restriction was linearly related to risk of schizophrenia, and also whether maternal pre-eclampsia, associated with both placental dysfunction and poor fetal growth, was related to risk of schizophrenia.MethodA population-based cohort of single live births in the Medical Birth Registry of Norway (MBRN) between 1967 and 1982 was followed to adulthood (n = 873 612). The outcome was schizophrenia (n=2207) registered in the National Insurance Scheme (NIS). The degree of growth restriction was assessed by computing sex-specific z scores (standard deviation units) of ‘birth weight for gestational age’ and ‘birth length for gestational age’. Analyses were adjusted for potential confounders. Maternal pre-eclampsia was recorded in the Medical Birth Registry by midwives or obstetricians using strictly defined criteria.ResultsThe odds ratio (OR) for schizophrenia increased linearly with decreasing birth weight for gestational age z scores (p value for trend = 0.005). Compared with the reference group (z scores 0.01–1.00), the adjusted OR [95% confidence interval (CI)] for the lowest z-score category (< − 3.00) was 2.0 (95% CI 1.2–3.5). A similar pattern was observed for birth length for gestational age z scores. Forty-nine individuals with schizophrenia were identified among 15 622 births with pre-eclampsia. The adjusted OR for schizophrenia following maternal pre-eclampsia was 1.3 (95% CI 1.0–1.8).ConclusionsAssociations of schizophrenia risk with degree of fetal growth restriction and pre-eclampsia suggest future research into schizophrenia etiology focusing on mechanisms that influence fetal growth, including placental function. [ABSTRACT FROM PUBLISHER]

BackgroundThe goal of the current study was to investigate asthma and mental health among youth in the community, and to consider the role of asthma severity and persistence in this link.MethodData were drawn from the Raine Study, a population-based birth cohort study in Western Australia. Logistic regression models and generalized estimating equations were used to examine the relationship between asthma at age 5 years and the range of internalizing and externalizing mental health problems at ages 5–17 years. Analyses were stratified by asthma severity and persistence, and adjusted for a range of potential confounders.ResultsMore severe and persistent asthma at age 5 was associated with significantly increased odds of affective, anxiety, somatic, oppositional defiant and conduct problems at ages 5–17. Mild asthma and remitted asthma were not associated with heightened vulnerability to mental disorders.ConclusionsOur results suggest that youth with symptomatic asthma are more likely to suffer from a wide range of mental health problems, and that the likelihood of mental health problems appears to increase as a function of asthma severity. Youth with poorly controlled and/or more severe and persistent asthma may be considered a vulnerable group who might benefit from mental health screening in clinical, school and community settings. [ABSTRACT FROM PUBLISHER]

The reported prevalence of autism spectrum disorders (ASDs) has increased by 5- to 10-fold over the past 20 years. Whether ASDs are truly more frequent is controversial; nonetheless, the burden is profound in human and economic terms. Although autism is among the most heritable of mental disorders, its pathogenesis remains obscure. Environmental factors are proposed; however, none is implicated. Furthermore, there are no biomarkers to screen for ASD or risk of ASD. The Autism Birth Cohort (ABC) was initiated to analyze gene × environment × timing interactions and enable early diagnosis. It uses a large, unselected birth cohort in which cases are prospectively ascertained through population screening. Samples collected serially through pregnancy and childhood include parental blood, maternal urine, cord blood, milk teeth and rectal swabs. More than 107 000 children are continuously screened through questionnaires, referral, and a national registry. Cases are compared with a control group from the same cohort in a ‘nested case–control’ design. Early screening and diagnostic assessments and re-assessments are designed to provide a rich view of longitudinal trajectory. Genetic, proteomic, immunologic, metagenomic and microbiological tools will be used to exploit unique biological samples. The ABC is a paradigm for analyzing the role of genetic and environmental factors in complex disorders. [ABSTRACT FROM AUTHOR]

An assessment protocol for the longitudinal measurement of developmental psychopathology in a population-based study of children and adolescents is proposed. The protocol is designed for use in a large cohort of up to 100 000 individuals followed from early gestation to 21 years of age. Although the protocol was constrained by specified methodological parameters, the recommendations may apply to other psychiatric epidemiological research designs. The issues and challenges inherent with psychiatric assessments in longitudinal epidemiological studies of children and adolescents are discussed. [ABSTRACT FROM AUTHOR]