Influence of established and subjectively perceived as well as evaluated individual characteristics on the utilization of mental health services among individuals with depressive disorders: protocol of a longitudinal study examining how to supplement the “behavioral model of health services use” and on need-congruent use of mental health services

In Germany, the 12-month prevalence of diagnosed unipolar depression is 10.6% in women and 4.8% in men [1]. In addition to the load of symptoms, depression is associated with impaired quality of life and functioning [2, 3]. Due to its frequency and complex consequences depression is a challenge for the health care system. In Germany, outpatient, day-care and inpatient services are being provided for individuals suffering from depression [4], and an established guideline specifies which treatment is appropriate [5]. Especially for people with moderate or severe depressive symptoms and people with persistent mild depressive symptoms (> 2 weeks), treatment is indicated. In these cases, psychotherapy and/or pharmacotherapy [5] would be appropriate, according to the guidelines. However, analyses from the German Health Interview and Examination Survey for Adults (DEGS) show that approximately one out of every three (34.6%) who met the diagnostic criteria for major depression in the previous 12 months used mental health services [6]. There is a relevant gap between need and mental health services use that has to be bridged.

An established generic model, the “Behavioral Model of Health Services Use” by Andersen (ABM) [7], can be used to further investigate utilization behavior [8]. The model, which has been continuously developed since the 1960s, describes various determinants of health behavior and health-related outcomes. The most recent version [7] focuses on predisposing factors, enabling factors and need as essential contextual and individual predictors of health behavior and thus health services use.

Contextual characteristics describe environmental variables such as the presence and accessibility of facilities. Age and gender, educational status, occupational status, ethnicity, social relations and health beliefs are established predisposing individual characteristics [8]. Likewise, at the individual level, income, insurance status, presence of a permanent general practitioner (GP), means of transport, travel time and waiting time are established enabling factors, while symptoms and subjective needs are established need factors [8]. In this model, the subjective perception of those affected is considered in personal health beliefs and perceived needs. In empirical studies, however, these subjective characteristics have only rarely been investigated [9].

A systematic review [10] focusing on help-seeking individuals with major depression indicates that men (e.g., [11]), young adults and elderly people (e.g., [12, 13]), ethnic minorities (e.g., [14]) and people with lower levels of education (e.g., [13]) have a higher risk of not receiving professional health care (predisposing). With regard to need factors, positive correlations were reported between mental health service use and the severity of symptoms (e.g., [11]), duration of disease (e.g., [14]) and presence of comorbid anxiety disorder (e.g., [15]). Health beliefs have only been investigated in 5 of 39 included studies [10]. Similarly, Roberts et al. [16] found only two studies considering stigma and no study considering mental health literacy as an enabling factor for service use for individuals with mental disorders. However, a recent study showed that biomedical causal beliefs are related to need and intention to seek help in individuals with untreated mental illness [17]. In addition, a qualitative synthesis conducted to understand help-seeking behavior in depression emphasizes the importance of subjective beliefs [18]. In addition to the lack of research with regard to subjective beliefs, the cross-sectional design of most of the studies limits their value for explaining mental health service use [10, 16].

In summary, Germany provides a range of mental health services, but only one in three individuals experiencing symptoms of major depression seeks professional help. Therefore, it is of particular interest to better explain the process of mental health service use and especially take into account subjective beliefs and perceived need.

The study outlined here is intended to provide insight into the theoretical basis of mental health services use and to contribute to specifying the characteristics described in the ABM. To the best of our knowledge, this is the first representative, longitudinal study that collects diagnoses by conducting diagnostic interviews and investigates the association between subjectively perceived and evaluated characteristics and the mental health service use of people with depressive disorders. Thus, after completion of the study, a more sophisticated and empirically tested model will be available to explain the mental health service use of people with depression. Our findings, although derived from the German context, will be valuable internationally, as evidence regarding the role of subjective depression beliefs and perceived need in the process of help-seeking and mental health services use is weak [10, 16]. Our supplemented version of the ABM can be examined in other contexts; moreover the ABM explicitly includes contextual characteristics so that further research can take these into account.