PREVALENCE AND SEVERITY OF DEPRESSION AND ANXIETY AMONG RESIDENTS OF EAST KAZAKHSTAN REGION DEPENDING ON RADIATION EXPOSURE DUE TO THE ACTIVITY OF THE SEMIPALATINSK NUCLEAR TEST SITE
Background: studying the influence of environmental factors on mental health of the population is a widespread approach among modern researchers, which allows us to characterize the state of mental health both at individual and population levels. Assessment of mental distress is a necessary measure for the development of primary and secondary prevention programs on mental disorders. Despite the closure of the Semipalatinsk Nuclear Test Site (SNTS) in 1989, many social, demographic and economic issues remained unresolved. There is an aggravation of psychological tension among residents of the territories adjacent to the Site due to the spread of information by mass media unfairly reflecting the real radio-ecological situation in the region, as well as the consequences of radiation impact on public health. Aim: to study the prevalence and severity of depressive disorders and anxiety among the residents of Abay and Borodulikha districts, who were affected by long-term tests due to the activity of the SNTS, in comparison with inhabitants of ecologically safe Kurchum district. Materials and methods. The study had cross-sectional design. To achieve the study aim, we formed the study groups from the population of the East Kazakhstan region, in accordance with their radiation route. The sample size for the Abay district of comprised 222 people, while the sample size for Borodulikha district composed 233 people, and 245 people were recruited in Kurchum district (control group). PHQ-9 and GAD-7 scales were used to assess the presence and severity of depressive disorder and anxiety, respectively. The statistical processing of the study results was carried out using the SPSS statistical package (Statistical Package for the Social Sciences) version 20.0 for Windows (GMU Semey). Pearson’s chi-square was used to compare two independent groups of nominal variables. Differences between groups were considered to be significant if they had a 5% significance level (p <0.05) Results: the prevalence of major depressive disorder (MDD) using the PHQ-9 scale showed that minimal degree of depression (0-4 points) was seen in residents of Kurchum district more often (199 people - 81.2%) than in the residents of Abay and Borodulikha districts (65.7% and 65.8%, respectively). A similar pattern was observed in case of moderate (10-14 points), severe (15-19 points) and extremely severe (20-27 points) degrees of depression: their frequency in the control group was lower than in the study group. An assessment of the severity of generalized anxiety disorder (GAD) in the study groups showed a significant excess of mild to moderate anxiety levels in both Abai and Borodulikha districts in comparison with indicators of the control group (23.2%, 23.4% and 13.1% respectively for a mild degree and 4.3%, 3.6% and 2.9% respectively for moderate anxiety). Conclusions: our results confirm the hypothesis that exposure to radiation due to the prolonged residence in ecologically unfavorable territories, negatively affects the prevalence and severity of a major depressive disorder and generalized anxiety disorder among the exposed individuals.