Genetic and environmental contributions to depression in Sri Lanka

Abstract

BackgroundSusceptibility to depression results from genetic and non-familially shared environmental influences in high-income, Western countries. Environments may play a different role for populations in different contexts.AimsTo examine heritability of depression in the first large, population-based twin study in a low-income country.MethodLifetime depression and a broader measure of depression susceptibility (D-probe) were assessed in 3908 adult twins in Sri Lanka (the CoTASS study).ResultsThere were gender differences for the broad definition (D-probe), with a higher genetic contribution in females (61%) than males (4%). Results were similar for depression, but the prevalence was too low to estimate heritability for males.ConclusionsGenetic influences on depression in women appear to be at least as strong in this Sri Lankan sample as in higher-income countries. Conclusions are less clear for men but suggest a larger role for environments rather than genes. The nature as well as the magnitude of environmental influences may also differ across populations.

The Sri Lankan Twin Registry: 2012 Update

“…Overall, a very similar pattern of heritability has been shown in the current sample compared with results from twin studies in western countries for depression, fatigue, and tobacco use (Ball et al, 2009(Ball et al, , 2010cZavos et al, 2012). However, some differences were noted.…”

Aetiology of fatigue in Sri Lanka and its overlap with depression

“…Finally, we ran a bivariate model to decompose the covariation between abnormal fatigue and D-probe (see Table 5 for parameter estimates). As a result of previously identified gender differences in D-probe, 28 we did not attempt to equate the model across A, additive genetics; C, environmental influences shared across twins; E, non-shared environments; AIC, Akaike's information criterion. a.…”

The association between emotional eating and depressive symptoms: a population-based twin study in Sri Lanka

“…Studying and comparing common disorders in low- to middle-income countries of non-Caucasian ancestry is crucial to test if findings derived from Western populations are truly generalisable. A study of depression in a large Sri Lankan sample of twins from the Colombo Twin and Singleton Follow-up Study (COTASS-2) [18] found a pervasive effect of the environment on individual differences in depression in men and stronger genetic effects in women, suggesting substantial differences in the aetiology of depressive symptoms in this population [19]. This study highlighted the importance of cross-cultural comparisons; because the environmental exposures associated with EOE and depression are likely to be specific to the cultural, economic and cultural context of the specific samples studied.…”