Domain-specific associations between disability and depression, anxiety, and somatization in primary care patients

Highlights

• Non-severe emotional disorders are associated with substantial disability.

• Depression, anxiety and somatizations are related to distinct domains of disability.

• Depression intensity was the best predictor of all aspects of impaired functioning.

Abstract

This study explores the associations between different disability domains and the most prevalent symptoms of mental disorders in primary care patients (i.e. depression, anxiety, and somatization). A total of 1241 participants from 28 primary care centres completed self-report measures of depression, anxiety, and somatization. This same sample also completed the Sheehan Disability Scale (SDS) to assess functional impairment in work, social life, and family life domains. Associations between the symptoms and each disability domain were examined using hierarchical regression analyses. Depression emerged as the strongest predictor of all three disability domains. Somatization was associated only with the work domain, and anxiety was associated only with the family life domain. Clinical symptoms explained a greater proportion of the variance than sociodemographic variables. In primary care patients, depression, anxiety and somatizations were associated with distinct domains of disability. Early provision of effective treatments in the primary care setting may be crucial to reduce the societal burden of common mental disorders.

Introduction

Depression, anxiety and somatoform disorders are the most prevalent disorders in primary care settings (Roca et al., 2009, Toft et al., 2005). Results from epidemiologic studies in primary care and community health service settings have shown that common mental disorders involve substantial functional impairment (Alonso et al., 2004, den Boeft et al., 2016, Roy-Byrne, 1996). Anxiety and mood disorders have been associated with levels of disability that are similar to or higher than those observed in common chronic conditions (Buist-Bouwman et al., 2006).Somatoform disorders have also been associated with high levels of disability (Harris et al., 2009, Mack et al., 2015), although evidence on this is sparse.

Mental health problems are now the biggest single cause for a disability benefit claim in most countries (OECD, 2010). Not surprisingly, the societal costs of common mental disorders are substantial (Ruíz-Rodríguez et al., 2017; Whiteford et al., 2013). In Spain, the costs of depressive, anxiety and somatoform disorders have been estimated at 22.8 € billion (equivalent to almost 2% of the country's gross domestic product), more than half of which is due to indirect costs such as permanent or temporary absence from work or early retirement (Pares-Badell et al., 2014).

Large-scale population surveys such as the World Mental Health Surveys (WMHS) and the US National Comorbidity Replication Survey (NCS-R) have reported that mental disorders are associated with disability (Alonso et al., 2011, Druss et al., 2009, Gadermann et al., 2012, Merikangas et al., 2007). Likewise, primary care studies have corroborated these findings in patients with common mental disorders (Fernandez et al., 2010, Grandes et al., 2011, Hanel et al., 2009, Leon et al., 1997, Olfson et al., 1997). However, most of these large-scale general population or primary care studies examining the relationship between disability and mental disorders are based on syndromes or disorders rather than individual symptoms. It is important to note that subthreshold mental disorders are also associated with considerable disability and are common in people who also met the full criteria for other axis I disorders (Olfson et al., 1996). Therefore, in studies using diagnostic categories, it is not clear which symptoms are specifically associated with functional impairment even when these studies include only individuals who fulfil the criteria for just one mental disorder. Understanding these specific relationships is crucial to detect, and ultimately to prevent, mental health-related disability. Research in this setting is particularly important given that approximately one third of primary care visits are explicitly motivated by psychological problems (Wittchen et al., 2003) and up to 90% of people diagnosed with common mental disorders are treated by a general practitioner (GP) (National Institute for Health and Care Excellence, 2011).

In this context, we conducted this study in a large sample of primary care patients to examine the associations between specific domains of disability (i.e. work, social and family life) and depression, anxiety, and somatization, which are the most prevalent symptoms in this population.