Biopsychosocial changes in the human stress response, with specific reference to stress measurement and certain moderating variables.

Abstract

This empirical double-blind multi-centre empirical study assessed the sources of stress, stress-related symptoms, role of psychosocial moderating variables and the role of micronutrients (specifically the effect of intervention with micronutrient supplementation) on stress levels and symptoms in South Africans. The sample consisted of 300 volunteer, English-speaking South Africans from two centres (KwaZulu-Natal and Gauteng) who had predetermined stress levels. The participants were evenly divided between the two centres (N=150 each). The Experimental Group (Active group) who comprised 151 participants received a multivitamin and mineral combination, while the Control Group (Placebo) group received a placebo. The research dealt with perceived stressors, coping resources and outcomes in the general population (both at baseline and after intervention). Outcome was assessed using standardized self-report instruments which examined stress levels and symptoms, perception of stress levels, anxiety, psychological general well-being and neurocognitive functions (verbal and visual memory). Univariate and multivariate correlational analyses were performed to investigate correlations and the predictive value of risk and rescue factors for the outcome variables.

The findings indicate that there were no significant differences in the number of stressors between the two groups at baseline, although they differed in respect of two particular stressors (A>P regarding concern over children's future; P>A regarding life decisions). An interaction of stressors and moderating variables (life orientation and perceived coping incapacity) have an important role in predicting stress and stress outcome, and outcomes themselves may function as stressors. The bidirectional, circular interactive effects of stressors, moderators and outcomes are important in the stress and coping process. The study failed to find any effect of stress on the neurocognitive functions assessed. No significant treatment effect for the micronutrient was found, but a number of trends in respect of efficacy were suggested by the findings. The findings also suggested particular patterns of interactions in this regard for predicting pre-post differences (delta). Strengths and limitations of the study are highlighted and implications for intervention in respect of a stress management programme are also discussed.