Psychological Distress Among Sisters of Young Females With Eating Disorders

Abstract

There is limited research on sibling relationships in families with an eating disorder (ED) child. The aim of the study was to examine the association between sibling relationships, sense of coherence, psychological distress and depression among healthy sisters of females with or without EDs. Participants were 60 females (13-31 years old): 30 who had a sister with an ED (study group) and 30 without (controls). Participants completed self-report questionnaires: depression, psychological distress, sibling relationships, and sense of coherence. Results showed that the study group had significantly higher levels of depression and negative sibling relationships than the control. A significant negative correlation was found between sense of coherence and depression. The study model shows that belonging to one of the groups, sense of coherence, and sibling relationships were significant predictors of the healthy sisters’ depression level. It is suggested that when sister has an ED, negative sibling relationships can influence the psychological condition of her healthy sister.

Keywords

eating disorders sisters family sibling relationships sense of coherence

In recent decades, there has been a significant increase in the prevalence of eating disorders (EDs), the most common of which are anorexia nervosa, bulimia nervosa, and eating disorders not otherwise specified (Swanson, Crow, Le Grange, Swendsen, & Merikangas, 2011; Hoek & Van Hoeken, 2003). EDs are especially common among teenage girls and young women in the modern Western world (Katzman, Hermans, Van Hoeken, & Hoek, 2004; Ogden, Carroll, Curtin, Lamb, & Flegal, 2010) and are associated with high morbidity and mortality rates (Fairburn & Harrison, 2003; Hoek, 2006). The etiology of EDs is multifactorial and includes genetic-biological, socio-cultural, and psychological–familial factors (Klump, Kaye, & Strober, 2001; Murphy, Troop, & Treasure, 2000). Considerable attention has been paid to the family’s role, particularly the parent–child interaction, in the etiology of EDs (Latzer, Hochdorf, Bachar, & Canetti, 2002B; Latzer, Lavee, & Gal, 2009; Le Grange, 2005; Zabala, Macdonald, & Treasure, 2009).

The importance of the sibling subsystem in general, and in EDs in particular, has also gained increasing recognition over the years. Sibling relationships are among the longest standing relationships in a person’s life and are considered to be one of the most significant, second only to the parent–child relationship (Powell & Gallagher, 1993). Through relationships with siblings, children have the opportunity to learn about themselves and others (Dunn, 2000; Minuchin et al., 1975; Minuchin, Rosman, & Baker, 1978). In addition, sibling dynamics affect developmental processes, such as establishing identity and separateness (Bank, Kahn, & Kahn, 2003), developing sensitivity, understanding the self and the other, and learning social skills for conflict resolution (Dunn, 1992; Furman & Buhrmester, 1985). Moreover, these relationships have an impact on personality and coping abilities in crisis situations, such as illness (Karwautz et al., 2001; Latzer, Ben-Ari, & Galimidi, 2002A; Senel & Hakkok, 1996; White, 2001).

Research regarding the influence of a child’s illness or disability on other family members (McLinden, Miller, & Deprey, 1991) has shown that healthy siblings who are living in the shadow of the illness, experience various difficulties that can have emotional, structural, familial, and social ramifications (Corrigan & Miller, 2004; Sharpe & Rossiter, 2002). The emotional difficulties experienced can range from no expression at all to symptoms of serious distress (Bailey & Simeonsson, 1988; Cuskelly & Gunn, 1993; Labay & Walco, 2004; Lindsey & Stewart, 1989; Sharpe & Rossiter, 2002; Shulman, 1988).

Only a few studies have been conducted on sibling relationships in families that have a child with an ED. The findings of these studies show that females with an ED project onto the relationships with their siblings in general and with their sisters in particular. Although rivalry exists, mainly between sisters, the sisters without the ED are significantly less competitive than those with the ED (Bank et al., 2003; Dunn, 1983; Latzer et al., 2002A; Sights & Richards, 1984; Stierlin & Weber, 1987; Vandereycken & Van Vreckem, 1992; Waters, Beumont, Touyz, & Kennedy, 1990).

Additional studies examining the perception of the sibling relationship from the point of view of the sister with an ED found that the nature of the relationship can predict an improvement in physical symptoms (i.e., weight gain). The more positive the relationship, the greater the likelihood of gaining weight (Dimitropoulos, Klopfer, Lazar, & Schacter, 2009; Karwautz, Rabe-Hesketh, Collier, & Treasure, 2002). On the other hand, a higher prevalence of ED was found among sisters of females with EDs, especially among twins (Halmi, 2002; Murphy et al., 2000). Hence, the healthy sisters are considered to be a risk group for developing EDs (de Leeuw, Snoek, van Leeuwe, van Strien, & Engels, 2007).

In addition to the quality of the sibling relationship, a “sense of coherence” is also considered to be an internal resource that can influence the coping strategies of individuals in various stress situations (Antonovsky, 1979, 1994). Sense of coherence is defined as a general orientation that reflects the range within which individuals can predict their external and internal environment, with the likelihood of events occurring as expected. As such, it is a coping resource that assists in adopting constructive and effective behaviors in accordance with the situation at hand (Antonovsky, 1979, 1987). According to Antonovsky’s (1979) salutogenic model for health and sickness, all individuals, at any given time, are located on a continuum between healthy, effective coping and pathological, ineffective coping. Sense of coherence determines the individual’s position on the health-sickness continuum and is made up of three interrelated components: cognitive (comprehensibility), behavioral (manageability), and motivational/emotional (meaningfulness). Individuals with a high sense of coherence will believe in their ability to cope effectively with various stress situations, will be more resilient in times of crisis, and will move along the life continuum in the direction of health (Antonovsky, 1983, 1987, 1993, 1994). This theoretical model has been supported by a number of empirical studies (Amirkhan & Greaves, 2003; Antonovsky, 1987; Söderfeldt, Söderfeldt, Ohlson, Theorell, & Jones, 2000). To the best of our knowledge, however, no studies have examined sense of coherence among individuals with EDs, and and certainly not among healthy sisters of young females with EDs.

Thus, despite the important role of sibling relationships in the personality development and structure of other family members, and the negative impact of having an ill child in the family, little research attention has been devoted to this subject with regard to EDs. The findings to date suggest that the sisters of young females with EDs may be more vulnerable to developing symptoms of an ED themselves. To the best of our knowledge, no studies have examined the correlations between the quality of sibling relationships, either positive or negative, sense of coherence, psychological distress and depression among the healthy sisters of young females with EDs. Moreover, whereas other studies have examined the sibling relationship from the point of view of the sister with an ED, the current study aims to focus on the perspective of the healthy sibling. The theoretical rationale underlying this family systems perspective is that EDs are both influenced by and affect family well-being.

Study Hypotheses

Hypothesis 1: Significant differences will be found between the study and control groups in the levels of psychological distress, depression, sense of coherence, and the quality of sibling relationships. Sisters in the study group (females who had a sister with an ED) will have higher levels of psychological distress, depression, and negative sibling relationships, as well as lower levels of sense of coherence and positive sibling relationships than the sisters in the control group (females who had a sister without an ED).

Hypothesis 2: A positive correlation will be found between the levels of psychological distress, depression, sense of coherence, and the quality of the sibling relationship. The higher the sense of coherence and the more positive the sibling relationship, the lower the levels of psychological distress and depression.

Hypothesis 3: Beyond groups, the quality of the sibling relationship and the level of the sense of coherence will predict the levels of psychological distress and depression.

Method

Participants

Participants were 60 females, aged 13 to 31 years (mean ± SD = 21.68 ± 4.17 years). Thirty of the participants (study group) had a sister with an ED (mean ± SD = 21.67 ± 4.48 years), with the following distribution: 10 with anorexia nervosa, 10 with bulimia nervosa, and 10 with EDs not otherwise specified (partial diagnosis of anorexia nervosa or bilumia nervosa). The other 30 participants (control group) had sisters without an ED (mean age ± SD = 21.70 ± 3.91 years).

No significant differences were found in the participants’ ages in the two groups, t(58) = 0.03, ns). The age difference between the sisters did not exceed 10 years, and all participants in both groups were the sister closest in age to the sister with or without the ED. All participants were born in Israel, and all pairs of sisters had lived under the same roof for at least five consecutive years prior to the study. Most participants (87%) lived with both parents; 5.5% lived with their mother and without their father because of divorce; 5.5% lived with their mother because of widowhood; and 2% lived only with their father. The majority (89%) of participants had between 1 and 2 siblings, 6% had 3 siblings, and 5% had 4 or more siblings.

Regarding education, most participants (73%) had graduated from high school, approximately 17% had completed junior high school, and 10% had completed or were in the process of some form of higher education (university or college). All participants’ parents had completed at least a high school education. As for occupation, 38% of the participants were employed, 19% were university students, 25% were in mandatory army service, 14% were still in high school, and 4% were unemployed. No significant differences were found between the groups in the distribution of demographic characteristics.

All of the participants’ sisters with ED had made an initial application for treatment within the past 2 years to three major ED clinics at hospitals in the central and northern regions of the country, and all had been diagnosed with EDs according to the Diagnostic and Statistical manual of Mental Disorders (fourth edition, text revision) diagnostic criteria (American Psychiatric Association, 2000). Exclusion criteria were reports of an ED or any other psychiatric disorder in the past. All sisters with EDs were in the active stage of the illness.

Instruments

Beck Depression Inventory

The Beck Depression Inventory (BDI; Beck, Ward, Mendelson, Mock, & Erbaugh, 1961; Beck, Steer, & Garbin, 1988) is a self-report questionnaire composed of 21 items that are designed to evaluate the affective, cognitive, physical, and behavioral aspects of depression, as well as to measure the respondent’s level of general depression in relation to other respondents. Each item is composed of four to five statements that are arranged according to increasing severity of symptoms. Respondents are requested to choose the most appropriate statement describing their condition in the past week. Scores for each item range from 0 to 3, and the total score indicates the severity of depression, with a higher score signifying a more severe level of depression. A score of up to 9 is considered normal, whereas a score more than 30 indicates severe depression. Reliability analysis of the BDI in previous studies revealed internal consistencies (Cronbach’s alpha) of .86 and .81 for psychiatric and nonpsychiatric samples, respectively. In the present study, internal consistency (Cronbach’s alpha) was found to be .79. Item 5 was removed from the calculation because of low internal consistency.

Brief Symptom Inventory

The Brief Symptom Inventory (BSI; Derogatis & Melisaratos, 1983) is a self-report questionnaire that aims to evaluate the psychological state of psychiatric and other patients. It includes 53 items, which were chosen from the 90 original items in the Symptom Checklis–90. Each item represents a symptom, and the participant has to mark the frequency of its appearance in the past month on a 5-point Likert-type scale, ranging from 0 = did not appear to 4 = appeared very frequently, with a high score indicating a high frequency of symptom appearance. In the present study, only the Global Severity Index was used, which is the mean of all 53 items. This index describes the respondent’s psychiatric state without relating to specific symptoms. The BSI was translated into Hebrew (Gilbar & Ben-Zur, 2002). General reliability of the Hebrew version was previously reported as .96 (Gilbar & Ben-Zur, 2002), and internal consistency (Cronbach’s alpha) of the BSI in the present study was .90.

Sibling Relationship Questionnaire

The Sibling Relationship Questionnaire (Furman & Buhrmester, 1985) questionnaire examines the quality of sibling relationships, using the following dimensions: friendship, intimacy, friendliness, admiration, guidance, similarity, love, antagonism, competitiveness, and jealousy. It includes 30 items ranked on a 4-point Likert-type scale, ranging from 1 = almost never to 4 = almost always. The questionnaire was translated into Hebrew (Eiron-Ayeg, 1996). The questionnaire’s dimensions were integrated into two subcategories: positive (Cronbach’s α = .93) and negative (Cronbach’s α = .81) sibling relationships. The higher the score for positive or negative sibling relationships, the higher the intensity of positive or negative relationships between the siblings. The participants in this study were asked to fill in the questionnaire in relation to the sister who was closest to them in age. Internal consistency (Cronbach’s alpha) for the entire questionnaire was .83 in the present study.

Sense of Coherence

The Sense of Coherence questionnaire (Antonovsky, 1987, 1994) was developed in Hebrew and English to examine the individual’s sense of coherence. It includes 29 items ranked on a 7-point Likert-type scale, ranging from 1 = never to 7 = always. The focus is on the three components of sense of coherence: comprehensibility, manageability, and meaningfulness. The participants are asked to choose the number that best describes their opinion or feeling in relation to each item. Antonovsky (1987) found that Cronbach’s alpha was between .84 and .93. The overall score is the mean score of the 29 items after reversing the 13 negative statements, with a high score indicating a high sense of coherence. Internal consistency (Cronbach’s alpha) for the entire questionnaire was .91 in the present study.

Procedure

Participants were recruited from three ED treatment institutions in Israel (two in the central region and one in the northern region). The study received the approval of the Helsinki Committee in the different hospitals. Informed consent was received first from the participants with ED and then from their sisters. In the case of minors, consent was also obtained from the parents. A meeting was then arranged with the participating sister, who was asked to complete a self-report in a face-to-face meeting, which lasted approximately half an hour. Following this, a convenience sample of participants was recruited for the control group in accordance with the relevant background variables (age, gender, residential area, and education).

In the study group of the 39 potential participants with sisters with EDs who gave their initial consent to participate in the study, only 30 actually participated. Nine asked to cease participation at the time they filled out the questionnaires. In the control group of the 45 participants who gave their initial consent to participate in the study, only 30 actually participated. No significant demographic differences were found between those who dropped out and those who fully participated.

Analysis

First, to examine differences between the study and the control groups regarding the study variables, five t tests were performed (Hypothesis 1). Second, Pearson correlation analyses were conducted between the two groups for the study variables (Hypothesis 2). Finally, hierarchical regression analyses were conducted to examine the predictors of psychological distress and depression by group, as well as the role of sense of coherence and sibling relationships (Hypothesis 3).

As the age range of the sample was 13 to 31 years, we controlled for age in the analyses (age as covariant) and found no significant influence.

The effect size estimate of the sample for the entire analysis in the current study according to Cohen’s d effect size was as follows: three research variables found to be low (psychological distress, .2; sense of coherence, .2; positive siblings’ relationships, .22), one variable found to be high .60 (negative siblings’ relationship), and one was medium .48 (depression).

Results

Differences Between the Groups Regarding the Study Variables

The first hypothesis predicts that significant differences will be found between the study and the control groups regarding the study variables: levels of psychological distress, depression, sense of coherence, and positive and negative sibling relationships. It was hypothesized that a higher level of psychological distress, depression, and negative sibling relationships, and a lower level of sense of coherence and positive sibling relationships would be found in the study group as compared with the control group. To examine this hypothesis, five t tests were performed. Table 1 presents the differences between the two groups for the study variables.

Table 1.

Differences Between the Study and the Control Groups in Study Variables (N = 60).

	Study Group (n = 30)		Control Group (n = 30)
Variable	M	SD	M	SD	t (df = 58)
Psychological distress	0.95	0.67	0.83	0.59	−0.75
Depression	8.17	5.57	5.27	5.71	−1.99*
Sense of coherence	4.63	0.87	4.85	0.83	0.98
Positive sibships	2.90	0.58	3.00	0.45	0.75
Negative sibships	1.99	0.54	1.67	0.53	−2.34*

Note. Psychological distress: 0 = did not appear, 4 = appeared very frequently. Depression: up to 9 is considered normal, more than 30 indicates severe depression. Sense of coherence: 1 = never to 7 = always. Positive and negative sibships: 1 = almost never, 4 = almost always.

p < .05.

Table 1 shows that significantly higher levels of depression and negative relationships were found among the participants whose sisters had an ED than among those whose sisters did not. On the other hand, no significant differences were found between the two groups in their levels of psychological distress, sense of coherence, or positive sibling relationships.

Correlations Between the Study Variables in the Study Group

The second hypothesis predicts that positive correlations will be found between psychological distress, depression, and negative sibling relationships, as well as between sense of coherence and positive sibling relationships. In addition, negative correlations will be found between psychological distress, depression, and sibling relationships, as well as between sense of coherence. Pearson correlation analyses were conducted between the two groups for the study variables.

Table 2 presents the correlations between the two groups for the study variables.

Table 2.

Correlations Between Variables in the Study Groups.

	Psychological distress	Depression	Sense of coherence	Positive sibships	Negative sibships
Psychological distress	—	0.59**	−0.69**	−0.44*	0.36*
Depression	0.80**	—	−0.50**	−0.43*	0.31
Sense of coherence	−0.83**	−0.78**	—	0.32	−0.29
Positive sibships	−0.13	−0.21	0.15	—	−0.03
Negative sibships	0.44**	0.52**	−0.36*	–0.47**	—

Note. Correlations for the study group are below the diagonal line; correlations for the control group are above the diagonal line. Psychological distress: 0 = did not appear, 4 = appeared very frequently. Depression: up to 9 is considered normal, more than 30 indicates severe depression. Sense of coherence: 1 = never to 7 = always. Positive and negative sibships: 1 = almost never, 4 = almost always.

*p < .05. **p < .01.

Table 2 shows that among the participants whose sisters had an ED, a reverse correlation existed between the positive and negative sibling relationships, whereas no such correlation existed among those whose sisters did not have an ED. That is, among healthy sisters, positive and negative relationships can exist side by side, but when one sister is sick, the existence of one (negative relationship) contradicts the existence of the other (positive relationship).

In addition, negative sibling relationships were more correlated with psychological distress and depression among the participants whose sisters had an ED than among those whose sisters did not. In contrast, positive relationships between the sisters were found to be negatively correlated with psychological distress and depression among the participants whose sisters did not have an ED, but not among those whose sisters did have an ED. A negative correlation was found between sense of coherence, psychological distress, and depression in both groups, though this correlation was stronger among those whose sisters had an ED than among those whose sisters did not.

Predictors of Psychological Distress and Depression by Group and the Role of Sense of Coherence and Sibling Relationships

It was hypothesized that the existence or nonexistence of EDs among the sisters, the quality of their sibling relationships, and their sense of coherence would predict the level of psychological distress and depression. This hypothesis was examined using hierarchical regression analyses. In the first step, the correlations between the study group (1) and the control group (0) and each of the outcome variables (psychological distress and depression) were examined. This stage demonstrates the degree to which belonging to one of the two groups explains the levels of psychological distress and depression.

In the second step, the independent variables of sense of coherence and sibling relationships were added. At this stage, both the positive and negative sibling relationship variables were entered into the model, reflecting the differences found between the two groups in the negative, but not in the positive, relationships. Differences between the groups were also found in the correlations between the two types of relationships and also between the relationships and the outcome variables. This stage indicates the contribution of these variables to explaining the variance in the outcome variables beyond belonging to one of the groups.

In the third step, the interactive variables between the study and the control groups and the explanatory variables were entered into the model. The evaluations at this stage show the degree to which a difference exists between the groups in the contribution of the independent variables to explaining the variance in the outcome variables.

Outcome Variables: Psychological Distress and Depression

Psychological Distress

Table 3 presents the findings of the first two steps of the hierarchical regression analysis, explaining the variance in the level of psychological distress. In the first step, belonging to the study group explained approximately 1% of the variance in the level of psychological distress (R² = .01). In the second step, the sense of coherence and the quality of the sibling relationship explained approximately 61% of the additional variance in the level of psychological distress. The third step made no additional statistically significant contribution to the explained variance (F change = 1.67, ns). In other words, the findings of the model were similar for the study and the control groups. Therefore, the higher the sense of coherence, the lower the level of psychological distress; and the more negative characteristics in the relationship between the sisters, the higher the level of psychological distress in both the study and the control groups.

Table 3.

Stepwise Hierarchical Regression to Predict Depression by Groups, Sense of Coherence, and Sibships.

Variable	B	β	t	R ²
Step 1
Group	2.90	.25	1.99*	.06
Step 2
Group	1.29	.11	1.14
Sense of coherence	−3.64	−.54	−5.26**
Negative sibships	2.13	.20	1.90^†
Positive sibships	−1.40	−.13	−1.27	.51

Note. Sense of coherence: 1 = never to 7 = always. Positive and negative sibships: 1 = almost never, 4 = almost always.

†

p < .10. *p < .05. **p < .01.

Depression

Table 4 presents the findings of the first two steps of the hierarchical regression analysis, explaining the variance in the level of depression. In the first step, belonging to the study group explained approximately 6% of the variance in the level of depression (R² = .06). In the second step, the sense of coherence and the quality of the sibling relationship explained approximately 45% of the additional variance in the level of depression. The third step made no additional statistically significant contribution to the explained variance (F change = 1.57, ns). That is, the findings of the model were similar for both the study and the control groups.

Table 4.

Stepwise Hierarchical Regression to Predict Distress Level by Group, Sense of Coherence, and Sibships.

Variable	B	β	t	R ²
Step 1
Group	0.12	.01	0.75	.01
Step 2
Group	−0.06	−.05	−0.52
Sense of coherence	−0.52	−.70	−7.79**
Negative sibships	0.19	.16	1.71^†
Positive sibships	−0.68	−.06	−0.64	.62

Note. Sense of coherence: 1 = never to 7 = always. Positive and negative sibships: 1 = almost never, 4 = almost always.

†

p < .10. **p < .01.

Table 4 shows that in the first step, the group variable explained the variance in the depression variable. That is to say, the presence of a sister with an ED predicts a higher level of depression in the sister without the ED. In Step 2, it can be seen that the higher the sense of coherence, the lower the level of depression. In addition, the more negative the sibling relationship, the higher the level of depression. These findings were true for the participants in both groups. Step 2 shows that a high level of coherence significantly reduced the influence of ED on the level of depression among the sisters without an ED.

Discussion

The aim of the present study was to examine the association between sibling relationships, sense of coherence, psychological distress, and depression among the sisters of young females with or without EDs. Relatively few studies are described in the literature on sibling subsystems in families that have a child with an ED (Blessing, 2007). Results of these studies show that the entire family experiences significant changes when the familial balance is disturbed, a phenomenon that is especially apparent in sibling relationships. Whereas previous studies have mainly addressed the difficulties from the perspective of the sisters with EDs (Dimitropoulos et al., 2009; Karwautz et al., 2002; Vandereycken & Van Vreckem, 1992), the current study focused on the healthy sisters. Moreover, most of the studies on sibling relationships have limited their investigation to the sisters’ negative relationship, whereas this study examined positive as well as negative aspects and the impact of sense of coherence on these relationships.

The main findings of this study indicate that among the sisters of young females with EDs, the levels of negative sibling relationships and depression symptoms were higher than among those whose sisters did not have an ED. On the other hand, no significant differences were found in their levels of psychological distress, sense of coherence, or positive sibling relationships. In addition, significant negative correlations were found between the sense of coherence and psychological distress and depression among the participants from both the study and the control groups.

Negative Sibling Relationships

The findings indicating a significantly higher level of negative sibling relationships among the study group as compared with the control group supports and strengthens previous studies (Brody, 1998; Feinberg & Hetherington, 2000). Several explanations can be suggested for these findings. The first is related to sibling rivalry for parental attention, which is often characterized by ambivalence, frustration, conflict, and frequent transitions between love–hate relationships (Bank et al., 2003; Blessing, 2007).

The second explanation is related to the extra responsibility required of the healthy sister to care for the sister with an ED and other siblings, which could lead to a combined sense of frustration, anger, jealousy, hatred, and fear of losing her sister (Latzer et al., 2002a). These ambivalent feelings often create a sense of guilt and fear and reinforce the vicious circle of closeness–distance, love and hate (McHale & Pawletko, 1992). This is especially true for EDs, as the illness is unlike other disabilities and illnesses, which are more structured and have external aspects. EDs are very difficult to understand, and there is a sense that everything depends on the sick girl, who makes no effort to eat and is deliberately making life difficult for everyone else. This situation can intensify the anger and make empathy and compassion difficult.

It is also possible that the healthy sister may have negative feelings about the fact that her sister is sick and she is not, a phenomenon that is described in the literature as “survivor’s guilt” (Bank et al., 2003). This explanation is supported by stress theory, which describes situations in which one family member is sick, especially one of the children, and the other family members, in particular the siblings, become “secondary victims,” expressed through their sense of burden. In the case of EDs, it is mainly the girls who carry the burden in relating to the sick sister (Beckham, Lytle, & Feldman, 1996; Bryant, 1989). Therefore, despite the sense of closeness created by this role, it is also accompanied by negative emotions, difficulties, and psychological distress.

Negative Sibling Relationships and Psychological Distress

The significant positive correlation found between negative sibling relationships and levels of depression and psychological distress means that the more negative the sibling relationship, the higher the levels of depression and psychological distress among both the control and the study groups. These findings are strengthened by studies showing that during adolescence, good sibling relationships are associated with better social skills and greater self-confidence, on one hand, and low levels of isolation, depression, and delinquency, on the other (Stocker, Burwell, & Briggs, 2002; Yeh & Lempers, 2004; Zabala, Macdonald, & Treasure, 2009). Blessing (2007) found that adolescents with EDs are socially isolated, engage in little social activity with their peers, and lack close friends. She suggested that this is related to troubled relationships with their healthy sisters, which involve jealousy, lack of trust and shame, and make it difficult for these girls to sustain meaningful social relationships with their peer group.

In addition, the current study results show that among the sisters of young females with EDs, the existence of a negative relationship may overpower the effects of a positive relationship. A possible explanation for these findings is that the influence and internalization of negative interpersonal experiences is more significant than for positive interpersonal experiences (Bruce, Dolan, & Phillips-Grant, 2000; Howe, 2000). Another possible explanation draws on Antonovsky’s (1994) claim that emotional closeness is one of the basic experiences contributing to the development of a high sense of coherence. Thus, when sibling relationships are closer and based on reciprocity and love, then a better infrastructure exists for developing a higher sense of coherence. Therefore, it can be assumed that when the sibling relationship is negative, it may be more difficult to develop a high sense of coherence and good psychological health.

Depression

The findings regarding a higher level of depression among the sisters of young females with EDs as compared with those without EDs is in keeping with the findings of previous studies that focused on the siblings of sick or disabled children (Lobato, Barbour, Hall, & Miller, 1987). It is possible that in the case of EDs, the family members have higher levels of depression and psychological distress than in families with other illnesses due to a high level of psychiatric comorbidity, in particular depression (Karwautz et al., 2002).

Sense of Coherence and Psychological Distress

To the best of our knowledge, no studies have been conducted to date on the sense of coherence among siblings in general and among females with EDs in particular. As hypothesized, significant correlations were found in the current study between sense of coherence, psychological distress, and depression among the sisters of young females with and without EDs. Thus, the lower the levels of depression and psychological distress among the participants in both groups, the higher their sense of coherence. It should be noted that this correlation was found to be stronger among the sisters of young females with EDs.

These results support Antonovsky’s (1993) findings that a positive association exists between a high sense of coherence and both mental and physical health, with sense of coherence used as a coping resource. Therefore, individuals with a high sense of coherence have a lower tendency to perceive various stress situations as threatening and cause for anxiety, believing instead in their ability to cope effectively with these situations (Antonovsky, 1979, Antonovsky & Sagy, 1986; Eriksson, Lindström, & Lilja, 2007). Other studies show that people with a low sense of coherence tend to express greater psychological distress, depression, and morbidity and thus to use an avoidance coping pattern (Amirkhan & Greaves, 2003; Benassi, Sweeney, & Dufour, 1988). Hence, it can be assumed that the sisters of young females with EDs who themselves have a low sense of coherence will be more vulnerable to feelings of helplessness, depression, and psychological distress.

Additionally, the current findings provide support for those of previous studies described in the literature indicating that sense of coherence has a significant negative correlation with anxiety, depression, subjective perception of stress, somatic complaints, physical symptoms, and high-risk behaviors (Antonovsky, 1993; Engelhard, van den Hout, & Vlaeyen, 2003; Korotkov, 1998; McSherry & Holm, 1994; Suominen, Helenius, Blomberg, Uutela, & Koskenvuo, 2001).

The Research Model

A research model emerged from the study findings, showing that the variables of belonging to one of the two groups (sisters with or without EDs), sense of coherence, and quality of the sibling relationship were significant predictors of the healthy sisters’ level of depression. These predictors explained 51% of the model. In addition, in both groups, it was found that the higher the sense of coherence, the lower the level of depression, and that the more negative the sibling relationship, the higher the depression level. Given this research model, it is suggested that when one sister has an ED, a negative sibling relationship can influence the psychological health of the sister without the ED, and that the level of depression has a determining role in the correlation between the two. However, a high sense of coherence significantly reduced the influence of ED on the level of depression of the healthy sister.

Study Limitations

The present study has several methodological limitations. The first is the small sample size of 60 participants, which made it difficult to perform complex statistical analyses and therefore limits the significance of the findings. The second limitation is the lack of uniformity in the severity of the sister’s illness, with some of the sisters requiring hospitalization whereas others received treatment in outpatient clinics. The third limitation is the variance in the birth order, as uniform sampling on the birth order of the sisters without ED was not performed. The variance posed by these last two limitations might have influenced the findings.

Theoretical and Practical Implications

The study contributes to theory, research, and practice regarding the significance of sibling relationships in general and negative sibling relationships in particular, as well as the sense of coherence and psychological state among the sisters of young females with EDs. Additionally, the study findings contribute to the theoretical and research literature about the family as a system, especially the sibling subsystem. The study may also contribute to the existing body of knowledge on EDs and the family in terms of the implications of the illness for siblings in general and for sisters in particular.

Raising professional awareness about the illness and its implications for the sisters of young females with EDs may help in identifying groups at risk and providing support for them accordingly (Treasure et al., 2008). From a clinical perspective, the contribution of this study is in drawing attention to the importance of involving the sisters in treatment, recruiting their support, strengthening the relationship between the sisters, and providing guidance and support for parents on this issue. An appropriate intervention program should be developed to evaluate the strengths within the family in general and the coping resources of the healthy sisters, in particular. Moreover, a therapeutic program should be designed to strengthen those coping resources and provide the healthy sisters with optimal assistance. It is extremely important to inform them about the illness and to involve them as much as possible in their sister’s treatment through individual and group counseling (Treasure et al., 2008).

In addition, throughout the therapeutic process, attention should be paid to the influence of negative sibling relationships and to strengthening the relationship between the sisters, while preventing criticism and negative remarks between them. It is recommended that the therapeutic process place the sibling dyad in the center, raising issues related to jealousy, competitiveness, guilt, hostility, and avoidance. By dealing with these issues in the difficult process of coping with the illness, the supportive strength of the sibling subsystem may be restored, helping the healthy sister to prevent psychological difficulties, on one hand, and enabling her to assist in her sister’s recovery process, on the other.

In conclusion, developing an intervention program that includes instrumental information and psychological processing will enable the healthy sister to maintain a high sense of coherence and to improve her relationship with the sister who has an ED. The hope is that in this manner, the sister without the ED will be able to preserve her own psychological health and even improve the psychological state of her sick sister.

Conclusions

The study findings revealed significant differences between the sisters in the study group and the control group. Higher levels of depression and negative sibling relationships were found among the sisters in the study group than among those in the control group. In addition, a significant correlation was found between negative sibling relationships and depression; in other words, the more negative the sibling relationship, the higher the level of depression. A significant negative correlation was also found between the sense of coherence and depression, meaning that the greater the sense of coherence, the lower the level of depression. Moreover, a negative relationship with the sister who had an ED was found to play a significant role in the depression level of the sister without the ED.

Footnotes

Acknowledgements

Special thanks to Professor Yoav Lavee for his advice on the statistics, which made a great contribution to the article.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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