Aetiology of fatigue in Sri Lanka and its overlap with depression

Is the Pandemic Wearing Us Out? A Cross-Sectional Study of the Prevalence of Fatigue in Adult Twins without Previous SARS-CoV-2 Infection

During the pandemic, mental health was not only impaired in people after a SARS-CoV-2 infection, but also in people without previous infection. This is the first study on twins without prior SARS-CoV-2 infection to estimate the influence of genetic components and shared as well as individual environments on pandemic-associated fatigue. The study sample included 55 monozygotic and 45 dizygotic twin pairs. A total of 34.5% reported an increase in fatigue since the pandemic. A significant correlation was shown between the responses within monozygotic (χ2[1] = 11.14, p = 0.001) and dizygotic pairs (χ2[1] = 18.72, p < 0.001). In all pandemic-associated fatigue dimensions, individual environment (ranging from e2 = 0.64 to e2 = 0.84) and heritability (ranging from h2 = 0.32 to h2 = 1.04) seem to have the highest impact. The number of comorbidities significantly correlated with physical fatigue (Spearman’s ρ = 0.232, p < 0.001) and psychological impairment due to pandemic measures with the total fatigue score (Spearman’s ρ = 0.243, p < 0.001). However, calculated ANCOVAs with these significant correlations as covariates showed no significant influence on the mean values of the respective fatigue dimensions. Susceptibility to pandemic-associated fatigue may be genetically and environmentally determined, while intensity is also influenced by individual components. The prevalence of fatigue is high even in individuals without prior SARS-CoV-2 infection. Future mental health prevention and intervention programs should be implemented to alleviate the impact of the pandemic on the global population.

The aetiological relationship between depressive symptoms and health-related quality of life: A population-based twin study in Sri Lanka

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.

Familiality and Heritability of Fatigue in an Australian Twin Sample

Familial factors have previously been implicated in the etiology of fatigue, of which a significant proportion is likely attributable to genetic influences. However, family studies have primarily focused on chronic fatigue syndrome, while univariate twin studies have investigated broader fatigue phenotypes. The results for similar fatigue phenotypes vary between studies, particularly with regard to sex-specific contributions to the heritability of the traits. Therefore, the current study aims to investigate the familiality and sex-specific effects of fatigue experienced over the past few weeks in an older Australian population of 660 monozygotic (MZ) twin pairs, 190 MZ singleton twins, 593 dizygotic (DZ) twin pairs, and 365 DZ singleton twins. Higher risks for fatigue were observed in MZ compared to DZ co-twins of probands with fatigue. Univariate heritability analyses indicated fatigue has a significant genetic component, with a heritability (h2) estimate of 40%. Sex-specific effects did not significantly contribute to the heritability of fatigue, with similar estimates for males (h2= 41%, 95% CI [18, 62]) and females (h2= 40%, 95% CI [27, 52]). These results indicate that fatigue experienced over the past few weeks has a familial contribution, with additive genetic factors playing an important role in its etiology.

Shared Genetic Factors in the Co-Occurrence of Depression and Fatigue

Depression and fatigue have previously been suggested to share an underlying genetic contribution. The present study aims to investigate and characterize the familiality and genetic relationship between depression and fatigue. The familiality of depression and fatigue was assessed by calculating relative risks, measured by the prevalence ratio, within 643 monozygotic (MZ) and 577 dizygotic (DZ) twin pairs. Bivariate twin modeling was utilized to assess the magnitude of shared heritability between depression and fatigue. Finally, the relationship between depression and fatigue was investigated using the co-twin control method, to determine whether the association is explained by causal or non-causal models. We observed an increased risk of fatigue in co-twins of probands with depression and increased risk of depression in co-twins of probands with fatigue. Higher risks were observed in MZ compared to DZ twin pairs, and bivariate heritability analyses indicated significant genetic components for depression and fatigue, with heritability estimates of 48% and 41%, respectively. Importantly, a significant additive genetic correlation of 0.71 [95% CI = 0.51-0.92) and bivariate heritability of 21% [95% CI = 10-35%] was observed between depression and fatigue. Furthermore, results from the co-twin control method indicate a non-causal genetic relationship that likely explains the association between depression and fatigue. Notably, the contribution of shared genetic factors remained significant, independent of the overlapping symptoms, indicating that the relationship between co-occurring depression and fatigue is primarily due to shared genetic factors rather than overlapping symptomatology.

[Comorbidity of depression and nonaffective - schizophrenia spectrum disorders: the clinical-epidemiological study EDIP]

AIM

To explore the association between depression and heterogenic nonaffective symptom complexes in the study EDIP (Epidemiology of Depression and nonaffective Psychiatric disorders).

MATERIAL AND METHODS

The study consisted of two stages. The first stage (91 patients) aimed to resolve organizational and methodological issues, the second stage was performed in the epidemiological sample of 705 patients.

RESULTS AND CONCLUSION

The heterogeneity (inequivalence and bidirectionality) of associations between depression and heteronomous nonaffective disorders have been identified. The associations are distinguished in three types: 1) affinity (agonism); 2) repulsion (antagonism); 3) lack of selective interaction (inertness) between depression and nonaffective disorders. The results obtained are discussed in a context of two conceptually polar psychopathological models of comorbidity between depression and nonaffective disorders: 1) based on a nosological dichotomy «affective disease - schizophrenia» and 2) denying the abovementioned dichotomy. The first model places depression among disorders of a mild psychiatric register. The second model supposes the integration of depression with syndromes typical for schizophrenia in a common "affect-symptoms" space and considers the increase of depression frequency proportionally to duration and severity of schizophrenia. Our own results have shown that depression is observed not only among disorders of mild psychiatric registers, but also in schizophrenia, though with a significantly lower frequency (as a nonobligatory compound of a syndrome). Thus, depression influence in comorbid delusional, schizophrenic and other severe nonaffective disorders is greatly diminished.

Mental health status of Sri Lanka Navy personnel three years after end of combat operations: a follow up study

The main aim of this study was to assess the mental health status of the Navy Special Forces and regular forces three and a half years after the end of combat operations in mid 2009, and compare it with the findings in 2009. This cross sectional study was carried out in the Sri Lanka Navy (SLN), three and a half years after the end of combat operations. Representative samples of SLN Special Forces and regular forces deployed in combat areas were selected using simple random sampling. Only personnel who had served continuously in combat areas during the one year period prior to the end of combat operations were included in the study. The sample consisted of 220 Special Forces and 275 regular forces personnel. Compared to regular forces a significantly higher number of Special Forces personnel had experienced potentially traumatic events. Compared to the period immediately after end of combat operations, in the Special Forces, prevalence of psychological distress and fatigue showed a marginal increase while hazardous drinking and multiple physical symptoms showed a marginal decrease. In the regular forces, the prevalence of psychological distress, fatigue and multiple somatic symptoms declined and prevalence of hazardous drinking increased from 16.5% to 25.7%. During the same period prevalence of smoking doubled in both Special Forces and regular forces. Prevalence of PTSD reduced from 1.9% in Special Forces to 0.9% and in the regular forces from 2.07% to 1.1%. Three and a half years after the end of combat operations mental health problems have declined among SLN regular forces while there was no significant change among Special Forces. Hazardous drinking among regular forces and smoking among both Special Forces and regular forces have increased.

Association of somatoform disorders with anxiety and depression in women in low and middle income countries: a systematic review

BACKGROUND

Across cultures, women are more likely than men to report somatoform disorders (SD), depression and anxiety. The aim of this article is to describe the co-morbidity of SD with depression/anxiety and to investigate the possible mechanisms of this relationship in women in low and middle income countries (LMIC).

METHODS

We reviewed two databases: MEDLINE and PsycINFO from 1994 to 2012 for studies which assessed the association between any SD and depression/ anxiety in women from LMIC. Our focus was on community and primary healthcare based studies. Both quantitative and qualitative studies were included.

RESULTS

A total of 21 studies covering eight LMICs were included in our analysis. Our findings suggest a strong association between SD and depression/anxiety (with odds ratios ranging from 2.5-3.5), though we also observed that the majority of women with SD did not have depression/anxiety. The likely mechanisms for this association are multidimensional, and may include shared aetiologies, that both conditions are in fact variants of the same primary mental disorder, and that one disorder is a risk factor for the other. Anthropological research offers a number of frameworks through which we can view these mechanisms.

CONCLUSION

The current evidence indicates that service providers at the primary care level should be sensitized to consider SD in women as variants of CMD (Common Mental Disorders) and address both groups of disorders concurrently. Further research should explicitly seek to unpack the mechanisms of the relationship between SD and CMD.

The Sri Lankan Twin Registry: 2012 update

The Sri Lankan Twin Registry (SLTR), established in 1997, is a unique resource for twin and genetic research in a low- and middle-income country (LMIC). It comprises of a volunteer cohort of 14,120 twins (7,060 pairs) and 119 sets of triplets, and a population-based cohort of 19,040 (9,520 pairs) twins and 89 sets of triplets. Several studies have been conducted using this registry, including the Colombo Twin and Singleton Study (CoTaSS 1; 4,387 twins, 2,311 singletons), which have explored the prevalence and heritability of a range of psychiatric disorders as well as gene-environmental interplay. Currently, a follow-up study (CoTaSS 2) of the same cohort is underway, looking at the prevalence and interrelationship of key cardiovascular and metabolic risk markers (e.g., metabolic syndrome). A significant feature of CoTaSS 2 is the establishment of a biobank. Current SLTR work is extending beyond mental health and the interface between mental and physical health to new horizons, extending collaborations with the wider global twin research community. Ethics and governance have been given special emphasis in the initiative. Capacity building and public engagement are two crucial components. Establishment of a state-of-the-art genetic laboratory was a major accomplishment. SLTR is a classic showcase of successful North-South partnership in building a progressive research infrastructure in a LMIC.

The development and validation of the Peradeniya Depression Scale (PDS)--a culturally relevant tool for screening of depression in Sri Lanka

BACKGROUND

Cultural factors may influence the manner in which a given population interprets and conceptualizes their experience of depression. The aim of this study is to validate the Peradeniya Depression Scale (PDS), a locally created, culturally relevant tool for detection of depression in Sri Lanka.

METHOD

Fifty currently depressed patients (diagnosed via the Structured Clinical Interview for DSM Disorders) and 50 (non-depressed) controls were administered the PDS.

RESULTS

At a score of 10/25 the PDS showed a sensitivity 88.5% and specificity of 85.0% with regards to the detection of depression. Culturally appropriate statements, which referred to international criteria of depression and somatic symptoms, showed significantly higher odds of being positive in depressed patients compared to controls.

LIMITATIONS

The PDS was validated among an outpatient population presenting to a psychiatry clinic in a government hospital in Peradeniya, Sri Lanka. While this is fairly representative of patients presenting to government hospital clinics in this country, further multi-centre studies in different areas of the country maybe useful.

CONCLUSION

The PDS is the first screening tool for depression developed and validated in Sri Lanka, written in Sinhalese, taking into account cultural expressions and idioms of the illness. It shows satisfactory sensitivity and specificity as a screening tool for depression. The findings also suggest that it maybe worthwhile for Asian countries to consider adopting scales which are based on internationally accepted diagnostic criteria for depression, but which incorporate expressions that are more appropriate to their own culture and language.

Genetic and environmental contributions to the overlap between psychological, fatigue and somatic symptoms: a twin study in Sri Lanka

BACKGROUND

Somatic symptoms often co-occur with psychological symptoms but this overlap is poorly understood. Some aspects of this overlap differ in the South Asian context, but it is not clear whether this is a reporting effect or an underlying difference in experienced illness.

METHODS

Home interviews were administered to 4,024 twins randomly selected from a population-based twin register in the Colombo district of Sri Lanka (the CoTASS study). These included assessments of psychological, somatic and fatigue symptoms. The data were analyzed using factor analytic and quantitative genetic approaches.

RESULTS

Confirmatory factor analysis showed that the symptoms from the three scales represented three separate dimensions, rather than all tapping into a single dimension. However, familial correlations among the data were most consistent with a common pathway model. This implies that a portion of the underlying vulnerability is common across psychological, fatigue and somatic symptoms. There were sex differences in the etiology of this model, with shared environmental and genetic influences playing different roles in men and women.

CONCLUSIONS

There is a complex etiological relationship between psychological, fatigue and somatic symptoms. This is similar in Sri Lanka to Western countries, but there may be a greater influence from the family environment, suggesting that care needs to be taken when generalizing research findings between countries. People who complain of certain fatigue or somatic symptoms may well also have psychological symptoms, or may have genetic or environmental vulnerabilities to such problems.

A disabling combination: fatigue and depression

Fatigue and common psychiatric symptoms - depression in particular - have consistently been found to be strongly associated. All have a negative impact on functional status, but evidence suggests that functional impairment is especially marked when they co-occur. Therefore, it is pertinent to understand the relationship between fatigue and depression.

Environmental exposures and their genetic or environmental contribution to depression and fatigue: a twin study in Sri Lanka

BACKGROUND

There is very little genetically informative research identifying true environmental risks for psychiatric conditions. These may be best explored in regions with diverse environmental exposures. The current study aimed to explore similarities and differences in such risks contributing to depression and fatigue.

METHODS

Home interviews assessed depression (lifetime-ever), fatigue and environmental exposures in 4,024 randomly selected twins from a population-based register in the Colombo district of Sri Lanka.

RESULTS

Early school leaving and standard of living showed environmentally-mediated effects on depression, in men. In women, life events were associated with depression partly through genetic pathways (however, the temporal order is consistent with life events being an outcome of depression, as well as the other way around). For fatigue, there were environmentally mediated effects (through early school leaving and life events) and strong suggestions of family-environmental influences.

CONCLUSIONS

Compared to previous studies from higher-income countries, novel environmentally-mediated risk factors for depression and fatigue were identified in Sri Lanka. But as seen elsewhere, the association between life events and depression was partially genetically mediated in women. These results have implications for understanding environmental mechanisms around the world.