The Mediating Role of Depression Between Early Maladaptive Schema and Pain: A Structural Equation Modelling


 Background: Individuals with chronic pain frequently display comorbid depression. Depression and chronic pain may be related to childhood maltreatment and early distress. Early maladaptive schemas (EMSs) designed to assess early distress. EMSs are at the core of personality pathology and psychological distress.Objective: The main objective of this study was to test the hypothesis that depression mediates the relationship between EMSs and pain.Methods: One hundred chronic pain patients completed Young’s Schema Questionnaire, McGill Pain Questionnaire and depression subscale of Hospital Anxiety and Depression Scale. Results: We estimated two structural models; second model fitted the clinical sample well (chi2= 19.2; p= .31). In this model a latent variable (general maladaptive schema) was explored is directly associated with depression (β=0.39; p<0.01); Also depression is associated with the pain (β= -.57; p<0.01); General maladaptive schema had an indirect effect on pain that was mediated by depression (β= -.35; p<0.01). Conclusions: The results of the study suggested that early emotional maltreatment plays an important role in depression and pain in chronic pain patients. The model can help to adequate and establish targets for the psychological treatments included in multidisciplinary programs for this disorder.

trauma (17,18). Childhood sexual, physical and emotional abuse and psychological and social adversities of childhood have been shown in numerous studies to be associated with somatic complaints and chronic pain in adulthood (19,20,21,22) and also with depressiveness (23,24,25,26,27). Abusive or neglectful childhood experiences are reported to be associated with an increased danger of experiencing chronic pain in adulthood (28). The association of chronic pain and emotional maltreatment alone has been less studied.
Young's schema-focused therapy is based on negative core beliefs or early maladaptive schemas (EMSs) which refer to dysfunctional cognitive frameworks for viewing the self and others that develop primarily in response to adverse childhood events and are subsequently elaborated throughout an individual's life. More speci cally, EMSs develop when universal psychological core needs (e.g., autonomy, support, understanding, secure attachment and freedom to express valid needs and emotions) are not met. EMSs act on the deepest level of cognition, usually outside of awareness, and make the individual psychologically vulnerable to develop depression, anxiety, psychosomatic disorders such as chronic pain and dysfunctional relationships (29).
Young, Klosko, and Weishaar (30) recognized 18 EMSs that persons can develop and maintain. These 18 EMSs can be categorized into ve different domains. Schema domains include disconnection and rejection, impaired autonomy and performance, impaired limits, other directedness and over vigilanceinhibition. Each domain represents one important part of the core needs of the child. Many EMSs like mistrust/abuse, abandonment/instability or emotional deprivation re ect purely early emotional maltreatment, such as abandonment and neglect.
Researches of both clinical and university samples have provided evidence that EMSs in all ve domains are associated with higher current levels of depressive symptoms (31,32,33,34 ). Most notably, there is substantial evidence that dysfunctional attitudes, which are another form of cognitive vulnerability (35,36,37) and interpersonal vulnerability factors (38,39) predict depressive symptoms when activated by stressful life events. Zautra et al. (40) found consistent evidence that a history of depression increases risk of pain among rheumatoid patients.
Also they found current depressive symptoms were also associated with greater pain in rheumatoid arthritis patients. Saariaho , Saariaho , Karila , and Joukamaa (41) showed that from a total of 271 chronic pain patients 158 scored one or more early maladaptive schema as meaningful. The patients with meaningful EMSs had significantly higher pain intensity.
Despite the association between chronic pain, early maladaptive schema factor and depression and their similar risk factors in childhood, the quality of the association between them is not de nite. These EMSs show extensively underlying psychic patterns and serve as a good opportunity to nd covert processes and psychic shapes.

Objective
With regard to considering the important role of EMSs in pain and depression in chronic pain patients and lack of research in this area, the purpose of this study is 1) to examine the presence of early maladaptive schemas in chronic pain patient sample and 2) to ascertain how pain, early maladaptive schema factors and depressiveness are related together in the chronic pain patient and 3) to test bio-psycho-social model of pain within a chronic pain patient sample.

Participants and procedures
A cross-sectional study was used to examine the association between pain, depression and early maladaptive schema and to identify predictors of pain in chronic pain patients. The protocol of the study was approved by the "Regional bioethics committee". According to accepted statistic criteria a sample size between 100 and 200 subjects is considered adequate for studies involving parsimonious models to be estimated by structural equations (47). The sample composed of 100 patients with chronic pain. These patients were recruited from an outpatient chronic pain clinic a liated with Lorestan University of Medical Sciences. Of the initial sample of 115 patients, 15 (13.04%) were excluded because of incomplete data. The nal sample consisted of 100 patients, including 72 (72%) females with a mean age of 45.46±12.67 years and 28 (28%) males with a mean age of 40.68±13.99 years. The mean length of total education was 13.07± 2.72 years (range 9-18 years). The mean length of duration of pain in total sample was 5.67± 5.74 years. Men and women did not differ in age, duration of pain and education.
Inclusion criteria were: 1) receiving the diagnosis of chronic pain by a neurologist and spine specialist 2) age 18-70 years old 3) being able to write and read 4) willingness to participate in the study. Patients were excluded if: 1) had dementia and mental retardation 2) were unable to write and read or were not agree to be participated in study.
The procedure was as follow: First patients were visited by a neurologist and spine specialist and the diagnosis based on experimental criteria was established. Then for those who ful lled the inclusion criteria, the aim and the process of the study along with con dentiality of the gathered information were described. If the patient agreed to continue and was orally consent to participate in the study, then they were asked to complete 4 questionnaires including socio-demographic data form, depression subscale of Hospital Anxiety and Depression Scale (HADS), third edition of Young's Schema Questionnaire(YSQ-SF3) and McGill Pain Questionnaire (MPQ). Weishaar (30). The original scale has 18 subscales grouped into 5 schema domains as follows: disconnection and rejection (schemas of emotional deprivation, abandonment, mistrust/abuse, social isolation, and defectiveness), impaired autonomy and performance (schemas of failure, dependence, vulnerability, and enmeshment/ undeveloped self), impaired limits (schemas of entitlement and insu cient self-control), other directedness (schemas of subjugation, approval-seeking, and selfsacri ce) and Over-vigilance and inhibition (schemas of emotional inhibition, unrelenting standards, negativity/pessimism, and punitiveness). The questionnaire consists of 90 self-report items that are rated on a six-point Likert-type scale (1 = entirely untrue of me, 6 = describes me perfectly). As each subscale consists of ve items, the score obtained on the subscales varies between 5 and 30.
Soygüt , Karaosmanoglu , and Cakir (48)has shown good levels of validity and Reliability. The reliability and validity of the YSQ-SF extended in Iranian language has been (49). In our study the Cronbach's alpha coe cients for the YSQ-SF3 subscales range between .74 and .90.

Hospital Anxiety and Depression Scale (HADS)
HADS is a self-report scale which was developed for detecting symptoms of anxiety and depression in non-psychiatric patients from a medical outpatient unit. It contains two seven-item subscales: one for depression and one for anxiety, with a score ranging from 0 to 21. Every item has a choice of 4 xed response statements (weighted 0-3). A score of 8 to 10 points indicates borderline signi cance for either scale, but less than 8 points is insigni cant. A cut-off score of 7 was used because investigations have shown that this is optimal for detecting psychiatric morbidity (50). The reliability and validity of the HADS to detect mood disorders has been recognized (51). In general the Iranian version of the HADS can be considered reliable and valid. Cronbach's alpha coe cient (to test reliability) has been found to be 0.86 for the HADS depression sub-scale and 0.78 for the HADS anxiety sub-scale (52). In the present study, the Cronbach's alpha coe cient for the HADS depression sub-scale was 0.84.

McGill
Pain Questionnaire (MPQ) is a self-reporting measure of pain used for patients with a number of diagnoses. It assesses both quality and intensity of pain patients. The MPQ is composed of 78 words, of which respondents choose those that best describe their experience of pain. 7 words are selected from the following categories: dimension 1 to 10 (pain Sensory), three words; dimensions 11 to 15 (pain affective), dimension 16 (pain Evaluative) one word, and dimension 17 to 20 (pain miscellaneous) one word. Scores are formulated by summing values associated with each word; scores range from 0 (no pain) to 78 (severe pain). Qualitative differences in pain may be re ected in respondent's word choice (53).

Statistical Analysis
Structural equation modelling (SME) were conducted using AMOS-18. These models permit to include variables that are correlated with, and can be used to predict other variables. Parameter estimates, including factor loadings, indirect and total associations, and path coe cients for direct, and residual error variance terms for criterion variables, were examined for statistical signi cance. The following criteria were used as indexes of acceptable model t: Analysis process started with a model de ned from theoretical approach (Figure 1). This model is adopted from the stories of chronic pain patients. The basic structure of this model is similar to the study by Saariaho et al., (41). A SEM of latent variable was developed with depressiveness as a mediator between latent variable and pain. SEM required selection of beginning and endpoints in the cyclical model and pain was designed as the endpoint for the model. As shown in Fig. 1, the latent construct General Maladaptive Schema (GMS) was speci ed by ve schema domains: disconnection and rejection, impaired autonomy and performance, impaired limits, other-directedness, over vigilance and inhibition.
Amos software path analysis was conducted to test the model which showed the direct and indirect effects of GMS on pain with the mediation of depressiveness.

Results
Means, standard deviations, and scale reliabilities (Cronbach's Alpha) for the SQ-SF, pain and depression subscale of HADS are shown in Table1. In all cases these alpha levels were well above 0.70 and showed good internal consistencies. The average depression score indicate moderate depressive symptoms. In total chronic pain patients the scores for Self-Sacri ce (20.  Table 2. Correlations between the various schemas domains and depression were signi cant and ranged from 0.42 to 0.72.  Fig.2, all of which them are signi cant. As can be seen from Fig.2, GMS is directly associated with depression (β=0.39; p<0.01); explained variance for depression was 36%. Also depression is negative associated with the pain (β= -.57; p<0.01); and explain 32% of its variance. GMS had an indirect effect on pain that was mediated by depression (β= -.35; p<0.01). Table 3 contains both invariant and standardized structural model parameters for chronic pain patients from alternative model.

Discussion
Accumulating evidence indicates that individuals with chronic pain have more psychological compliance than other populations. The aim of this study was to investigate the relationship between EMSs, depression and pain in chronic pain patients.
Self-sacri ce was the highest mean scored schema in chronic pain patients. This nding is consistent with previous study (46) and emotional deprivation schema was second highest mean scored schema in chronic pain patients in this study. Self-sacri ce schema is a belief that one should focus on others' needs rather than one's own (30). Chronic pain patients with self-sacri ce schema had been work very long hours since childhood which had caused them to suffer pain and prevented them from recovering from pain and they hoped to be in less pain to return to the same work (46). They frequently assumed a caregiver's role and hid their pain. Finally they become pain-exhausted, because only the maximum pain is able to stop them.
Young, Klosko , and Weishaar (30) reported that the patient with self-sacri ce schema almost always has emotional deprivation schema. Emotional deprivation schema is the belief that one's primary emotional needs will never be met by others. Emotional deprivation schema is a common schema in psychosomatic disorders such as chronic pain. The patients with emotional deprivation schema do not express their feelings. Therefore patients with limited emotional awareness and verbalization ability may describe the physiological aspects of emotions in somatic terms, such as pain severity.
The third highest mean scored schema in this study was unrelenting standards/hyper criticalness schema. People with this schema emphasize excessively on attaining very high internalized standards of behaviors or performances. They strive to reach these high standards to avoid criticism. Unrelenting standards/hyper criticalness schema provokes pain problem, as the pain patients were extremely careful and conscientious in their work and ignored their bodies' sensations or need for rehabilitation.
The ndings showed that men compared to women had signi cantly higher mean scores in the entitlement/ grandiosity, approval seeking and unrelenting standards/hyper criticalness schemas. These schemas labeled were encumbered pattern (46). Chronic pain patient with these schemas is selfdemanding, seeks approval almost resignedly. They strive frenetically for achievement, approval or perfection. These patients have overactive life-style. Such a life-style can be a predisposing, initiating and perpetuating factor for chronic pain and it strongly resembles the content of encumbered pattern (54,55,56,46 ).
In line with Young theory, the study found evidence that maladaptive schemas domains were signi cantly associated with depressive symptoms (30). Such results are consistent with a number of previous studies (23, 42,57,58,59). The results showed that GMS predicted depressiveness and depressiveness predicted pain. Also GMS had direct effects on depressiveness but GMS had not direct effect on pain. GMS had an indirect effect on pain that was mediated by depressiveness. From the theoretical point of view the data support the view that early adversities such as childhood neglect, emotional abuse and early emotional maltreatment predispose chronic pain patients to depression.
Childhood emotional maltreatment (i.e., neglect or verbal hostility) will be preferentially associated with negative schemas with themes of loss and worthlessness (e.g., Emotional Deprivation, Dependency, Social Isolation, Failure, Vulnerability, Subjugation, and Self-Sacri ce) that mediate high levels of anhedonic symptomatology (60).The data suggests a salient role of early emotional trauma in the progression of depression in chronic pain patients such as chronic pain. Therefore it can be concluded different EMSs mediate the relation between childhood adversity and later depression.
Also the results showed that depressiveness predicts pain symptoms. The estimate support antecedent theory (depression precedes pain) in the chronic pain patient (61) (Currie & Wang, 2005).This nding is consistent with Zautra et al. (40). The reason for this nding is that depressed patients have reduced pain perception thresholds and tolerances. Also another explanation for this nding, referring to the diathesisstress model (62), is that chronic pain patients have psycho-social diathesis (early maladaptive schema factors) and the stress of chronic pain triggers the depression which in turn compounds disability (9,63) and de ciency in the descending inhibitory system of pain (64,65). According to the model, GMS could not directly predict pain. This nding is consistent with Saariaho et al., (41). They showed that pain intensity was not predicted by any of the schema factor. One explanation for this nding may be that the pain and schema factor are not parallel processes. Another reason for this nding could be that with increasing age among patients with chronic pain, some EMSs predicted pain disability and pain intensity, but since in our study the range of age varied, activated maladaptive schema of the subjects were different thus GMS could not predict pain. One limitation of the current study is the use of self-report questionnaires for the assessment of the EMSs, pain and depression, which may in uence the accuracy of these reports. As an alternative to self-report questionnaires, future researches may use projective tests or physiological indicators of information processing in the evaluation of EMSs (65,66) or a history of life approach as utilized by Abela, Auerbach, Sarin,& Lakdawalla (67). In addition, this study was cross-sectional and only prospective analyses will give an exhaustive picture of the causal relationships between EMSs, depression and pain.

Conclusions
The ndings of the present study are indicative of a relationship between schema-level dysfunction, depression and pain. Prospective and experimental researches were required to further clarify the nature of this relationship so that more conclusive statements can be made regarding the potential causal and/or maintenance role of maladaptive schemata in triggering pain problems and depression. For instance, of bene t would be prospective research investigating whether a higher level of maladaptive schemata predicts more pain disability, pain severity and depression. Such study should address the potential role of general schema disturbance as well as speci c schemata and investigate the multiple pathways through which schemata may have a negative impact on pain control behaviors. Ultimately, further study into the role of EMS in pain may provide a rationale for the implementation of schemabased interventions as a component in the treatment of chronic pain individuals.