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Objective: Depression often co-occurs with poor health-related quality of life (HRQL). Twin studies report genetic and individual-level environmental underpinnings in the aetiology of both depression and HRQL, but there is limited twin research exploring this association further. There is also little evidence on sex differences and non-Western populations are underrepresented. In this paper we explored the phenotypic and aetiological relationship between depressive symptoms and HRQL and possible sex differences in a low-middle-income Sri Lankan population., Method: Data for 3,948 participants came from the Colombo Twin and Singleton Follow-up Study (CoTaSS-2). Using self-report measures of depressive symptoms and HRQL, we conducted univariate and bivariate sex-limitation twin analyses., Results: Depressive symptoms showed moderate genetic (33%) and strong nonshared environmental influences (67%). Nonshared environment accounted for the majority of variance in all the subscales of HRQL (ranging from 68 to 93%), alongside small genetic influences (ranging from 0 to 23%) and shared environmental influences (ranging from 0 to 28%). Genetic influences were significant for emotional wellbeing (23%). Shared environmental influences were significant for four out of the eight HRQL variables (ranging from 22-28%), and they were more prominent in females than males. Depressive symptoms were significantly associated with lower HRQL scores. These correlations were mostly explained by overlapping nonshared environmental effects. For traits related to emotional functioning, we also detected substantial overlapping genetic influences with depressive symptoms., Conclusions: Our study confirmed previous findings of a negative association between depressive symptoms and HRQL. However, some of the aetiological factors of HRQL differed from Western studies, particularly regarding the effects of shared environment. Our findings highlight the importance of cross-cultural research in understanding associations between psychological wellbeing and HRQL., Competing Interests: The authors have declared that no competing interests exist.

Purpose: Life events have been associated with a variety of mental health conditions including depression. There is a scarcity of research in South Asia exploring the aetiology of independent and dependent life events and their relationship with depression symptoms. This study aimed, in a Sri Lankan population, to identify the socio-demographic correlates and genetic and environmental influences on independent and dependent life events and their relationship with depression., Methods: Questionnaire data came from the Colombo Twin and Singleton Follow-up Study, CoTaSS-2 (N = 3969), a population study of Sri Lankan twins and singletons. Lifetime-ever independent and dependent life events were measured using a questionnaire and depressive symptoms using the Revised Beck's Depression Inventory. Structural Equation Model-fitting analyses explored the genetic and environmental influences on life events and depression., Results: Living in a rural environment and financial hardship were associated with greater reporting of independent and dependent life events. Sex differences were evident in the aetiology of life events and depression symptoms. Independent and dependent life events, but not depression symptoms, were heritable in males. Independent life events and depression symptoms, but not dependent life events, were heritable in females. Non-shared environmental influences explained phenotypic associations between independent life events and depression symptoms in both males and females. Genetic and non-shared environmental influences explained the phenotypic associations between dependent life events and depression symptoms in males. Only non-shared environment explained the covariation between dependent life events and depression symptoms in females., Conclusions: Socio-demographic correlates of independent and dependent life events were similar to those reported in Western populations. Life events were associated with increased depression symptoms. Contrary to research in Western populations, we found that non-shared environmental, rather than genetic, influences explained much of the covariation between life events and depression symptoms. This suggests that whilst independent LEs may be heritable, the relationship is unlikely to be confounded by genetic influences and has significant implications for possible interventions for depression.

The current study sought to examine the direction of influences on longitudinal associations between anxiety sensitivity, anxiety and depression. The continuity of genetic and environmental influences on these traits over adolescence was also investigated. Self reports of anxiety sensitivity, anxiety and depression were collected from approximately 1,300 twin and sibling pairs, on two occasions (mean ages 15 and 17). The direction and etiology of the associations between these traits were examined using longitudinal genetic cross-lagged models. All traits were stable over time and this stability accounted for the largest proportion of variance at time 2. There was, however, also evidence of reciprocal associations between variables over time. Genetic effects were fairly stable across time, although new genetic influences were evident at the second time point. Environmental effects tended to be more time specific. This study adds to our understanding of the direction of effects between anxiety sensitivity, anxiety and depression in adolescence, and the risks underlying their associations.

Study Objectives: To establish the direction and etiology of longitudinal associations between sleep problems and depression symptoms in children., Design: Data on twins aged 8 and 10 years were obtained. At assessments, parents completed the Child Sleep Habits Questionnaire, and twins completed the Children's Depression Inventory., Setting: Participants were mainly interviewed at the Institute of Psychiatry, London., Patients or Participants: Three hundred twin pairs initially enrolled in the study., Interventions: N/A., Measurements and Results: A genetically informative cross-lagged model examined links between sleep and depression. Sleep problems at age 8 predicted depression at age 10 (partial regression coefficient [95% confidence intervals] = 0.10 [0.01-0.18]). The converse was not found. Stability of sleep problems across time was mainly due to genes (46% of the genetic influence on sleep at 10 was due to the same genetic influence on sleep aged 8). Stability of depression was mainly due to non-shared environmental influences (19% of the nonshared environmental influence on depression at 10 was due to the same nonshared environmental influence on depression at age 8). The cross-lagged association between sleep problems at 8 and depression at 10 years was largely due to genes, although this finding was nonsignificant., Conclusions: This study adds to our understanding of the temporal precedence of sleep problems and depression and the risks underlying their associations. There are implications regarding the value of specifying genes linked to sleep problems and potential opportunities for informing early intervention strategies in high-risk groups at key points in the progression to developing more serious problems.

Rejection sensitivity and the associated fear of negative social evaluation (FNSE) trait are characteristics of hypocortisolemic syndromes such as atypical depression. However, a meta-analysis showed that acute FNSE evokes strong cortisol responses in humans. This is consistent with suggestions that hypocortisolism reflects a protective adaptation to a history of high cortisol responses. This leads us to hypothesize that measures of trait FNSE relate to hypocortisolism. Moreover, because FNSE relates positively to depressed mood state, but negatively to cortisol, we expect that the positive relationship between depressed mood state and cortisol will show up most clearly when controlling for the confounding effect of FNSE on this relationship. In the present study we measured salivary cortisol awakening response and psychological variables in 194 community women aged 18-30 years. The results confirmed our hypotheses. We propose that dispositional FNSE is associated with a history of frequent high cortisol responses, leading to long-term protective inhibition of further cortisol and energy mobilization. The present results have special relevance for mental health problems that have high prevalence among young women.

Less is known about depression in children than in adults. This study integrates fields by combining cognitive and interpersonal research investigating childhood depression symptoms through the use of a genetic framework. Three research questions are addressed. First, what are the associations among interpersonal cognitions, anxiety, and depression? Second, what are the relative magnitudes of genetic and environmental influences on interpersonal cognitions? Third, to what extent do genetic and environmental influences explain associations between interpersonal cognitions and depression? Three hundred pairs of 8-year-old twins reported on symptoms of depression and anxiety by completing the Children's Depression Inventory and the Screen for Childhood Anxiety-Related Emotional Disorders. The authors examined interpersonal cognitions with the Children's Expectation of Social Behaviors and the Perceptions of Peers and Self Questionnaires. Interpersonal cognitions were more strongly correlated with depression (mean r = .35) than with anxiety (mean r = .13). Genetic influence on interpersonal cognitions was small (M = 3%), and associations between interpersonal cognitions and depression were mainly explained by environmental influences. These latter findings may result from interpersonal cognitions in young children, reflecting life experiences as opposed to trait-like cognitive biases., ((c) 2007 APA)

Objectives: Associations between sleep and internalizing problems are complex and poorly understood. To better understand these covarying difficulties, genetic and environmental influences were estimated by using a twin design., Methods: Three hundred 8-year-old twin pairs reported on their anxiety and depression by completing the Screen for Childhood Anxiety Related Emotional Disorders and the Children's Depression Inventory. Parents reported on their children's sleep problems by completing the Child Sleep Habits Questionnaire., Results: Children reported by their parents to have different types of sleep problems self-reported more depression symptoms than those without. The correlation between total sleep-problem score and depression was moderate. That between sleep problems and anxiety was smaller and was not examined further. The association between sleep problems and depression was mainly explained by genes, and there was substantial overlap between the genes influencing sleep problems and those influencing depression. There was smaller influence from environmental factors making family members alike, and environmental factors making family members different decreased the association between sleep problems and depression., Conclusions: A range of sleep difficulties are associated with depression in school-aged children, and the overall association between the 2 difficulties may be largely influenced by genes.

A strong association between functional disability and depressive symptoms in older people has frequently been reported. Some studies attribute this association to the disabling effects of depression, others to the depressogenic effects of physical health-related disability. The authors examined the reciprocal effects between depressive symptoms and functional disability and their temporal character in a community-based cohort of 753 older people with physical limitations who were assessed at yearly intervals. They compared structural equation models that differed in terms of direction and speed of effects between patient-reported disability in instrumental and basic activities of daily living (IADL/ADLs) and depressive symptoms. The association between disability and depression could be separated into three components: (a) a strong contemporaneous effect of change in disability on depressive symptoms, (b) a weaker 1-year lagged effect of change in depressive symptoms on disability (probably indirect through physical health), and (c) a weak correlation between the trait (or stable) components of depression and disability. IADL/ADL disability and depressive symptoms are thus mutually reinforcing over time. Compensatory forces like effective treatment and age-related adaptation may protect elders against this potential downward trend. To improve quality of life in elderly adults, treatment should target disability when it is new and depression when it is persistent.

Abstract: Background: There is a substantial overlap between genes affecting anxiety and depression. Both anxiety and depression are associated with cognitive biases such as anxiety sensitivity and attributional style. Little, however, is known about the relationship between these variables and whether these too are genetically correlated. Methods: Self-reports of anxiety sensitivity, anxiety symptoms, attributional style and depression symptoms were obtained for over 1300 adolescent twin and sibling pairs at two time points. The magnitude of genetic and environmental influences on the measures was examined. Results: Strongest associations were found between anxiety sensitivity and anxiety ratings at both measurement times (r =.70, .72) and between anxiety and depression (r =.62 at both time points). Correlations between the cognitive biases were modest at time 1 (r =−.12) and slightly larger at time 2 (r =−.31). All measures showed moderate genetic influence. Generally genetic correlations reflected phenotypic correlations. Thus the highest genetic correlations were between anxiety sensitivity and anxiety ratings (.86, .87) and between anxiety and depression ratings (.77, .71). Interestingly, depression ratings also showed a high genetic correlation with anxiety sensitivity (.70, .76). Genetic correlations between the cognitive bias measures were moderate (−.31, −.46). Limitations: The sample consists primarily of twins, there are limitations associated with the twin design. Conclusions: Cognitive biases associated with depression and anxiety are not as genetically correlated as anxiety and depression ratings themselves. Further research into the cognitive processes related to anxiety and depression will facilitate understanding of the relationship between bias and symptoms. [Copyright &y& Elsevier]