Heritability of depressive symptoms: a case study using a multilevel approach.

TL;DR: This study uses kinship information from a large national family dataset, the NLSY79, whose respondents are approximately representative of United States adolescents in 1979, and presents the first biometrical analysis of the relationships between SES and health that uses an overall SES measure.

TL;DR: This research presents a new perspective on the dual role of emotion and social reinforcement in the development of psychopathology and its role in decision-making in the context of youth.

TL;DR: Prepubertal-onset anxiety disorder is a risk factor for the later development of clinically significant recurrent MDD across several generations of families at high risk for depression and Parental impaired functioning increases the risk for disruptive disorders.

TL;DR: In this article, five criteria are proposed to evaluate the appropriateness of the "X is a gene for Y" concept: strength of association, specificity of relationship, noncontingency of effect, causal proximity of X to Y, and the degree to which X is the appropriate level of explanation for Y.

Abstract: In a longitudinal study of Dutch adolescent and young adult twins, their parents and their siblings, questionnaire data were collected on depression, anxiety and correlated personality traits, such as neuroticism. Data were collected by mailed surveys in 1991, 1993, 1995 and 1997. A total of 13,717 individuals from 3344 families were included in the study. To localise quantitative trait loci (QTLs) involved in anxiety and depression, the survey data were used to select the most informative families for a genome-wide search. For each individual a genetic factor score was computed, based on a genetic multivariate analysis of anxiety, depression, neuroticism and somatic anxiety. A family was selected if at least two siblings (or DZ twins) had extreme factor scores. Both discordant (high-low) and concordant (high-high and low-low) pairs were included in the selected sample. Once an extreme sibling pair was selected, all family members (parents and additional siblings of the selected pair) who had at least once returned a questionnaire booklet were asked to provide a DNA sample. In total, 2724 individuals from 563 families (1007 parents and 1717 offspring) were approached and 1975 individuals from 479 families (643 patients and 1332 offspring) complied by returning a buccal swab for DNA isolation. All offspring from selected families were asked to participate in a psychiatric interview and in a 24-hour ambulatory assessment of cardiovascular parameters and cortisol. The interview consisted of the WHO-Composite International Diagnostic Interview and was administered to 1253 offspring. In this paper we describe the genetic-epidemiological analyses of the survey data on anxiety, somatic anxiety, neuroticism and depression. We detail how these data were used to select families for the QTL study and discuss strategies that may help elucidate the molecular pathways leading from genes to anxious depression.

TL;DR: The complexity of psychiatric phenotypes is demonstrated by the evidence accumulating for an overlap in genetic susceptibility across the traditional classification systems that divide disorders into schizophrenia and mood disorders, and evidence suggestive of gene-environment interactions.