INTRODUCTION
Given that a large portion of mood disorders have recurrent courses, it is important to find and control the factors that predict recurrence and relapse of mood episodes. Adverse life events can have negative effects on onset and course of mood disorders, including depressive disorder (DD) and bipolar disorder (BD) [
1,
2]. For this reason, how to coping with daily stressor can be important in managing mood.
As a part of adaptational processes, people tend to develop habitual methods of managing stressful situations and coping with their emotional turmoil [
3]. In most cases, these habitual methods will help individuals manage stressful situations, but they are not all equally efficient at this task. Some methods only can make matters worse [
4]. In this reason, it may be important to identify these habitual ways of coping, assess how effectively this will handle stressful situations, and correct them if necessary [
5].
Endler and Parker have identified three coping styles: taskoriented, emotion-oriented and avoidance-oriented coping. Task-oriented coping describes task-oriented efforts aimed at solving the problem, cognitively restructuring the problem, or attempts to alter the situation. Emotion-oriented coping describes emotional reactions that are self-oriented, aimed to reduce stress. It includes emotional responses such as selfblaming, getting angry and rumination. Avoidance-oriented coping describes activities and cognitive changes aimed at avoiding stressful situation and alleviate stress [
6].
Research indicated that patients with depressions tend to use maladaptive or emotion-oriented strategies [
7,
8]. Problem solving (task-oriented coping) was related to less depression and emotion discharge (emotion-oriented coping) was associated with depression [
9]. Other researchers found that emotion and avoidance-oriented coping are positively correlated with an increase in depressive symptomatology while task-oriented coping is negatively correlated with the later variable [
10,
11].
Most of the studies on the coping in mood disorders were conducted with major depressive disorder patients. A recent review of emotion regulation strategies in BD concluded that BD endorses putatively maladaptive strategies for regulating negative affect (i.e., rumination, self-blame, suppression and catastrophizing) more than non-clinical controls [
12]. Another study on coping in BD found that bipolar patients were more likely to ruminate about positive affect and engage in risk taking than DD patients when they are faced with negative affect. Coping style differences were even observed between BD subtypes (Bipolar I and II) [
13].
These findings suggest that DD and BD should use different coping strategies which could be affected by mood states and vice versa. To date, however, no studies to our knowledge have examined coping styles, mood states and their inter-relationship in both DD and BD clinical sample. Observing the longitudinal course BD, depressive episodes and symptoms prevail over manic or hypomanic episode [
14]. Therefore, it was considered that the study of depressive episode, which occupies most of the natural history of the disease, would be more useful in the study of coping with stress.
This study aimed to determine the similarities and differences in the coping styles between DD and BD, in association with severity of depression. Moreover, as culture is a fundamental context in shaping coping styles of individual, and since only a few studies on coping with stress in Koreans have been conducted to date, this study on stress coping in Koreans will be more meaningful.
DISCUSSION
This study investigated the difference of coping strategies between bipolar disorder patients and depressive disorder patients. To investigate them more precisely, we analyzed the relationship between depression and coping in subjects with mood disorders.
According to the previous studies on the relationship between coping style and depression, increase in depressive symptomatology is associated with fewer task oriented coping behaviors and greater emotion and avoidance oriented coping behaviors [
10,
11]. In accordance with the previous studies, our results found a significant negative correlation between the level of depressive symptomatology and task oriented coping styles and a significant positive correlation between the former variable and emotion oriented coping style. On the other hand, in the case of avoidance oriented coping styles, results were opposite to what was expected. The level of depressive symptomatology and avoidance oriented coping styles were negatively correlated. These findings were in an agreement with a previous research which conducted with a sample of psychiatric outpatients including all patients regardless of their diagnosis, not only the depressive disorder patients [
21].
Most studies examining the relationship between depressive symptoms and coping styles, subjects were limited to depressive disorder patients, excluding bipolar disorders and other psychiatric disorders. However, in the previous study we mentioned above, subjects were not limited by their diagnosis. Such differences may explain discrepancies between two studies. According to our hypothesis, coping strategies may be different depending on their diagnosis, and the association of coping strategies with depression could be revealed more accurately when we consider their diagnosis.
It was reported that patients with high levels of depressive symptoms use more emotion-oriented coping strategies [
10,
22]. Emotion-oriented coping describes emotional reactions that are to reduce stress, yet these coping styles seem to be relatively ineffective in managing the stress and are associated with an increased risk of relapse of mood episodes [
23]. These findings are in line with our results. We found that subjects who are high on depressive symptoms, as assessed by the BDI, engaged in more emotion-oriented coping than those who are low on depressive symptoms in both diagnostic groups (BD and DD).
As we investigated the difference of coping strategies between BD and DD, we found that a more avoidant and taskoriented coping style were used in BD subjects. Especially greater use of avoidant coping was found even after controlling for the severity of depression.
Unlike emotional coping strategies, items of task (e.g., planning, attempts to solve the problem) and some items of avoidance (e.g. seeking social contact) require a high level of energy or activity, which is generally classified as active coping [
24]. In other words, the depressive states mainly using task and avoidance-oriented coping might reflect depression with high level of energy, and it might be associated with a depressive mixed state. The study of Sato et al. [
25] pointed out that depressive mixed state is particularly frequent in depression of BD than depression of DD. Our results might be understood in the same context. However, in order to draw these conclusions, more precise future studies are needed.
Another possible explanation for these findings may relate to their extroversive personality. BD patients tend to have higher levels of extraversion and better social coping than DD patients [
26], and these characteristics may lead them to use more task and some kind of avoidant coping [
24].
In a study of older age bipolar disorder subjects, better executive functioning was associated to more active coping [
27]. In this study, the Utrecht Coping List (UCL) was used to access the coping strategies. Before applying these results to our study, we need to compare the items included in each category of the two different scales (the UCL and the CISS). In the study we mentioned above, the subscales of active approach (i.e., finding out all about the problems, considering different solutions to the problems) was interpreted as active coping, and the subscales avoidance (i.e., being totally pre-occupied with the problems, worrying about the past) was interpreted as passive coping. However, the items of the UCL’s active approach are classified as task-oriented coping, and items of the UCL’s subscales avoidance are classified as emotion-oriented coping in the CISS. Other subscales including problem sharing, palliative reactions of the UCL are categorized as avoidance-oriented coping in the CISS. Therefore, when interpreting the results of the study with the CISS categories, better executive functioning was more associated to task-oriented coping.
Our data has shown a positive correlation between education level and task-oriented coping, and it might be due to a better executive function of the subjects with high education level. A recent study investigated the differences in executive function between drug-naïve subjects with depressive episode in both BD and DD found that the executive function in DD patients was worse than in BD patients [
28]. With the results of those studies, it can be deduced that BD patients have better executive function and use more active coping like task and social diversion of avoidance-oriented coping.
Another interesting new finding is that once the symptoms of depression get greater, the difference between BD and DD coping strategies is reduced. This may suggest that when the depressive symptoms are mild, there is a large difference between the two diagnostic groups when choosing a coping strategy, but when the symptoms gets severe, the subjects of both groups failed to cope with the stress properly and the difference is reduced.
As shown in
Figure 2B, in the depressive state, both BD and DD groups used emotion-oriented coping, which is known to be maladaptive, significantly more than task and avoidance. The results of this study do not tell what is the cause or effect, but again confirm that emotion-oriented coping is associated with depression.
This study was limited due to the use of a cross-sectional design, disallowing examination of changes in coping styles over time. The cross-sectional design provided a limited insight into the complex relationships between coping strategies, depressive symptoms and the two diagnostic groups. There is no information on how coping changes when a depressed state changes in each subject, and there is a limit to the interpretation because it cannot be compared with the characteristics of the general population. Second, another limitation is the lack of data on variables that may affect coping, such as cognitive patterns, temperament, medication, drug compliance and the time of the first onset. Therefore, the effects of these variables could not be ruled out. A further limitation was the use of selfreport questionnaires, which is inherently more subject to error than clinician-rated measures.
Despite these limitations, the present investigation increases understanding of a relationship between psychiatric diagnosis (BD and DD) and their coping strategy. Coping strategy could be a target for selective prevention targeting subgroups. Subgroups can be classified by their age, gender and personality [
23], and based on the present study, depressive symptom severity and psychiatric diagnosis as well. Recognize the maladaptive coping and changing to the adaptive coping could ameliorate their mood symptoms and change the course of the disease.
Studies about the coping strategies measured coping using various scales, and each of those scales classified coping strategies in different way. This makes interpretation difficult. Developing reliable and valid tools that assesses how people cope with stressful situations and unifying the measurements are necessary. Given the limitations of the present study, longitudinal studies using precise scales for coping styles in BD, DD patients and healthy controls are required for further validation.