Meta-analyses show that unemployment is associated with physical and mental illness, in particular depression (e.g. [
18,
22,
36]) and suicide [
35]. Chen et al. [
11] found in their study that long-term unemployed have more psychiatric symptoms than the short-term unemployed. The reduced activity of the affected persons, what is typical for depression, decreases the chances of reemployment while in turn, symptoms of the individual (lower self-esteem, more pessimistic, more depressive) and social costs increase [
47]. Hollederer [
26] showed longitudinal that psychosocial stress increases for the long-term unemployed and Gordo [
21] found that older persons are suffering more from joblessness than younger people. Moreover, Bühler et al. [
9] showed that older, long-term unemployed persons are undertreated and heavily burdened. Within their sample, 70% of the participants were affected by depression (depression, dysthymia or double depression), and 61% of these were without any treatment or disorder-specific treatment. In 2009, Liwowsky and colleagues reported prevalence rates of 38% in a comparable sample for depressive disorders. These and other authors argue that depressive symptoms such as poor self-esteem or lack of motivation are major barriers to getting a job, retaining a job or both [
7]. However, depressive disorders can be treated effectively by psychological and pharmacologic therapies [
14,
16]. According to the Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM V; [
3]), major depression is associated with heavily impairment and burden. Apart from a full-blown major depressive disorder, there are subjects suffering from depressive symptoms below that clinical threshold, who are not being identified as depressive. So called minor depression, defined as “depressed affect and at least one of the other eight symptoms of a major depressive episode” (DSM V), is a prevalent disorder associated with impairment of quality of life and functional disability [
24] or even suicidality [
42]. Other terms for this disorder are subsyndromal, subthreshold, or subclinical depression. Rodriguez et al. [
38] reviewed literature between 2001 and 2011 and found a wide heterogeneity in definition and diagnostic criteria. The authors concluded that patients falling below the diagnostic threshold suffer from difficulties in functioning, and experience a negative impact on their quality of life. In addition, some researchers argue that major depression’s criteria are questionable, because not all depressed cases in need of treatment are identified (e.g. [
4,
28]). Furthermore, Cuijpers and van Straten reported in their meta-analytic review [
13] that subjects with minor depression carry a high risk of developing major depressive disorder. Those findings had already been reported in a longitudinal study by Sherbourne et al. [
39]. So far, prevalence rates of minor depression are only known for the general population: in 2006, Martin and colleagues reported a rate of 5.4% for minor depression (and 3.8% for major depression). These authors also found the Patient Health Questionnaire [
32] being a useful tool to identify major and minor depression in the general population.
A further interesting aspect is that some symptoms of minor depression could be more important than others: Judd and Akiskal [
27] found sleep disturbances and fatigue being more frequent than other symptoms within people from the general population suffering from minor depression. However Baumeister and Morar [
6] found depressed mood and insomnia/hypersomnia (sleep disturbances) to occur more often than other symptoms within that group. They also found that anhedonia is
the symptom that distinguishes people with a major depression from people with a minor depression best. If we knew which symptoms in minor depression among the specific group of older, long-term unemployed are particularly frequent, we knew which symptoms we must pay particular attention to. We therefore postulate that more frequent symptoms are more important than less frequent symptoms, to identify people in need.
That is why one of our specific research questions is, which symptoms - people with minor depression suffer from - are more frequent than others within the specific group of older, long-term unemployed. Because so far in the literature it has been shown that in the general population sleep disturbances, fatigue and depressed mood are more frequent than other symptoms in minor depression, but there are no studies examining minor depression and frequent symptoms within older, long-term unemployed. We therefore chose an explorative proceeding because literature is not in consensus so far.
Furthermore we already know that minor depression is a prevalent disorder associated with functional disability, impairment of quality of life and intense healthcare use, and that 22% of older, long-term unemployed people suffer from major depression. But prevalence rates for minor depression in this population are unknown so far. Therefore reporting prevalence rates for minor depression in older, long-term unemployed is the main aim of this study. These findings are important because it is well known that unemployment is associated with mental illness - especially depression - and that minor depression increases the risk of developing a major depression. This in turn reduces the chances of reemployment for the people who suffer from depression. But reemployment not only is a protection factor for health [
21], but also is a main aim by politicians and physicians because the reemployment chances decrease with an increasing duration of unemployment [
21] and in the same time the social costs increase, too [
47]. Beside that the individual costs increase because minor depression is associated with considerable functional morbidity and suicidality.