Sibling aggregation for psychiatric disorders in offspring at high and low risk for depression: 10-year follow-up

Correlations between caregiver psychiatric symptoms and offspring psychopathology in a low-resource setting

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The DSM5/RDoC debate on the future of mental health research: implication for studies on human stress and presentation of the signature bank

In 2008, the National Institute of Mental Health (NIMH) announced that in the next few decades, it will be essential to study the various biological, psychological and social "signatures" of mental disorders. Along with this new "signature" approach to mental health disorders, modifications of DSM were introduced. One major modification consisted of incorporating a dimensional approach to mental disorders, which involved analyzing, using a transnosological approach, various factors that are commonly observed across different types of mental disorders. Although this new methodology led to interesting discussions of the DSM5 working groups, it has not been incorporated in the last version of the DSM5. Consequently, the NIMH launched the "Research Domain Criteria" (RDoC) framework in order to provide new ways of classifying mental illnesses based on dimensions of observable behavioral and neurobiological measures. The NIMH emphasizes that it is important to consider the benefits of dimensional measures from the perspective of psychopathology and environmental influences, and it is also important to build these dimensions on neurobiological data. The goal of this paper is to present the perspectives of DSM5 and RDoC to the science of mental health disorders and the impact of this debate on the future of human stress research. The second goal is to present the "Signature Bank" developed by the Institut Universitaire en Santé Mentale de Montréal (IUSMM) that has been developed in line with a dimensional and transnosological approach to mental illness.

Implications of high-risk family studies for prevention of depression

The high-risk family study is a powerful design that facilitates identification of early forms of expression of depression and premorbid vulnerability, risk, and protective factors that are important for defining prevention targets and program foci. This paper (1) highlights the strengths of high-risk studies for informing early intervention efforts; (2) summarizes findings of familial aggregation from controlled high-risk studies of depression; and (3) briefly reviews evidence for potential mediators (i.e., early forms of expression, vulnerability factors) that explain familial risk and for moderators (i.e., interactive risk and protective factors) that enhance or minimize familial risk. New data from the Yale High-Risk Study of Comorbidity of Substance Use and Affective Disorders are presented to exemplify strategies for identifying specific familial pathways to depression among offspring of parents with substance and anxiety disorders. Likewise, parental depression is associated with a range of emotional and behavioral problems, including anxiety and conduct disorder, in their offspring. These nonspecific effects, together with emerging findings on mechanisms of risk, support early intervention efforts that target a range of youth at risk for depression through multipronged approaches that attend to the individual characteristics of the child and parent, clinical comorbidity, and the broader family and social context.

Twin studies in pediatric depression

Pediatric depression is an important clinical problem that is known to be familial. Twin studies have been used not only to examine the genetic etiology of depression but also to investigate developmental changes and gender effects, the relationship of depression with anxiety, and increasingly, the interplay of genetic liability with environmental risk factors. There is evidence that pediatric depression symptom scores and clinical depression are genetically influenced, but results from different twin studies have varied. These studies also have demonstrated the important contribution of environmental risk factors. Some of the differences in findings may be caused partly by clinical heterogeneity, developmental differences in etiology (stronger genetic influences for depression symptom scores in adolescence than in childhood), and measurement issues, such as who rates the symptoms.

Future of genetics of mood disorders research

This report summarizes the deliberations of a panel with representation from diverse disciplines of relevance to the genetics of mood disorders. The major charge to the panel was to develop a strategic plan to employ the tools of genetics to advance the understanding, treatment, and outcomes for mood disorders. A comprehensive review of the evidence for the role of genetic factors in the etiology of mood disorders was conducted, and the chief impediments for progress in gene identification were identified. The National Institute of Mental Health (NIMH) portfolios in the Genetics Research Branch and the Division of Mental Disorders, Behavioral Sciences, AIDS, and all genetics training activities were reviewed. Despite some promising leads, there are still no confirmed linkage findings for mood disorders. Impediments to gene finding include the lack of phenotypic validity, variation in ascertainment sources and methodology across studies, and genetic complexity. With respect to linkage, the committee recommended that a large-scale, integrated effort be undertaken to examine existing data from linkage and association studies of bipolar disorders using identical phenotypes and statistical methods across studies to determine whether the suggestive linkage findings at some loci can be confirmed. Confirmation would justify more intensive approaches to gene finding. The committee recommended that the NIMH support continued efforts to identify the most heritable subtypes and endophenotypes of major depression using the tools of genetic epidemiology, neuroscience, and behavioral science. The field of genetic epidemiology was identified as an important future direction because population-based, epidemiologic studies of families and unrelated affected individuals assume increasing importance for common chronic diseases. To prepare for shifts to more complex genetic models, the committee recommended that the NIMH develop new interdisciplinary training strategies to prepare for the next generation of genetics research.

Pediatric bipolar mood disorder

The diagnosis of bipolar mood disorder (BP) in preadolescents (pediatric mania) has generated considerable controversy in terms of its estimated prevalence and validity as a diagnostic category. The relative paucity of systematic studies and the current diagnostic confusion related to the disorder are often attributed to the apparent discontinuities in the childhood versus adult presentation of the illness, namely, irritability as the predominant "mood" of mania and a continuous course of symptoms. The goal of this article is to review the current literature and identify sources of confusion relating to pediatric mania by considering results to date within a larger context that include findings from studies on (1) BP illness in adults, (2) mood disorders across the lifespan, (3) the role of development in symptom expression, and (4) patterns of heritability in psychiatric disorders. Whereas much remains to be investigated in the validation of the diagnosis for children, integrating results across studies may provide a framework for understanding the differences in the presentation of severe mood disorders in children and adults.

The genetic aetiology of childhood depression: a review

BACKGROUND

We review the evidence for the familiality of major depressive disorder (MDD) and the genetic aetiology of depressive symptoms in children and adolescents.

METHODS

Databases and reference lists were searched for family, twin and adoption studies of childhood MDD and childhood depressive symptoms. Data from independent family studies that fulfilled specified inclusion criteria were pooled and odds ratios were calculated for top-down and bottom-up family studies.

RESULTS

Estimates of familial risk differ by control group and by study design (odds ratio range 1.70, 3.98). Twin studies show that depressive symptoms in young people are heritable although rater and measurement issues are important. Adoption studies show little evidence for a genetic influence on depressive symptoms.

CONCLUSIONS

MDD in young people is familial although control group and study design affect the magnitude of the familial risk. Estimates of heritability from twin and adoption studies vary widely and few firm conclusions can be made regarding the genetic aetiology of depressive symptoms in childhood. Areas that require future work include the examination of rater effects, measurement issues, the effects of age and comorbidity and reasons for the discrepancy between twin and adoption findings.

Bringing up bashful baby. Developmental pathways to social phobia

Shyness is a risk factor for, or an early manifestation of, more enduring problems with social anxiety. But the majority of shy children do not develop social phobia, and factors that further increase risk are poorly understood, underscoring the complexity of this relationship. Studies uniformly show that social phobia (particularly the generalized subtype) runs in families, and twin studies suggest that a moderate component of this familial tendency is genetic in origin. Understanding the genetic etiology of other neuropsychiatric disorders characterized by abnormal social interest, social communication (e.g., autism), or both may prove informative for social phobia. The contribution of unique experiences to the development of social phobia is clear from genetic studies, but studies to date have failed to elucidate what kinds of experiences might be involved. Given patient reports that socially traumatic conditioning experiences have often occurred, detailed evaluation of these kinds of experiences in monozygotic twins discordant for social phobia would be a particularly informative research strategy. Nongenetic familial factors probably have more limited effects on the development of social phobia, although the impact of parental modeling of, and acquiescence to, childhood social fears deserves to be further investigated. These factors may be particularly salient for the expression of social phobia in children whose genes render them susceptible. If so, it should be possible to design early interventions to prevent the progression from phobia proneness (e.g., designated on the basis of family history) to phobic disorder.

Adolescent depression: a review

OBJECTIVE

To review the characteristic clinical, illness course and risk factors to adolescent depression.

METHOD

A literature review is provided with interpretive comments.

RESULTS

The clinical feature profile is likely to reflect the rarity of melancholic depression, while the non-melancholic "irritable hostile" pattern appears distinctly increased. A "reactive depressive disorder" is rare in those who get to psychiatric assessment, while comorbidity (e.g. anxiety and personality disorders, illicit drug use) is the rule. Aetiological determinants and the prognosis generally more relate to comorbid factors than to depression per se. Predisposing and precipitating psychological and social determinants are considered, while the efficacies of varying antidepressant strategies remain unclear apart from those with an "anxious" or "irritable" depression where selective serotonin re-uptake inhibitor medication has shown utility and where cognitive-behavioural therapy may be relevant.

CONCLUSIONS

For the majority who develop adolescent depression, its expression and outcome appear more a reflection of the propagating determinants, most commonly anxiety and personality style. The clinician should determine a treatment plan that not only addresses the depression but which identifies and addresses the contributing features.

Genetic and environmental influences on the temporal association between earlier anxiety and later depression in girls

BACKGROUND

The purpose of the present study was to investigate the role of genetic and environmental factors in the association between depressive symptoms and symptoms of overanxious disorder, simple phobias, and separation anxiety in 8-13-year-old and 14-17-year-old girls.

METHODS

Multivariate genetic models were fitted to child-reported longitudinal symptom data gathered from clinical interview on 415 MZ [corrected] and 194 DZ [corrected] female twin pairs from the Virginia Twin Study of Adolescent Behavioral Development (VTSABD) [corrected].

RESULTS

Model-fitting results suggest there are distinct etiological [corrected] patterns underlying the association between depression and the different anxiety syndromes during the course of development: 1) specific genetic influences on depression after age 14 reflect liability to symptoms of earlier overanxious disorder (OAD) and simple phobias; 2) aspects of the shared environment that influence symptoms of depression before age 14 contribute to symptoms of separation anxiety and simple phobias later in adolescence [corrected]; 3) the shared environmental influence on [corrected] depression in 14+ girls also affects liability to symptoms of concurrent OAD and persistent separation anxiety.

CONCLUSIONS

These results suggest that depression before and after age 14 may be etiologically distinct syndromes. Earlier symptoms of OAD and (to a lesser extent phobic symptoms) [corrected] reflect the same genetic risk, and separation anxiety symptoms both before and after age 14 reflect the same environmental risk that influence liability to depressive symptoms expressed in middle to late adolescence.

Comorbidity of depression in children and adolescents: models and evidence from a prospective high-risk family study

Despite abundant research demonstrating the magnitude of comorbidity and its importance in understanding childhood psychopathology, there has been limited empirical research designed to examine the nature and causes of comorbidity among youth. This article reviews the current literature on the magnitude and mechanisms of depressive comorbidity and presents data to exemplify the application of high-risk and longitudinal study designs to investigate patterns and explanations for comorbidity. A prospective family study of offspring at high and low risk for the development of anxiety was used to examine the specificity of familial comorbidity of depression and anxiety and the longitudinal stability of "pure" and comorbid disorders over an 8-year period. Findings suggest some specificity of familial expression, as well as longitudinal specificity, of depression and anxiety. The onset of depression follows the onset of most anxiety subtypes, suggesting the sequential nature of depressive comorbidity. Evaluation of mechanisms for comorbidity is important for the identification of homogeneous syndrome categories that will inform research designed to gain understanding of the pathogenesis of mood or anxiety disorders.