Heritability of individual depressive symptoms (original) (raw)
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Heritability of depressive symptoms: a case study using a multilevel approach
International Journal of Methods in Psychiatric Research, 2009
We present a case study using a multilevel modeling approach to determine whether depressive symptoms are affected by genetic factors. Existing studies examining this question have focused on twins. The present study built on the literature by conducting a preliminary study of the heritability of depressive symptoms within extended families. At the same time, this study assessed the need for adjustment of a heritability measure in a family study using a multigenerational sample. The sample consisted of 230 community-dwelling extended families that included 431 adult offspring, comprising full siblings, half siblings and cousins that participated in the University of Southern California Longitudinal Study of Generations. All participants fi lled out the Center for Epidemiologic Studies Depression (CES-D) scale. The multilevel analysis allowed us to model the natural hierarchy of the extended family. Results indicate that the proportion of the phenotypic variance for CES-D that occurs due to genetic differences is not signifi cantly larger than zero among these participants [h 2 = 8.6%, 95% confi dence interval (CI) = 0-57%, p = 0.71]. Our fi ndings suggest that future studies examining depressive symptoms in this sample can focus on non-genetic explanatory factors without the necessity to control for genetic variation. However, our study may be limited by measurement of prevalent depressive symptoms, which may not generalize to lifetime depressive symptoms.
Familiality of Symptom Dimensions in Depression
Archives of General Psychiatry, 2004
Background: Depression is a clinically heterogeneous disorder thought to result from multiple genes interacting with environmental and developmental components. A dimensional rather than a categorical approach to depressive phenotype definition may be more useful for identification of susceptibility genes. Objectives: To perform an exploratory factor analysis on a range of depressive and anxiety symptoms in a large, well-defined sample of depressed siblings, as well as a confirmatory factor analysis in a separate large group of unrelated depressed subjects, and to analyze correlations of identified symptom dimensions between depressed siblings. Design: Subjects (N = 1034), including 475 sibling pairs, with a history of at least 2 depressive episodes were recruited from the Depression Network Study, a largescale multicenter collection of families affected by recurrent unipolar depression. Subjects were interviewed using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) and diagnosed according to the DSM-IV and the International Classification of Diseases, 10th Revision, using a computerized scoring program (CATEGO5). Factor analysis was carried out on 26 depression symptom items, including 4 anxiety screening items. Confirmatory factor analysis was performed on an independent sample of 485 depressed individuals. Results: Four interpretable factors were identified: (1) mood symptoms and psychomotor retardation; (2) anxiety; (3) psychomotor agitation, guilt, and suicidality; and (4) appetite gain and hypersomnia. For each symptom group, a quantitative scale was constructed, and correlations between siblings were calculated. There was a moderate degree of sibling homotypia for some depressive symptoms, and factors 1, 2, and 3 showed significant positive familial correlation (0.145 [P=.001], 0.335 [PϽ.001], and 0.362 [PϽ.001], respectively). Conclusions: This is the first study of large, welldefined samples of depressed subjects in whom symptom dimensions have been derived and then confirmed using independent material. The significant correlations between siblings for 3 of the dimensions suggest substantial familial, perhaps genetic, etiologies.
The heritability of depressive symptoms: multiple informants and multiple measures
Journal of Child Psychology and Psychiatry, 2002
Background: Earlier research suggests large rater differences in heritability estimates of children's depressive symptoms in the context of significant age and sex-limitation effects. Methods: With data from an ongoing, population-based twin-family study, we estimated genetic and environmental influences on children's depression with models allowing for sex-specific effects. Our assessments of twins included self-reports and ratings made by their classmate peers, their parents and their teachers, allowing estimates of genetic and environmental effects with data from different informants. Modelfitting used maximum likelihood estimation of log-transformed data from a sample of 1,366 11-and 12year-old twin pairs. Results: Estimates of additive genetic effects were significant for both boys and girls across all four informants, and, standardized to reflect the percentage of phenotypic variance accounted for, those estimates ranged from .28 to .71. Significant effects from common environmental sources were found in ratings of teachers and parents, where, typically, one individual rated both co-twins, but neither in peer nominations nor self-ratings. The correlation of teacher and parent ratings was modest, and bivariate model-fitting found no correlation in either genetic or shared environmental effects between teacher and parental ratings. At this young age, sex-limitation effects were found only in teacher ratings, where genetic effects were greater in girls than in boys. Conclusions: Results underscore the utility of using multiple informants to measure children's behavior and provide a foundation for follow-up of these twins in later adolescence.
1990
Abstract To determine the etiology of self-reported depressive symptoms and their co-occurrence in the general population, multivariate genetic models were fitted to the responses of 771 female twin pairs (463 MZ, 308 DZ) to a 20-item epidemiological depression inventory (CES-D scale). A model which contained one common genetic factor, one shared environmental factor, and four unique environmental factors provided a useful account of symptom covariation.
2016
BackgroundBoth genetic and environmental contributions to risk of depression have been identified, but estimates of their effects are limited. Commonalities between major depressive disorder (MDD) and self-declared depression (SDD) are also unclear. Dissecting the genetic and environmental contributions to these traits and their correlation would inform the design and interpretation of genetic studies.MethodsUsing data from a large Scottish family-based cohort (GS:SFHS, N=21,387), we estimated the genetic and environmental contributions to MDD and SDD. Genetic effects associated with common genome-wide genetic variants (SNP heritability) and additional pedigree-associated genetic variation and Non-genetic effects associated with common environments were estimated using linear mixed modeling (LMM).FindingsBoth MDD and SDD had significant contributions from effects of common genetic variants, the additional genetic effect of the pedigree and the common environmental effect shared by c...
Journal of Affective Disorders, 2018
Background: Previous research has shown substantial heritability for depressive symptoms, yet, there are few genetically-informed studies which focused on developmental changes. The current study sought to model prototypical developmental trajectories of depressive symptoms from adolescence to adulthood and to elucidate genetic and environmental contributions to these changes. Methods: The Add Health data set, a nationally representative sample of adolescents, was used. For the genetically-informed analyses, a subsample of N = 531 same-sex monozygotic and dizygotic male and female twin pairs was selected. Longitudinal development was modeled separately for two waves in early adolescence and for four waves from middle adolescence to young adulthood using a latent growth model (LGM). Both models were extended to twin models to estimate the effects of heritability and the environment. Results: The rates of depressive symptoms peaked in mid-adolescence and then sharply declined as individuals moved from adolescence to young adulthood, with leveling off in the twenties. The effects of the shared environment were substantial among early adolescents, but negligible for middle-to-late adolescents. An opposite pattern was found for heritability. The largest proportion of developmental changes was driven by nonshared environmental effects. Limitations: The study only used same-sex twins as there exist mixed findings regarding the possibility of qualitative or quantitative genetic effects. Conclusions: The salience of unique experiences and to a lesser extent, heritable factors in affecting developmental changes in depressive symptoms, underscore the need for targeting such environments that place individuals with genetic predisposition at double the risk for the development of depression.
American Journal of Psychiatry, 1994
Objective: Self-reported symptoms of depression are commonly used in mental health research to assess current psychiatric state, yet wide variation in these symptoms among mdividuals has been found in both clinical and epidemiologic populations. The authors sought to understand, from a genetic-epidemiologic perspective, the sources of individual differences in depressive symptoms. Method: Self-reported symptoms of depression were assessed in two samples of twins and their spouses, parents, siblings, and offspring: one ...
Social Psychiatry and Psychiatric Epidemiology, 2009
Introduction Although associations between family history and depression have been shown in clinical patients, it is unknown if they also apply to subjects living in the community. The present study considers the relationship between family loading and depression phenotype characteristics in a large community-based sample. Method In a Dutch representative population sample of 7,076 individuals, lifetime diagnosis of depression was classified according to severity, course and age of onset. A family loading score of depression (FLSD) was computed by taking the proportion of the first-degree relatives for whom a history of depression was reported. Results There was a strong association between FLSD and lifetime diagnosis of MDD. Severity, recurrence and early onset of depression were the specific phenotypic characteristics associated with familiality. The effects of FLSD and gender were independent. Conclusion Associations between family history and risk for depression in the community confirm those reported from clinical-based studies using direct interviewing of relatives. A stronger degree of familiality is associated with specific phenotypic characteristics of depression.