Clarifying the causes of consistent and inconsistent findings in genetics

Interaction of social support and depressive symptoms on antiretroviral therapy adherence among people living with HIV in South Africa

Background

Depression consistently emerges as a significant predictor of poor antiretroviral therapy (ART) adherence among adult people living with human immunodeficiency virus (PLHIV). However, a gap exists regarding how social support and depressive symptoms can interact to influence ART adherence among adult PLHIV in South Africa (SA).

Aim

To investigate the interaction between social support and depressive symptoms on ART adherence among adult PLHIV.

Setting

A tertiary hospital in Durban, KwaZulu-Natal province of SA.

Methods

Utilising a quantitative cross-sectional research design along with time location sampling technique (TLS); the study recruited 201 adult patients enrolled in an ART programme.

Results

The results indicated that depressive symptoms were significantly associated with ART adherence with and without the interaction (B = -0.105; odds ratios [OR] 0.901; 95% confidence intervals [CI] = 0.827, 0.981; p = 0.016), while social support was not significantly associated with ART adherence (B = 0.007; OR 1.007; 95%CI = 0.989, 1.025; p = 0.475). However, a statistically significant interaction was found between social support and depressive symptoms (B = -0.006; OR 0.994; 95%CI = 0.989, 1.000; p = 0.037) on ART adherence.

Conclusion

Based on the results, depressive symptoms significantly influenced ART adherence. However, social support did not buffer the adverse effects of clinical depression associated with poor ART adherence.

Contribution

This study provides an evidence-based approach to address gaps in the mental health and social well-being of PLHIV in the context of ART adherence.

Analysis of genetic diversity in patients with major psychiatric disorders versus healthy controls: A molecular-genetic study of 1698 subjects genotyped for 100 candidate genes (549 SNPs)

BACKGROUND

This study analyzed the extent to which irregularities in genetic diversity separate psychiatric patients from healthy controls.

METHODS

Genetic diversity was quantified through multidimensional "gene vectors" assembled from 4 to 8 polymorphic SNPs located within each of 100 candidate genes. The number of different genotypic patterns observed per gene was called the gene's "diversity index".

RESULTS

The diversity indices were found to be only weakly correlated with their constituent number of SNPs (20.5 % explained variance), thus suggesting that genetic diversity is an intrinsic gene property that has evolved over the course of evolution. Significant deviations from "normal" diversity values were found for (1) major depression; (2) Alzheimer's disease; and (3) schizoaffective disorders. Almost one third of the genes were correlated with each other, with correlations ranging from 0.0303 to 0.7245. The central finding of this study was the discovery of "singular genes" characterized by distinctive genotypic patterns that appeared exclusively in patients but not in healthy controls. Neural Nets yielded nonlinear classifiers that correctly identified up to 90 % of patients. Overlaps between diagnostic subgroups on the genotype level suggested that (1) diagnoses-crossing vulnerabilities are likely involved in the pathogenesis of major psychiatric disorders; (2) clinically defined diagnoses may not constitute etiological entities.

CONCLUSION

Detailed analyses of the variation of genotypic patterns in genes along with the correlation between genes lead to nonlinear classifiers that enable very robust separation between psychiatric patients and healthy controls on the genotype level.