bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Political Feasibility of Privatizing Old‐Age Insurance
Authors: Hirte Georg 
Published: September 2003

AbstractThough a transition to a fully funded pension system is favoured by many economists, it is not even considered by politicians in Germany. This paper examines the hypothesis that this is in accordance with the preferences of the population. By performing a dynamic CGE analysis referenda on pension policies are simulated. They show that a fully privatizing scheme is not politically feasible in Germany, however long the pre‐announcement period, if the alternatives are the current policy or a partially privatizing policy. This explains why a fully privatizing policy is not an issue in the political debate in Germany. In order to examine what are the reasons for this outcome, the German Bismarckian System is compared to a Beveridge‐System which is similar to the British pension system. Actually, in the latter case, a transition to a fully funded system is what the majority opts for in a dynamically consistent equilibrium. This is evidence that the future of the pension system depends on its history.
A twin study of anxiety‐related behaviours in pre‐school children
Authors: Eley Thalia C. , Bolton Derek , O'Connor Thomas G. , Perrin Sean , Smith Patrick , Plomin Robert 
Published: September 2003

Background: From middle childhood onwards, substantial evidence points to phenotypic differentiation between anxiety diagnostic categories such as generalised anxiety, separation anxiety, specific phobia, and obsessive‐compulsive disorders. However, little is known about the genetics of these categories and especially about the phenotypic and genetic structure of related behaviours in pre‐school children.Methods: We examined the phenotypic differentiation and genetics of mother‐reported anxiety‐related behaviours in 4,564 four‐year‐old twin pairs, from a population‐based sample.Results: Confirmatory factor analyses provided support for five correlated factors: General Distress, Separation Anxiety, Fears, Obsessive‐Compulsive Behaviours, and Shyness/Inhibition. Genetic influences were found on all five factors, but the pattern of influences differed considerably across them, with particularly high heritability estimates for Obsessive‐Compulsive Behaviours and Shyness/Inhibition, and substantial shared environmental influence on Separation Anxiety. Multivariate genetic analyses revealed moderate genetic correlations between the five factors. Genetic overlap was particularly pronounced between General Distress and the other anxiety‐related behaviours, accounting for about half of their covariance. Genetic variance on Obsessive‐Compulsive Behaviours was the least correlated with the other scales. The shared environmental influences correlated highly across the factors, accounting for the greatest proportion of covariation between Separation Anxiety, Fears and Obsessive‐Compulsive Behaviours. The non‐shared environment influences were largely variable specific.Conclusions: These data provide evidence for phenotypic and genetic overlap as well as differentiation between aspects of anxiety‐related behaviours in young children. We conclude that research with young children will benefit from more specific assessments of anxiety‐related behaviours in addition to less differentiated assessments of ‘internalising’ symptoms.
Sibling‐based association analyses of the serotonin transporter polymorphism and internalizing behavior problems in children
Authors: Young Susan E. , Smolen Andrew , Stallings Michael C. , Corley Robin P. , Hewitt John K. 
Published: September 2003

Background:Childhood internalizing problems are often precursors in the development of more serious psychiatric syndromes including anxiety and depressive disorders. Twin studies of the etiology of these disorders suggest that the genetic risk factors underlying anxiety and depression are highly correlated. However, the specific genetic mechanisms responsible for this risk have not yet been identified.Methods:We examined the association between childhood internalizing problems and a functional polymorphism in the serotonin transporter gene (5‐HTTLPR) in 711 children participating in a longitudinal twin study of behavioral and emotional development. Internalizing problems were measured at ages 4, 7, 9, 10, 11 and 12 years using the Child Behavior Checklist (CBCL) parent report form. We applied a sibling‐based methodology for estimating allelic association with quantitative traits, while controlling for population stratification.Results:No associations were found for CBCL Internalizing problems at any age, including the subscales for Somatic Complaints, Withdrawn and Anxiety/Depression.Conclusions:Thus, although our results did not support the hypothesis that the 5‐HTTLPR contributes to a dimensional expression of internalizing behavior problems, this does not rule out the possibility that it is an interesting polymorphism to pursue in the search for genetic risk factors related to major depressive and/or anxiety disorders.
Depressive symptoms in children and adolescents: changing aetiological influences with development
Authors: Scourfield Jane , Rice Frances , Thapar Anita , Harold Gordon T. , Martin Neilson , McGuffin Peter 
Published: September 2003

Background: Evidence suggests that depressive symptoms become increasingly heritable as children grow into adolescence. However, the literature is not entirely consistent in this respect and existing longitudinal twin studies have examined changes within adolescence only.Method: Parent and self‐report questionnaire data were used to examine the genetic and environmental influences on depressive symptoms in a UK sample of 670 twin pairs aged 5–17. Age effects were examined cross‐sectionally and longitudinally using data collected over a 3‐year period.Results: Cross‐sectional analyses showed that shared environmental effects had significant influence in younger children but not in adolescence, when depression scores were significantly more heritable. The results of these cross‐sectional analyses were supported when two waves of parent‐report data collected over three years were analysed. Significant new genetic influences emerged in adolescence but no new shared environmental influences. Some sex differences were found, with girls showing greater genetic influence than boys, but only from parent‐report data.Conclusions: These findings support and extend earlier work which has shown increasing genetic influence on depressive symptoms as children grow into adolescence.
Negative life events as an account of age‐related differences in the genetic aetiology of depression in childhood and adolescence
Authors: Rice Frances , Harold Gordon T. , Thapar Anita 
Published: September 2003

Background: Many twin studies have reported that the genetic aetiology of depression differs according to age, with genetic influences being more important for adolescents than younger children. We sought to examine whether this age‐related increase in the relative importance of genetic factors is due to an increase in gene–environment correlation specifically involving negative life events.Method: Questionnaires were sent to the families of a population‐based sample of twins aged between 8 and 17 years. Parents of all the twins and adolescents aged 11 and over were asked to complete the Mood and Feelings Questionnaire (Costello & Angold, 1988) and a modified version of the Life Events Checklist (Johnson & McCutcheon, 1980). Responses were obtained from 1468 families and data were analysed using genetic model fitting. Bivariate analysis of 1) negative life events and 2) behaviour‐dependent life events and depression symptoms was undertaken separately for children (aged 8 to 10 years) and adolescents (aged 11 to 17 years). Differences in genetic and environmental parameters across age groups were tested.Results: Adolescence was associated with a greater number of behaviour‐dependent life events. Genetic covariation of negative life events and depression was greater for adolescents than for children.Conclusions: Bivariate model fitting was consistent with the greater heritability of depression seen in adolescence being due to an increase in gene–environment correlation involving negative life events. However, the effects of genes associated specifically with maturation in adolescence, the possibility of ‘person’ effects and the role of other environmental factors also need to be considered.
Genetic epidemiology of self‐reported lifetime DSM‐IV major depressive disorder in a population‐based twin sample of female adolescents
Authors: Glowinski Anne L. , Madden Pamela A.F. , Bucholz Kathleen K. , Lynskey Michael T. , Heath Andrew C. 
Published: September 2003

Background: In adults, about 40% of the variance in risk of Major Depressive Disorder (MDD) is due to genetic factors, but little data exist on the heritability of youth MDD. The goal of this study was the genetic analysis of MDD in an epidemiologically and genetically representative sample of adolescent female twins.Methods: A sample of 3416 female adolescent twins systematically ascertained from birth records was assessed using a structured telephone interview that included a comprehensive DSM‐IV‐based section for the diagnostic assessment of MDD. Mean subject age at time of assessment was 15.5 and participation rate exceeded 85%. Genetic modeling was conducted taking into consideration the problem of censoring, i.e., that younger adolescents were not through their period of risk for adolescent onset of MDD.Results: Lifetime self‐reported MDD prevalence ranged from 1% under age 12 to 17.4% at age 19 and older. The genetic variance in risk of MDD was 40.4% (95% confidence interval (CI): 23.9–55.1), with the remaining variance explained by non‐shared environmental effects 59.6% (95%CI: 44.9–76.1). Shared environmental effects were not significant. A significant recall bias was observed with older respondents on average reporting later onsets for their first episode of MDD.Conclusions: The genetic and environmental contributions to risk of MDD in this representative sample of female adolescent twins are remarkably analogous to findings from adult samples. These results are congruent with a conceptualization of adolescent MDD and adult MDD as having very similar etiologic determinants.
Adolescent twins discordant for major depressive disorder: shared familial liability to externalizing and other internalizing disorders
Authors: Burcusa Stephanie L. , Iacono William G. , McGue Matt 
Published: September 2003

Background: In adolescents, as in adults, there is often comorbidity between major depressive disorder (MDD) and many other disorders. In this study, the discordant twin method was used to investigate whether this comorbidity in adolescents may be due to a shared familial liability between MDD and other internalizing disorders, and between MDD and externalizing disorders.Methods: We examined prevalence rates of anxiety disorders, substance use disorders, and childhood externalizing disorders in 624 seventeen‐year‐old same‐sex monozygotic and dizygotic twin pairs. Overall prevalence of MDD in this sample was 12.9%. Twenty‐seven twin pairs were concordant for MDD, 107 were discordant for MDD, and 490 were concordant for no MDD.Results: Prevalence rates for disorders other than MDD were elevated in the depressed twins relative to the control twins from pairs concordant for no MDD. Prevalence rates were also elevated in the nondepressed co‐twins of depressed twins. Twin concordance for disorders other than MDD was higher in twin pairs where at least one twin was depressed than in pairs where neither twin was depressed.Conclusions: These results support a shared familial liability between MDD and other internalizing disorders and between MDD and externalizing disorders in adolescents.
Resolving multiple epigenetic pathways to adolescent depression
Authors: Eaves Lindon , Silberg Judy , Erkanli Alaattin 
Published: September 2003

Background: Genotype × environment interaction (G × E) arises when genes influence sensitivity to the environment. G × E is easily recognized in experimental organisms that permit randomization of genotypes over fixed environmental treatments. Genotype–environment correlation (rGE) arises when genetic effects create or evoke exposure to environmental differences. Simultaneous analysis of G × E and such ‘active’ or ‘evocative’ rGE in humans is intractable with linear structural models widely used in behavioral genetics because environments are random effects often correlated with genotype. The causes of the environmental variation, therefore, need to be modeled at the same time as the primary outcome.Methods: A Markov Chain Monte Carlo approach is used to resolve three distinct pathways involving genes and life events affecting the development of post‐pubertal depression in female twins and its relationship to pre‐pubertal anxiety: 1) the main of genes and environment; 2) the interaction of genes and environment (G × E); and 3) genotype–environment correlation (rGE).Results: A model including G × E and rGE in addition to the main effects of genes and environment yields significant estimates of the parameters reflecting G × E and rGE. Omission of either G × E or rGE leads to overestimation of the effects of the measured environment and the unique random environment within families.Conclusions: 1) Genetic differences in anxiety create later genetic differences in depression; 2) genes that affect early anxiety increase sensitivity (G × E) to adverse life events; 3) genes that increase risk to early anxiety increase exposure to depressogenic environmental influences (rGE). Additional genetic effects, specific to depression, further increase sensitivity to adversity. Failure to take into account the effects of G × E and rGE will lead to misunderstanding how genes and environment affect complex behavior.
Developmental differences in neuronal engagement during implicit encoding of emotional faces: an event‐related fMRI study
Authors: Nelson Eric E. , McClure Erin B. , Monk Christopher S. , Zarahn Eric , Leibenluft Ellen , Pine Daniel S. , Ernst Monique 
Published: September 2003

Background: Prior studies document strong interactions between emotional and mnemonic processes. These interactions have been shown to vary across development and psychopathology, particularly mood and anxiety disorders.Methods: The present study used functional neuroimaging to assess the degree to which adolescents and adults differ in patterns of neuronal engagement during implicit encoding of affective stimuli. Subjects underwent rapid event‐related fMRI while viewing faces with angry, fearful, happy, and neutral expressions. A surprise post‐scan memory test was administered.Results: Consistent with previous findings, both adolescents and adults displayed engagement of left ventrolateral prefrontal cortex when viewing subsequently recognized stimuli. Age differences emerged in patterns of neuronal activation associated with subsequent recognition of specific face‐emotion types. Relative to adults, adolescents displayed more activity in the anterior cingulate when viewing subsequently remembered angry faces, and more activity in the right temporal pole when viewing subsequently remembered fear faces. Conversely, adults displayed more activity in the subgenual anterior cingulate when viewing subsequently remembered happy faces and more activity in the right posterior hippocampus when viewing subsequently remembered neutral faces. These age‐related differences emerged in the absence of differences in behavioral performance.Conclusions: These findings document developmental differences in the degree to which engagement of affective circuitry contributes to memory formation.
Maternal antenatal anxiety and behavioural/emotional problems in children: a test of a programming hypothesis
Authors: O'Connor Thomas G. , Heron Jonathan , Golding Jean , Glover Vivette ,   the AL SPAC Study Team
Published: September 2003

Background: Previous animal investigations link antenatal stress with a range of persistent behavioural abnormalities in the offspring. The current study examined if the effect was also found in humans through middle childhood.Methods: The current study is based on the Avon Longitudinal Study of Parents and Children (ALSPAC), a prospective, community‐based study that has followed a cohort of women from pregnancy. Self‐report measures of maternal anxiety and depression were assessed at repeated intervals in pregnancy and the postnatal period. Children's behavioural/emotional problems were assessed by parent report at age 47 and 81 months. Information on obstetric and psychosocial factors was obtained at several points in pregnancy and the postnatal period.Results: Children whose mothers experienced high levels of anxiety in late pregnancy exhibited higher rates of behavioural/emotional problems at 81 months of age after controlling for obstetric risks, psychosocial disadvantage, and postnatal anxiety and depression (for girls, OR = 1.91, 95%CI = 1.26–2.89; for boys, OR = 2.16, 95%CI = 1.41–3.30). Furthermore, the effect at 81 months was comparable to what was previously obtained at 47 months, suggesting the kind of persistent effect proposed in the animal literature.Conclusions: There is evidence that antenatal stress/anxiety has a programming effect on the fetus which lasts at least until middle childhood.
Mother–child joint activity and behaviour problems of pre‐school children
Authors: Galboda‐Liyanage Kumari Chandani , Prince Martin James , Scott Stephen 
Published: September 2003

Background: Behaviour problems are common among pre‐school children, and a substantial proportion persist, causing significant burden to the family, schools and health services. Relatively little research has addressed the effects of positive parenting on behaviour disorder in pre‐school children, particularly in larger population‐based studies.Method: A cross‐sectional postal survey of a representative, population‐based sample of 800 mothers of 3½‐year‐old children living in an outer London Borough was carried out to assess the association between mother–child joint activity and behaviour problems of pre‐school children. The response rate was 70%.Results: Lower levels of mother–child joint activity remained independently associated with behaviour problems of pre‐school children both on a binary and a continuous scale after adjusting for a wide range of household, maternal and child circumstances. The association between low levels of mother–child joint activities and behaviour problems of the children was stronger in the presence of social problems in the family.Conclusion: Possible causal pathways and directions for future research and intervention are discussed.
Low‐ and high‐level controlled processing in executive motor control tasks in 5–6‐year‐old children at risk of ADHD
Authors: Kalff Ariane C. , De Sonneville Leo M.J. , Hurks Petra P.M. , Hendriksen Jos G.M. , Kroes Marielle , Feron Frans J.M. , Steyaert Jean , Van Zeben Thea M.C.B. , Vles Johan S.H. , Jolles Jelle 
Published: September 2003

Background: The scant research on the characteristics of Attention‐Deficit/Hyperactivity Disorder (ADHD) in kindergarten years curtails progress on early assessment of ADHD.Method: By screening a general population sample of 1317 five‐ to six‐year‐old children, four groups of children were selected. The performance of 30 children later diagnosed with ADHD was compared with 74 children later diagnosed with ‘borderline ADHD’ (children exhibiting all ADHD symptoms but without disruptions on two situations), 113 children later diagnosed with other psychopathology, and 126 healthy controls on computerised motor control tasks involving low‐ and high‐level controlled processing. In addition, motor control was compared with movement speed.Results: The children at risk of ADHD were in general less accurate and more variable in their movements than the children with other psychopathology and healthy controls. Under conditions of high‐level controlled processing, the children at risk of ADHD were disproportionately more inaccurate and had a more unstable performance with their preferred hand than the other children. In addition, linear effects were found, with the children at risk of ADHD having the worst performance, followed by the children with ‘borderline ADHD’, and then both groups of control children. No significant group differences were found in movement speed.Conclusions: The main findings are interpreted as evidence for a specific deficit in high‐level controlled processing in young children at risk of ADHD, now found in a motor task, rather than a response task. Furthermore, the results support the notion that ADHD represents a dimensional trait. In addition, problems in movement control (the need to allocate attentional capacity) rather than problems in movement speed distinguish children at risk of ADHD from other children. The findings are interpreted as evidence that higher‐order executive processes, such as self‐control and self‐regulation, are already affected early in the development of ADHD.
Suicidal ideations and attempts in juvenile delinquents
Authors: Ruchkin Vladislav V. , Schwab‐Stone Mary , Koposov Roman A. , Vermeiren Robert , King Robert A. 
Published: September 2003

Background: Suicidality among adolescents is a common focus of clinical attention. In spite of links to disruptive behaviors and other types of psychopathology, it is not clear whether other factors commonly associated with suicide, such as personality and parenting, predict suicidality over and above psychopathology. The purpose of the present study was to assess suicidal ideations and attempts and their relationship to psychopathology, violence exposure, personality traits and parental rearing in Russian male juvenile delinquents with conduct disorder (CD).Method: Suicidality and psychopathology were assessed using a semi‐structured psychiatric interview in 271 incarcerated male juvenile delinquents diagnosed with CD. Violence exposure, personality characteristics and perceived parental rearing were assessed via self‐reports.Results: Thirty‐four percent of those diagnosed with CD (92 subjects) reported a lifetime history of either suicidal thoughts or attempts. Suicidal ideators and attempters did not differ significantly on any variable of interest, but both reported significantly higher rates of psychopathology and violence exposure than the non‐suicidal group, as well as higher levels of harm avoidance, lower self‐directedness, and higher rates of perceived negative parental rearing. Finally, even when controlling for the relationship with psychopathology, personality and perceived parental rearing factors showed significant associations with suicidality.Conclusions: Juvenile delinquents with CD have high rates of suicidal ideations and attempts, related to a wide spectrum of psychopathology and specific personality traits. These findings suggest that a combination of intrinsic and extrinsic factors create vulnerability to stressors, which under the influence of situational factors (e.g., repeated traumatization) may lead to suicidal thoughts and acts. Factors potentially contributing to vulnerability for suicidality should be identified when planning prevention and rehabilitation efforts for troubled youth.