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Aim: The goal of the study was to investigate the correlations among parental bonding patterns, eating disorders (ED) and self-injurious behavior (SIB).
Methods: The subjects were 80 patients with ED who were divided into two groups based on those that had (n = 25) and had not engaged in SIB at least once in the last month. The patients and 120 healthy control subjects were evaluated using the Eating Disorder Inventory and the Parental Bonding Instrument.
Results: On the Parental Bonding Instrument, the ED + SIB group showed significantly lower paternal care compared with the ED/no SIB and control groups. On the Eating Disorder Inventory, the ED + SIB group showed higher body dissatisfaction, and increased maturity fear compared with the other two groups. The total scores and perfectionism and interoceptive awareness differed significantly among the three groups.
Conclusion: ED + SIB patients had a more severe ED pathology than ED/no SIB patients, and also felt that they had received low paternal care during childhood. Therefore, paternal care may be linked to severe ED pathology.
EARLY ETIOLOGICAL INVESTIGATIONS suggested that the family played an important role in the development of eating disorders (ED), including anorexia nervosa (AN) and bulimia nervosa (BN). These studies focused on overprotection from mothers and indifference of fathers. Evaluations using the Parental Bonding Instrument (PBI) have produced uneven results, with patients with binge eating purging type AN having less care and greater overprotection from both parents compared to those with restricting type AN and normal controls;1 BN patients having greater maternal overprotection and AN patients having higher paternal overprotection;2 and binge eating patients having less care from both parents compared to AN patients, with no significant difference in overprotection.3
In the 1980s, an association between self-injurious behavior (SIB) and ED was noted in several studies.4–6 Svirko and Hawton found that the incidence of SIB in ED ranged from 25.4% to 55.2%.7 These patients are generally understood to be difficult to treat and to have more complicated family environments. In an early review, Simpson and Porter noted that SIB patients more often experience emotional distancing from parents and inconsistent parental warmth.8 Carroll et al. suggested that SIB patients are more likely to come from families characterized by divorce, neglect, or parental deprivation,9 and recent studies have demonstrated a close association between SIB and childhood sexual or physical abuse.10 Claes et al. found that the family environment of ED patients with SIB was less cohesive, expressive and socially orientated, and more conflictual and disorganized compared to that of ED patients without SIB.11
Previous studies of ED with SIB have had several limitations, one of which is the use of a system based on operational diagnoses. Some authors have proposed that SIB is an independent clinical entity that occurs in the context of ED,4,12 while others have suggested that self-injurious and abnormal eating behaviors are only partial symptoms in patients with borderline personality disorder.13 In recent years, the significance of diagnostic subtyping of ED according to DSM criteria has been questioned. Some studies have shown that patients are more distinctively classified if personality features,14 temperament, and character15 are taken into account. Therefore, placement of ED patients on an impulsivity–compulsivity spectrum has been proposed, especially as high rates of SIB have been described in these patients.16,17
Another problem is the ambiguous definition of self-injury. Self-injurious behavior is often synonymously used with terms such as self-mutilation or self-harm. The concept of self-mutilation refers to more severe forms of self-harm, such as eye enucleation or castration. Self-harm is a more general term that is often used to refer to suicide attempts and may also include indirect methods of self-damage, such as binge eating, alcohol or drug abuse, or overdose. Farverow named obesity, smoking and substance abuse as ‘indirect methods of self-mutilating behavior’, and suggested that these types of behavior are greatly influenced by unconscious factors, while SIB refers to behavior involving direct and deliberate damage of one's own body.18 Thus, the ‘official’ definition of terms shown above is clear, however many studies use them in an inaccurate manner. Therefore, it seems that these kinds of behavior should not be discussed collectively.
To our knowledge, parental bonding patterns in patients with ED and SIB have not been examined. After consideration of the above issues, we investigated the clinical features of ED with SIB in Japanese patients from the perspective of parental bonding. We defined SIB as the ‘direct and deliberate damage of one's own body surface without suicidal intent’.19 Claes et al. developed the Self-Injury Questionnaire – Treatment Related (SIQ-TR) to assess active SIB in female ED patients, with a focus on the causes and functional consequences of SIB.20 In the SIQ-TR, SIB is limited to that occurring within the last month, with definition of five types of SIB that are frequently reported in ED: scratching, bruising, cutting, burning, and biting. Each subject was also free to list a type of self-injury (if any) that was not included among the five types. We adopted this definition of SIB in the current study.
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EDI and PBI scores for the ED + SIB, ED/no SIB and control groups are shown in Table 4. On the EDI, ‘Total Score’ (P < 0.001), ‘Perfectionism’ (P < 0.001) and ‘Interoceptive Awareness’ (P < 0.001) differed among the three groups. Bonferroni post-hoc tests showed that the ‘Total Score’ was significantly higher for the ED + SIB group compared to the ED/no SIB (P < 0.005) and control (P < 0.001) groups, and for the ED/no SIB group compared to the control group (P < 0.005). The ‘Perfectionism’ score was significantly higher for the ED + SIB group compared to the ED/no SIB (P < 0.05) and control (P < 0.001) groups, and for the ED/no SIB group compared to the control group (P < 0.001). The ‘Interoceptive Awareness’ score was significantly higher for the ED + SIB group compared to the ED/no SIB (P < 0.01) and control (P < 0.001) groups, and for the ED/no SIB group compared to the control group (P < 0.001). The ‘Body Dissatisfaction’ (P < 0.01) and ‘Maturity Fear’ (P < 0.05) scores also differed among the three groups. Bonferroni post-hoc tests showed that the ‘Body Dissatisfaction’ score was significantly higher in the ED + SIB group compared to the ED/no SIB (P < 0.01) and control (P < 0.05) groups. The ‘Maturity Fear’ score was significantly higher in the ED + SIB group compared to the ED/no SIB (P < 0.05) and control (P < 0.05) groups, but did not differ between the ED/no SIB and control groups.
Table 4. Comparisons of scores on the EDI and PBI
| ||ED + SIB (A) n = 25||ED/no SIB (B) n = 55||Control (C) n = 120||F||d.f.||P||Post-hoc tests|
|EDI|| || || || || || || |
| Total score||113.9 ± 36.8||85.6 ± 36.9||63.5 ± 35.9||22.7||2,197||<0.001||A > B > C|
| Perfectionism||9.7 ± 4.1||7.0 ± 4.6||4.3 ± 4.1||20.6||2,197||<0.001||A > B > C|
| Interoceptive awareness||19.8 ± 8.3||14.1 ± 7.7||7.7 ± 7.7||31||2,197||<0.001||A > B > C|
| Body dissatisfaction||19.2 ± 7.5||14.1 ± 6.3||15.1 ± 6.8||5.1||2,197||<0.001||A > B,C|
| Maturity fear||11.0 ± 5.3||7.7 ± 5.4||7.7 ± 5.2||4.4||2,197||<0.05||A > B,C|
|PBI|| || || || || || || |
| Paternal care||17.6 ± 9.2||22.9 ± 9.0||23.7 ± 8.4||5.4||2,195||<0.005||A < B,C|
| Paternal protection||14.8 ± 8.5||11.4 ± 7.9||12.7 ± 7.1||1.7||2,195||NS||NS|
| Maternal care||24.4 ± 8.2||24.0 ± 10.9||29.0 ± 6.8||8.2||2,197||<0.001||A,B < C|
| Maternal protection||16.2 ± 9.9||12.5 ± 8.6||11.3 ± 7.0||3.9||2,197||NS||NS|
On the PBI, the ‘Paternal Care’ (P < 0.005) and ‘Maternal Care’ (P < 0.001) scores differed among the three groups. A Bonferroni post-hoc test showed that the ‘Paternal Care’ score was significantly lower in the ED + SIB group compared to the ED/no SIB (P < 0.05) and control (P < 0.005) group, but did not differ between the ED/no SIB and control groups. Dunnett's T3 test showed that the ‘Maternal Care’ score was significantly higher in the control group compared to the ED + SIB (P < 0.05) and ED/no SIB (P < 0.001) groups, but did not differ between the ED + SIB and ED/no SIB groups.
Results for the PBI quadrants (Fig. 1) are shown in Table 5. A Fisher's exact test indicated a difference between the ED + SIB and ED/no SIB groups for paternal bonding (P < 0.05), but not for maternal bonding.
Table 5. Scores for quadrants on the Parental Bonding Instrument (PBI)
|Parent||PBI quadrant||ED + SIB||ED/no SIB|
|Father†||I Affectionless control||13||54.2%||10||18.5%|
|II Affectionate constraint||3||12.5%||8||14.8%|
|III Neglectful parenting||6||25.0%||19||35.2%|
|IV Optimal parenting||2||8.3%||17||31.5%|
|Mother||I Affectionless control||11||44.0%||16||29.1%|
|II Affectionate constraint||3||12.0%||5||9.1%|
|III Neglectful parenting||5||20.0%||12||21.8%|
|IV Optimal parenting||6||24.0%||22||40.0%|
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The results of the study indicated that patients with ED and SIB had a more severe ED pathology than those with ED without SIB. This result is similar to the association of higher impulsivity with severity of ED symptoms found by Favaro.28 The EDI score for ineffectiveness in BN patients with multi-impulsive types of behavior (three or more) has been reported to be higher than that in BN patients with two or fewer impulsive behavior types.29 Ross et al. also found that high-school students who engage in non-suicidal self-injury (NSSI) display significantly more eating pathologies than their non-NSSI peers.30
The results of this study differ from other studies focusing on recent self-injuries in the last month. On the EDI, body dissatisfaction and maturity fear were significantly higher in these patients than in ED patients without SIB and controls. As far as we are aware, the EDI has not been used previously to compare ED with and without SIB. It is possible that our results indicate that patients with ED and SIB loathe their body and reject becoming adults through self-injury. These may be some aspects of the functions of SIB. Patients with ED and SIB, and other kinds of psychiatric patients with SIB, are understood not to care about their bodies and to replace negative affection with psychical pain. Our results are consistent with this view. The ED + SIB and ED/no SIB groups both had lower interoceptive awareness, but this was significantly lower in the ED + SIB group. This low interoceptive awareness may contribute to other psychopathology, such as a twilight or numb state. This may explain the different degrees of the ‘painless’ state shown in Table 3. The high perfectionism in patients with ED and SIB also suggests that compulsivity might also be included in SIB. This result is consistent with previous findings that patients with BN and SIB are significantly more likely to have comorbid obsessive–compulsive disorder compared to BN patients without SIB.31
The PBI score showed that patients with ED and SIB perceived that they received low paternal care, with more than half of these patients feeling that their father exhibited ‘Affectionless control’. We also investigated the difference in parental care scores between restricting type AN patients and others because of the difference in the number of patients with restricting type AN who did and did not engage in SIB. However, there was no difference in parental care scores between these subgroups, which indicates that differences in ED subtypes are unlikely to influence the paternal care score. It is also of note that maternal care scores for ED patients with and without SIB were lower than for controls, whereas the paternal care score did not differ significantly between ED patients without SIB and controls. This suggests that ED patients without SIB mainly have conflict with their mother, whereas ED patients with SIB also have conflict with their father. These results support the hypothesis that the family environment of ED patients with SIB is more complicated than that of ED patients without SIB.
ED studies have focused on family or parental bonding as the cause of the disease, but the role of the family in treatment is more important. Our results indicate the need for participation of a patient's father in this treatment. ED patients are generally thought to have conflict with their mother, with their father needing to contain the complicated mother–child relationship or promote separation when they are deadlocked.32 In treatment, ED patients tend to focus on food or weight. It is often hard to make progress with the treatment, as the treatment relationship is likely to be superficial and patients readily drop out. Our results suggest that development of insights into the paternal relationship may provide effective treatment for patients with ED and SIB. We suggest that therapy for patients with ED should vary depending on the presence or absence of SIB, and that further assessment of this therapy is required in patients with active SIB.
This is the first study in Japan to examine ED patients with SIB. Previous Japanese studies have examined psychological traits in patients with impulsive behavior or in those who made suicide attempts,29,33 but not in patients with ED and SIB. Furthermore, most previous Japanese studies on SIB have had important limitations. First, the timeframe of the SIB has not been established, as the studies have used questions such as ‘Have you ever committed self-harm behavior?’ The PBI score also changes from before to after treatment;1,34 therefore, assessment of the score for ED patients with recent SIB is required. A second problem is the ambiguity of the definition of SIB. Since previous research has shown that SIB differs from other general self-harm or suicide attempts,18,20 we specified both the timing and manner of the SIB in this study.
The current study also has several important limitations. First, we were unable to investigate ED subtypes and the SIB type (impulsive or compulsive) because of the small number of subjects. In BN patients, Favaro and Santonasstaso17 classified SIB into ‘impulsive SIB’, which included skin cutting, burning, suicide attempts, substance/alcohol abuse, and laxative/diuretics abuse; and ‘compulsive SIB’, which included hair pulling, severe nail biting, and self-induced vomiting. Impulsive SIB is repetitive but egodystonic, with patients trying to resist the urge for the behavior. On the other hand, compulsive SIB is more episodic, but gratifying and egosyntonic, and is often triggered by external events and involves little resistance on the part of the patient. The difference between the two types of SIB depends on personality characteristics. Furthermore, Maggini suggested that personality characteristics in ED with SIB differed for the two types of SIB.35 Likewise, the PBI is linked to the psychological defense style in ED.36 Therefore, perception of parental bonding may also differ for the two types of SIB. Thus, the possible influence of ED subtypes on SIB remains to be examined in a further study in a larger population that is categorized based on ED subtype and the type of SIB. Second, we did not consider comorbid psychiatric states in this study. A previous study showed that depression is not correlated with PBI score,37 but further research on the correlation between comorbid psychiatric states and PBI scores is required.