Prevalence and Sex-Specific Associated Factors of Depression and Generalised Anxiety Disorder Symptoms in the General Adult Population of Latvia. Summary of the Doctoral Thesis
Authors:   ,   Rīga Stradiņš University, Vinogradova Vineta Viktorija 
Published: November 2023

Introduction. Anxiety and mood disorders are the most prevalent mental disorders worldwide. Among them, generalized anxiety disorder stands out as one of the most commonly diagnosed anxiety disorders, while depression accounts for the majority of mood or affective disorders. Often, these two disorders co-occur or are comorbid. Global data indicate that both depression and generalized anxiety disorder often are underdiagnosed, with only a minority of patients receiving appropriate treatment according to established guidelines. If left untreated, depressive or generalised anxiety disorders have a significant impact on the public health system, on the quality of life and work capacity of each individual patient, and increase the economic burden on the country in terms of direct medical costs, indirect workplace costs and suicide-related mortality costs. To address this issue and facilitate early recognition and timely treatment of these disorders, it is crucial to understand their prevalence within the general population. Additionally, identifying both general associated factors and region-specific factors associated with the cultural and socio-economic environment is necessary. In the case of Latvia, generalized anxiety disorder has never been systematically screened in the general population, and the current prevalence of depression has not been established for over a decade. Furthermore, considering that both disorders are twice as prevalent in women, it is essential to explore gender-specific factors associated with these disorders. Hence, the objective of this thesis study was to determine the prevalence of generalized anxiety disorder and clinically significant depressive symptoms in the general population of Latvia and identify gender-specific associated factors for these disorders. Methods and materials. Specially trained professional interviewers conducted computer-assisted face-to-face interviews with a nationally representative sample of the Latvian adult population (n = 2687) between November 2019 and March 2020. The presence of generalized anxiety disorder symptoms was assessed using the Generalized Anxiety Disorder Questionnaire 7 (GAD-7) self-rating scale. A score of 10 or higher was established as the threshold for identifying cases of generalized anxiety disorder. Clinically significant depressive symptoms were identified using the Patient Health Questionnaire 9 (PHQ-9), with a score of 10 or above serving as the diagnostic cutoff. To assess co-existing psychiatric disorders, the MINI International Neuropsychiatric Interview (MINI) 7.0.2. version modules were employed. The respondents' socio-demographic data, health service use and other health-related information, as well as information on health self-assessment were obtained from a questionnaire specifically designed for this study, which was tested in focus groups with the target population before the start of the fieldwork. Self-rated health was measured by respondents answering the question “How do you rate your current health status?” with answers offered “good”, “rather good”, “moderate”, “rather poor” or “poor”. Separate stepwise binary logistic regression analyses were conducted for each gender to identify factors associated with these disorders. Results. According to the PHQ-9 questionnaire, clinically significant depressive symptoms were found in 6.4 % (95 % CI 5.8–7.6) of study participants. The point prevalence of depressive symptoms was statistically significantly higher among women: clinically significant depressive symptoms were found in 7.7 % (95 % CI 6.4–9.0) of women and 4.8 % (95 % CI 4.2–6.7) of men, p = 0.003. The prevalence of symptoms of generalised anxiety disorder according to GAD-7 in the Latvian population was 3.9 % (95 % CI 3.2–4.6). The point prevalence of symptoms of generalised anxiety disorder was significantly higher among women [4.9 % (95 % CI 3.8–5.9)] than among men [2.7 % (95 % CI 2.0–3.8)], p = 0.004. When adjusted for all main sociodemographic characteristics simultaneously, gender remained a statistically significant associated factor for depression and generalised anxiety symptoms, which justified the identification of associated factors separately within gender groups. Presence of suicidal ideation, self-harm and suicidal behaviour according to MINI increased the odds ratios for both depression and generalised anxiety symptoms in both sexes: 3.86 (95 % CI 2.15–6.95) and 3.10 (95 % CI 1.57–6.14) for depression aOR and generalised anxiety disorder symptom aOR, respectively, in women; 5.56 (95 % CI 2.51–12.34) and 14.73 (95 % CI 4.56–47.61) for depression aOR and generalised anxiety disorder symptom aOR, respectively, in men. In both female and male populations, clinically significant depressive symptoms increased the odds of generalised anxiety disorder symptoms: for women aOR 24.43 (95 % CI 12.46–47.88), for men aOR 130.28 (95 % CI 30.60–554.68); and vice versa the presence of generalised anxiety disorder symptoms increased the odds ratio of clinically significant depression in both women [aOR 24.25 (95 % CI 11.91–49.39)] and men [(aOR 130.28 (95 % CI 30.60–554.68)]. Poor self-rated health was significantly associated with higher odds ratios for depressive symptoms in both sexes: aOR 7.38 (95 % CI 3.31–16.47) for women and aOR 29.76 (95 % CI 9.74–90.91) for men. For both sexes, the generalized anxiety-associated factors were more frequent use of health services: for women, seeing a specialist 3–4 times in the last year [aOR 4.39 (95 % CI 1.65–11.66)] and ≥ 5 times per year [aOR 3.24 (95 % CI 1.14–9.23)], and calling the ambulance 3 or more times in the last year [aOR 4.21 (95 % CI 1.14–15.45)]. For men, visits to GPs 3–4 times in the last year [aOR 6.49 (95 % CI 1.08–38.91)]. For women only, the depressive disorder associated factors were: substance (non-alcohol) use disorder in the last year according to MINI [aOR 6.19 (95 % CI 1.88–20.38)], at least one eating disorder diagnosed by MINI [aOR 11.24 (95 % CI 1.98–63.76)], being a member of an ethnic minority [vs. Latvian, aOR 3.06 (95 % CI 1.49–6.28)], economically inactive status [vs. working woman, aOR 4.01 (95 % CI 1.50–10.71)], and 1–2 ambulance calls during the last year [aOR 2.10 (95 % CI 1.06–4.17)]. Women with 2 or more children had statistically significantly lower odds of suffering from depressive symptoms [vs. no children, aOR 0.35(95 % CI 0.12–0.98)]. Only in males antisocial personality disorder increased the odds of depression [aOR 7.89 (95 % CI 2.63–23.62)]. The odds ratio for clinically significant depressive symptomatology was lower in men living in Latvian towns, except Riga [vs. rural areas, aOR 0.25 (95 % CI 0.09–0.67)]. Female-only associations of generalised anxiety disorder were syndromes or symptoms of abnormally elevated mood at the moment of interview or previously in life [aOR 9.39 (95 % CI 2.96–29.76)] and having one child [vs. no children, aOR 3.63 (95 % CI 1.65–8.00)]. In the male population, smoking tobacco and nicotine-containing products episodically or regularly was associated with generalised anxiety symptoms [vs. never smoked, aOR 6.77 (95 % CI 1.50–30.49)]; Lower completed education was associated with lower odds of generalised anxiety symptoms [vs. higher education, aOR 0.12 (95 % CI 0.02–0.79)]. Conclusions. The point prevalence of clinically significant depressive symptomes in the general adult population in Latvia is 6.4 % and is higher among women than men: 7.7 % and 4.8 % respectively, which is consistent with the results of a study conducted in Latvia in 2011 and global data. The point prevalence of the symptoms of generalised anxiety disorder in the Latvian population is 3.9 % and is statistically significantly higher among women (4.9 % ) than among men (2.7 %), which is in line with the results of international studies. The hypothesis of the study was confirmed and as a result, universal gender-unspecific and gender-unique associations of depressive and generalised anxiety disorder symptoms were identified. In the general population, suicidal behaviour, clinically significant depression and symptoms of generalised anxiety were shown to be three psychiatric disorders that were statistically significantly associated with each other in both sexes, while in the male population suicidal behaviour or ideation was associated with higher odds ratios for depression than for women and especially higher odds ratios for generalised anxiety symptoms. The absolute majority of men with generalised anxiety disorder also had clinically significant depression and/or suicidal behaviour. Thus, when working with Latvian men in practice, professionals should pay special attention to symptoms of anxiety, nervousness, and tension, which can serve as indicators of possible comorbid depression and suicidality, and help to recognise these disorders early and reduce the risk of fatal suicidality in men. The study data support significant associations with depression for the following target populations already described in the Latvian Centre for Disease Prevention and Control’s “Clinical Algorithm for Depression Recognition, Management, Treatment and Care”: people with a history of suicide attempts or self-harm, anxiety disorders, poor physical health and health self-esteem, and substance abuse. The Latvian Centre for Disease Prevention and Control’s “Clinical Algorithm for the Recognition, Management, Treatment and Care of Depression” can be supplemented with additional target populations for depression screening: women with eating disorders, ethnic minorities (especially women), economically inactive women (on maternity leave or unpaid worker in family business), women with ambulance calls in the last year, and men with antisocial personality traits: anger, irritability, neglect of social norms. The existing algorithm should highlight that substance use disorders are particularly associated with depression in women in the Latvian population. From a practical perspective, these results highlight the need for policy makers to pay attention to making depression prevention interventions and information accessible to ethnic minorities. Having two or more minor children is a protective factor for depression in women and should be highlighted in family planning information materials. Generalized anxiety disorder was associated with more frequent use of health services in both sexes: for women, frequency of visits to specialist doctors starting from 3×/year and ambulance calls 3 or more times in the last year were associated with generalised anxiety. For men, these were visits to general practitioners 3–4 times in the last year; this finding both highlights the target populations for screening and indicates a potential reduction in the burden on the healthcare system through early recognition and treatment of these disorders. The unique associated factors of generalised anxiety disorder for women were pathologivally elevated mood syndromes or symptoms and having one minor child, while for men it was smoking tobacco and nicotine-containing products. These identified associated factors of generalised anxiety disorder may serve as indicators for identifying screening target populations for a similar, currently underdeveloped, future algorithm for the recognition and treatment of anxiety disorders. The study of Doctoral Thesis was conducted within the framework of the European Social Fund project “Complex Health Promotion and Disease Prevention Measures” (identification No 9.2.4.1/16/I/001). This Doctoral Thesis has been developed with financing from the European Social Fund and Latvian state budget within the project No. 8.2.2.0/20/I/004 “Support for involving doctoral students in scientific research and studies” at Rīga Stradiņš University, Latvia. 3.2 Health Sciences; Sub-Sector – Psychiatry. Keywords: depression, generalised anxiety disorder, prevalence, sex-specific associated factors, general population.