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Self-Worth and Self-Knowledge in Iranian Patients Seeking Cosmetic Surgery: A Comparative Study

Prior research has reported a psychological impairment in patients seeking cosmetic surgery. However, the role of other variables such as contingencies of self-worth and self-knowledge has been ignored. Hence, the aim of this study was to examine new psychological structures, contingencies of self-worth, and self-knowledge among patients seeking cosmetic surgery. Eighty patients (47 female and 33 male; mean age = 28.98, SD = 8.32; 40 seeking cosmetic surgery and 40 seeking surgical treatment) were randomly recruited from the Shahid Motahhari clinic in Shiraz, Iran. The patients completed the Contingencies of Self-Worth Scale, Integrative Self-Knowledge Scale, Subjective Vitality Scale, and Depression Anxiety Stress Scale-21. The results showed that, compared to the surgical treatment group, self-worth in patients seeking cosmetic surgery was found to depend on their appearance and the approval of others. Further, the self-knowledge in patients seeking cosmetic surgery was lower than that of patients seeking surgical treatment. In addition, there were no significant differences between the two groups in vitality, depression, anxiety, and stress. It can be concluded that patients seeking cosmetic surgery have lower self-knowledge and their self-esteem depends on their appearance and the approval of others.


Introduction
According to statistical reports published by the American Society of Plastic Surgeons (2012), 14.6 million cosmetic surgeries were conducted in the United States in 2012, of which 39% had been done over the previous five years. Further, in 2015, Americans spent more than $13.5 billion on cosmetic surgeries (International Society of Aesthetic Plastic Surgery, 2015). In 2013, the International Society of Aesthetic Plastic Surgery reported that Iran was among the top 10 countries in the world conducting cosmetic surgeries. However, despite this increase, there has been a lack of research into why there has been an increase in seeking cosmetic surgery in Iran, despite the financial and personal costs for both the individuals and their families .
The desire to undergo cosmetic surgery is linked to several psychopathological traits and sociological factors.
For example, research indicates that patients who undergo cosmetic surgery are more likely to have dysmorphic disorders, anxiety and depression symptoms, obsessivecompulsive disorder, phobias, different types of personality disorders, somatization disorders, thought disorders, sleep problems, and social anxiety (Collins et al., 2014; Creative Commons Non Commercial CC BY-NC: This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us. sagepub.com/en-us/nam/open-access-at-sage). Dakanalis et al., 2013;Khanjani et al., 2012;Meningaud et al., 2001;Mulkens et al., 2012;Sohrabi et al., 2011). In terms of sociological factors, research suggests that individuals seeking cosmetic surgery are more likely to have friends who have undergone cosmetic surgery, used media more, and had a higher family income (Eriksen & Goering, 2011). Further, research has reported that anxiety about aging and increased exposure to television were unique predictors for seeking cosmetic surgery. Media has been found to be a strong factor regarding attitudes about cosmetic surgery (Markey & Markey, 2010;Slevec & Tiggemann, 2010). Delinsky (2005) reported that the possibility of undergoing cosmetic surgery increases with a rise in the internalization of sociocultural attitudes about appearance. Maltby and Day (2011) indicated that an intense admiration of a celebrity can positively predict being a candidate for cosmetic surgery. In addition, research has shown that body dissatisfaction, the internalization of media messages, reports of physical-appearance teasing (Markey & Markey, 2009), media pressure, appearance conversations, and the internalization of thin ideals were correlated with women's interest in cosmetic surgery (Nerini et al., 2014).
Until now, most research has focused on the pathological factors (e.g., Collins et al., 2014) or psychological problems underlying the desire to undergo cosmetic surgery, but it has not yielded consistent results (Sarwer et al., 1998). Therefore, this study uses a non-pathological perspective to investigate the role of self-worth and self-knowledge in patients seeking cosmetic surgery.
Psychologists have long believed that self-esteem is a powerful force in people's lives. Contingent self-esteem refers to the time when people learn that their worth and lovability depend on achieving particular outcomes (Swann & Bosson, 2010). The contingencies of selfworth refer to areas in which success or failure correlates with high or low self-esteem. Therefore, while the need for high self-esteem guides most of our behaviors, it has a significant cost (Crocker, 2002). Using the Contingencies of Self-Worth Scale, Crocker et al. (2003) evaluated different sources of self-esteem among college students. These sources included academics, appearance, the approval of others, competition, family support, God's love, and virtue. These contingencies are organized into two distinct higher order factors: external and internal contingencies of self-worth (Crocker et al., 2003). The contingencies of self-worth theory suggests that the fundamental issue that predicts a certain behavior is not whether selfesteem is high or low, or conditional or unconditional; rather, it depends on certain areas upon which a person has grounded their worth. As a result, the contingency of self-worth provides self-regulation but still shows psychological vulnerability (Crocker, 2002).
People with a high contingency often try their best to succeed when there is a high chance of success. However, as a source of motivation, conditions of self-worth itself pose some significant drawbacks. When a task is difficult and failure is likely to happen, the conditions of self-worth result in feelings of stress, mental pressure, and a loss of intrinsic motivation. In these circumstances, people with high contingencies will probably withdraw from their goals and efforts. Furthermore, conditions of self-worth raise some problems for self-regulation following success (Crocker et al., 2006). The contingencies of self-worth make individuals invest more in areas that they feel are more valuable. According to Crocker et al. (2003), the contingencies of self-worth predict specific activities (how to spend your time). They found that contingencies of self-worth to appearance predicted sociability, whereas contingencies of self-worth to competition were negatively associated with sociability.
Some studies have shown that some, but not all, patients seeking cosmetic surgery generally have low self-esteem (Eriksen & Goering, 2011;Mulkens et al., 2012). Von Soest et al. (2009) found no differences in psychological processes (such as general self-esteem) between patients seeking cosmetic surgery and controls. Similarly, Ferraro et al. (2005) reported that general selfesteem does not motivate opting for cosmetic surgery. Unlike general self-esteem, it is likely that self-esteem that is dependent on specific areas can provide a better justification for why people tend to undergo cosmetic surgery. For example, Park et al. (2009) have shown that contingencies of self-worth to appearance have a significant positive correlation with the desire to undergo cosmetic surgery. In addition, the probability of undergoing cosmetic surgery in the future was found to increase with a rise in contingencies of self-worth to appearance but decrease with contingencies of selfworth to virtue (Delinsky, 2005).
Contemporary psychology has confirmed the importance of self-knowledge in psychotherapy (Ghorbani et al., 2003). Self-knowledge is a state of consciousness that assesses one's current psychological states and past experiences, and regulates one's thoughts and emotions in a healthy manner . It is a psychological process with three important features: integrity, adaptability, and mobility. Self-knowledge is an integrated process as it strives to make experiences and attitudes of self meaningful in synthesis or in combination. Self-knowledge is adaptable because it is a self-regulatory process which promotes the well-being of the self. It is also dynamic because the self must respond to changing circumstances repeatedly. Frequent changes in circumstances suggest that selfknowledge should consist of awareness about the present experience, which is also related to past experience (Ghorbani et al., 2003).
By definition, self-knowledge constitutes all aspects of recognition of the self. It includes self-awareness and stable representations of the self that evaluate an individual's ability to access current psychological states and process the content of current and past experiences, and separate them from each other, and assess an individual's cognitive processing of information related to his or her self (Shahmohammadi et al., 2007). This process is an adaptive and powerful effort of the self to understand experiences over time, which enables a person to adjust their thoughts and emotions through their potential understanding, recognition, and selection of optimal activities for the consequences (Asghari & Besharat, 2011).
Studies conducted on self-knowledge indicate that self-knowledge, in both Iranian and American samples, is a positive predictor of mental health and self-esteem (Ghorbani & Watson, 2005). Other studies also indicate that self-knowledge has a positive relationship with self-control, self-respect, self-esteem, self-compassion, life satisfaction, mindfulness, autonomy, competence, communication, internal religious orientation, compassion, psychological well-being, subjective vitality, self-awareness, and self-determination. Further, self-knowledge has been reported to have a negative correlation with anxiety, depression, perceived stress, impaired mental activities, rumination, repression, social anxiety, and extrinsic religious orientation (Ghorbani et al., 2008(Ghorbani et al., , 2011(Ghorbani et al., , 2012SabzeAra Langroodi et al., 2014).
Low self-knowledge has been associated with an increased tendency to undergo cosmetic surgery (Zarandi et al., 2012). Research suggests that individuals with limited knowledge of themselves are less flexible in controlling their thoughts and emotions; have personalities which are dependent on a negative evaluation of their appearance; are prone to problems related to their body image; and are more likely to seek cosmetic surgery (Naami & Salehi, 2016). However, people with high self-knowledge also have high introspection, which can sharpen their awareness of selfknowledge and thereby make their self-evaluation more accurate (Silvia & Gendolla, 2001). Moreover, individuals with high self-knowledge tend to have an integrated self and an ability to integrate their negative and positive beliefs (Showers & Kling, 1996). A more accurate, fact-based image of self and body is associated with high self-knowledge, and acts as a barrier against the desire to undergo cosmetic surgery. In fact, mindfulness or experiential self-knowledge creates a state in the individual which reduces the automatic arousal and productivity of cognitive distortions when the environment, the body, and the individual interact with each other. This, in turn, leads to a nonjudgmental view of body image and an emotional response which results in a reduction in the likelihood of malicious and impulsive behaviors, and an increased insight into the complexity of body-image experiences (Stewart, 2004) .
While, as shown in this literature review, a large number of studies emphasize the role of psychopathology, the media, and social pressure in patients undergoing cosmetic surgery, this study uses a nonpathological perspective to investigate the role of self-worth and self-knowledge in patients seeking cosmetic surgery. It tries to explain the role of selfknowledge and self-worth in people seeking cosmetic surgery, as potential psychological factors of superfluous needs in seeking cosmetic surgery. Therefore, we believe that this study can make a considerable contribution to the literature by considering the importance of self-knowledge and self-worth among people seeking cosmetic surgery. Knowing the differences among different populations will help us to understand them better and highlight individual differences among them. By knowing the differences, we can develop effective and suitable interventions. In this study, we used a comparative method to find out which contingences of self-worth are highlighted by people who are interested in obtaining cosmetic surgery, and whether or not they have low self-knowledge and high psychopathology compared to patients seeking surgical treatment. These differences can lead us to pay attention to these variables among individuals obtaining cosmetic surgery. This study aimed to examine contingencies of self-worth and self-knowledge structures in patients seeking cosmetic surgery in comparison with patients seeking surgical treatment (i.e., undergoing surgery to repair injuries). In addition, some studies have shown that patients seeking cosmetic and treatment surgery suffer from higher psychological distress and damage compared to the general population (Collins et al., 2014). However, taking into account the difficult conditions of patients seeking surgical treatment, we aimed to investigate whether or not there are significant differences between patients seeking cosmetic surgery and patients seeking surgical treatment in the rate of vitality, depression, anxiety, and stress.

Participants
The study included 80 (47 female and 33 male) patients seeking either cosmetic surgery (n ¼ 40) or surgical treatment (n ¼ 40), with a mean age of 28.98 (SD ¼ 8.32), who had been referred to the Shahid Motahhari clinic in Shiraz, Iran. The patients seeking cosmetic surgery were generally undergoing surgery on their nose, face, ears, eyebrows, eyelashes, or jaw, or were having Botox, whereas the patients seeking surgical treatment were generally needing treatment for a broken or crooked nose, their hands, neck, or hemorrhoids, a laparoscopy, sinusitis, and ear and throat problems.

Instruments
The Contingencies of Self-Worth Scale. The Contingencies of Self-Worth Scale (Crocker et al., 2003) consists of 35 items in seven areas of life, which are divided into two broad categories: (1) internal contingencies of selfworth-God's love (e.g., My self-worth is based on God's love) and virtue (e.g., Doing something I know is wrong makes me lose my self-respect)-and (2) external contingencies of self-worth-family support (e.g., Knowing that my family members love me makes me feel good about myself); appearance (e.g., When I think I look attractive, I feel good about myself); approval from others (e.g., I can't respect myself if others don't respect me); competition (e.g., I feel worthwhile when I perform better than others on a task or skill); and academic competence (e.g., My self-esteem is influenced by my academic performance)-on which people's worth is dependent. Each item in the Contingencies of Self-Worth Scale is scored on a 7-point Likert scale (1 ¼ strongly disagree to 7 ¼ strongly agree). In Crocker et al.'s (2003) study, which was conducted on 795 students, a retest reliability of .68 to .92 was obtained at 3 months and of .51 to .88 at 8.5 months. Each subscale had a high internal consistency with an alpha ranging from .82 to .96. This scale was validated on 502 students in Iran by SabzeAra Langroodi et al. (2014), the results of which showed that the scale had acceptable convergent and divergent validity, as well as internal consistency. In this study, the final Cronbach's alpha for the subscales of the contingencies of selfworth were .67 for family support (Items 2 and 10 removed); .70 for competition (Item 32 removed); .60 for appearance (Item 1 removed); .68 for God's love; .63 for academic competence (Item 13 removed); .66 for virtue; and .72 for others' approval. Because some of the subscales had an unacceptable Cronbach's alpha, we removed items that weakened the reliability based on the recommendation of the "scale if item deleted" method in SPSS (Robinson, 2018). Accordingly, we removed Items 2 and 10 for family support, Item 32 for competition, Item 1 for appearance, and Item 13 for academic competence. The Integrative Self-Knowledge Scale. The Integrative Self-Knowledge Scale (Ghorbani et al., 2008) consists of 12 items (e.g., If I need to, I can reflect about myself and clearly understand the feelings and attitudes behind my past behaviors) which are scored on a 5-point Likert scale (0 ¼ mostly false to 4 ¼ mostly true). Ghorbani et al. (2008) developed the scale and validated it in a study conducted on a sample of 723 Iranian and 900 American individuals. The results of the study indicated that the Integrative Self-Knowledge Scale had good internal reliability and equivalence of measurement along with incremental, discriminant, criterion, and convergent validity. A Cronbach's alpha coefficient of .78 was obtained for the scale in this study.
The Subjective Vitality Scale. The Subjective Vitality Scale (Ryan & Frederick, 1997) has seven questions which measure people's current feeling of vitality (e.g., I look forward to each new day). This scale evaluates responses on a 7-point range (1 ¼ completely false to 7 ¼ completely true). A high score in this scale suggests the high energy, high spirits, and, in general, high vitality of the individual. The Subjective Vitality Scale was validated in Iran by Tanhaye Reshvanloo et al. (2018); the confirmatory validity and gender invariance were confirmed, and the Cronbach's alpha and split-half coefficients for the scale were .88 and .85, respectively. A Cronbach's alpha coefficient of .84 was obtained for the scale in the present study.
The Depression Anxiety Stress Scale-21. The Depression Anxiety Stress Scale-21 (Lovibond & Lovibond, 1995) measures the three clinical symptoms of depression (e.g., I didn't experience any positive feelings), anxiety (e.g., I felt afraid for no reason), and stress (e.g., I felt restless) on a 4-point range (0 ¼ not at all to 3 ¼ high). In Iran, this scale has been used in many studies and has good validity and reliability (e.g., . In this study, the Cronbach's alpha coefficients for the subscales of depression, anxiety, and stress were .80, .81, and .79, respectively.

Procedure
The records of individuals who had been referred to specialists in plastic surgery were examined, and interviews with the doctor of each patient were undertaken to determine the reason for their desire to undergo surgery (either cosmetic, which focuses on enhancing a patient's appearance, or therapeutic, which aims to correct functional impairments). Forty patients seeking cosmetic surgery and forty patients seeking surgical treatment were selected. The eligibility criteria for the patients seeking cosmetic surgery included a history of having cosmetic surgery or seriously intending to do so, based on the cosmetic surgeon's assessments, and being at least 15 years of age. Individuals were excluded from participation if they had a history of diagnosis of mental disorders or a physical disability, or were illiterate. However, the individuals in the treatment control group had no history of or intention to undergo cosmetic surgery, included persons over the age of 18, had no record of mental disorders, and needed surgery for impairments based on the plastic surgeon's assessments. The selected participants were given general information and instructions. Questionnaires, translated into Farsi and based on previous studies in Iran, were completed by the participants without them being informed about the goals of the study to avoid bias in their responses. In order to comply with ethical issues in research, prior to the study, the participants were informed about the voluntary nature of their participation and the nondisclosure of their private information, and their consent was obtained to participate in the study. The procedure performed in the research was also in accordance with the 1964 Declaration of Helsinki.

Data Analysis
Frequencies, percentages, means, and chi-square tests (v 2 ) were used to compare the demographic features of the patients having cosmetic surgery with those having surgical treatment (see Table 1). The Kolmogorov-Smirnov test for normality was also performed for all of the study's variables. The results indicated that none of the variables had a significant difference, with the hypothetical normal distribution suggesting that the data were normally distributed (p > .05). Thereafter, to compare self-knowledge and vitality between the cosmetic surgery and surgical treatment groups, two independent t tests were performed separately ( Table 2). In order to compare the extent of contingencies of self-worth and subscales of depression, anxiety, and stress between the two groups, a multivariate analysis of variance (MANOVA) was used separately (Table 3). In order to compare the cosmetic surgery and surgical treatment groups by considering internal (God's love and virtue) and external (family support, appearance, others' approval, competition, and academic competence) contingencies of self-worth, a MANOVA was used. A multivariate analysis of covariance (MANCOVA) was used to compare the cosmetic surgery and surgical treatment groups on internal and external contingencies of self-worth by controlling the self-knowledge variable. This was done to answer the question of whether or not, by controlling the selfknowledge variable, the difference between the two groups would change in terms of the contingencies of self-worth. We also used partial eta-squared values (g 2 p ) as a measure of effect size, presenting the magnitude of the reported effects in a standardized metric (Lakens, 2013) to interpret the results. Cohen (1988) suggests that .2 be considered a small effect size, .5 a medium effect size, and .8 a large effect size. Prior to conducting the test, independent t test, MANOVA, and MANCOVA (e.g., the Box's M and Levene's tests), the assumptions were examined, which indicated no significant differences in error variance and the covariance matrix of the dependent variables between the two groups. Therefore, the assumptions of the tests were considered. SPSS 21.0 statistical software was used for the statistical analysis in this study.

Results
The results of the chi-squared tests indicated that the cosmetic surgery and surgical treatment groups were not significantly different in terms of their demographic variables, including gender, age, economic status, education, marital status, ethnicity, place of residence and place of birth, and thereby were relatively homogeneous (see Table 1).
The results of the t test (assuming equal variances) showed that there was a significant difference between the two groups in the rate of self-knowledge, t(1, 78) ¼ 3.41, g 2 ¼ .13, p < .001, with the cosmetic surgery group having a lower integrative self-knowledge compared to the surgical treatment group. However, its effect size was .13, indicating that the magnitude of differences between the two groups in terms of their selfknowledge is small. By assuming unequal variances between the groups, F(1, 78) ¼ 6.70, p ¼ .01, the result of the t test showed that there was no significant difference between the two groups in the rate of vitality, t (1, 78) ¼ 0.47, g 2 ¼ .01, p ¼ .637 (see Table 2). Prior to the MANOVA, its assumptions were examined. The results of the Box's M, F(28, 2.12) ¼ 1.16, p ¼ .251, and Levene's tests did not show significant differences in error variance and the covariance matrix of the dependent variables between the two groups. Therefore, the assumption to use a MANOVA test was considered. However, the results of the fourfold MANOVA tests indicated significant differences-for example, Wilks's lambda ¼ .71, F(7, 72) ¼ 4.17, g 2 ¼ .29, p ¼ .001. This finding suggests that there is a significant difference between the two groups at least in one of the dependent variables. The test results showed that the seven contingencies of selfworth for the two groups studied only had significant differences in contingencies of self-worth to appearance, F(1, 78) ¼ 13.85, g 2 ¼ .15, p < .001, and the approval of others, F(1, 78) ¼ 12.68, g 2 ¼ .14, p < .001. The cosmetic surgery group had a significantly higher mean (M ¼ 4.77, SD ¼ 1.03) than the surgical treatment group (M ¼ 3.83, SD ¼ 1.22) in contingencies of selfworth to appearance. It also had higher scores (M ¼ 4.34, SD ¼ 1.29) than the surgical treatment group (M ¼ 3.28, SD ¼ 1.36) in contingencies of selfworth to others' approval. The effect sizes for appearance and approval of others were .15 and .14, respectively, indicating that the magnitude of differences between the two groups in terms of the two dependent variables is small (see Table 3).
The results of the fourfold MANOVA tests indicated no significant differences between the two groups in terms of depression, anxiety, and stress-for example, Wilks's lambda ¼ .96, F(3, 76) ¼ 0.91, g 2 ¼ .03, p ¼ .437. Hence, patients seeking cosmetic surgery and surgical treatment had no significant differences in any of the depression, anxiety, and stress variables (see Table 3).
In order to compare the cosmetic surgery and surgical treatment groups with regard to internal and external contingencies of self-worth, a MANOVA test was used. Prior to this test, the results of the Box's M test showed no significant difference, F(3, 1.09) ¼ 0.23, p ¼ .872. Similarly, the results of the Levene's test for the dependent variables of internal, F(1, 78) ¼ 0.50, p ¼ .482, and external, F(1, 78) ¼ 0.17, p ¼ .678, contingencies of self-worth were not significant. The results indicated that all of the fourfold MANOVA tests were significantly different-for example, Wilks's lambda ¼ .82, F(2, 77) ¼ 8.29, g 2 ¼ .18, p ¼ .001. The results showed that there was a significant difference between the cosmetic surgery and surgical treatment groups in internal, F(1, 78) ¼ 5.39, g 2 ¼ .06, p ¼ .023, and external, F(1, 78) ¼ 4.36, g 2 ¼ .04, p ¼ .040, contingencies of self-worth. This suggests that patients who undergo cosmetic surgeries have lower internal but higher external contingencies of self-worth compared to patients seeking surgical treatment. The effect sizes for internal and external self-worth between the two groups were too small.
The results also showed that by controlling the selfknowledge variable, no significant between-group differences were observed in internal contingencies of selfworth, F(1, 77) ¼ 2.57, g 2 ¼ .03, p ¼ .113. However, between-group differences still remained significant in terms of external contingencies of self-worth, F(1, 77) ¼ 4.45, g 2 ¼ .05, p ¼ .039. This means that selfknowledge can reduce the difference between the cosmetic surgery and surgical treatment groups in terms of internal contingencies of self-worth. Its effect size was .05, indicating that the magnitude of differences between the two groups in terms of their external contingencies of self-worth after controlling for selfknowledge is very small.

Discussion
Overall, the aim of this study was to examine the psychological structures, contingencies of self-worth, and self-knowledge among patients seeking cosmetic surgery. We found that patients seeking cosmetic surgery considered their worth as mostly dependent on their appearance and the approval of others. This finding is consistent with the findings of other studies (e.g., Delinsky, 2005;Park et al., 2009;Tam, 2013). Although their effect sizes were small, these findings are important and can be explained from different standpoints. For example, Sarwer et al. (1998) argue that people whose self-esteem is not dependent on their appearance are less likely to undergo cosmetic surgery, regardless of their satisfaction with their body image. In contrast, people whose self-esteem depends on their appearance are more likely to seek cosmetic surgery. According to Crocker (2002), the contingencies of self-worth are associated with areas in which success or failure results in an increase or decrease in self-esteem. Because people try to maintain and increase their self-confidence, they follow situations and engage in activities which provide them with the opportunity to succeed and prevent them from failure in areas which endanger their self-worth. Accordingly, those whose self-worth depends on their appearance and the approval of others undergo activities like cosmetic surgery to strengthen their worth. However, the contingencies of self-worth also involve psychological vulnerability. Success or failure in areas in which a person is interested can lead to an increase or decrease in areas related to self-esteem; thus, vulnerability in self-worth (appearance and others' approval) indicates a high sensitivity to appearance-based rejection and thereby is associated with an increased desire for cosmetic surgery (Park et al., 2009). Crocker et al. (2003 concluded that the contingencies of self-worth predict certain activities (e.g., how we spend our time). Therefore, it could be suggested that those with contingencies of self-worth to appearance and others' approval may modify their appearance to increase their selfworth.
Another finding of the present study was that patients seeking cosmetic surgery had lower selfknowledge compared to patients undergoing surgical treatment. This result is consistent with the results of Zarandi et al. (2012), which show that low selfknowledge predicts a tendency toward cosmetic surgery. Self-knowledge is a self-regulatory process that leads to the well-being of the self (Ghorbani et al., 2003); thus, it can be assumed that people with low self-knowledge may have impaired self-regulation. For these people, cosmetic surgery is a way of avoiding negative feelings. In this way, cosmetic surgery may act as a defense method against criticism. Similarly, prior studies have shown that most patients seeking cosmetic surgery have a distorted body image (Dakanalis et al., 2013;Modabber Vahed & Hamidi, 2016;Mulkens et al., 2012;Soest et al., 2009). A low self-knowledge causes people to be inflexible in their thoughts and emotions, and they cannot accept their body unconditionally; this lack of flexibility raises problems associated with their body image and negative judgments about their appearance (Naami & Salehi, 2016). In contrast, people who have high self-knowledge make more accurate self-judgments (Silvia & Gendolla, 2001) and possess an integrated self which can unite their negative and positive beliefs about themselves (Showers & Kling, 1996). Further, self-knowledge is an integrated process which attempts to give meaning to experiences and attitudes of self. Because it involves knowledge of the present and tries to associate it with one's past experiences (Ghorbani et al., 2003), people with high self-knowledge are interested in promoting themselves, and thus prefer time comparisons (the past versus present self) to social comparisons, which is one of the reasons underlying the tendency to undergo cosmetic surgery.
No significant difference was found between the cosmetic surgery and surgical treatment groups in the rate of vitality or clinical symptoms (depression, anxiety, and stress). Although several studies have found that patients seeking cosmetic surgery show mood and emotional disorders compared to the normal population (e.g., Collins et al., 2014;Mulkens et al., 2012), these results have been obtained by comparing cosmetic surgery with the normal population rather than the surgical treatment population. In fact, people seeking surgical treatment have various problems (e.g., a broken or crooked nose or hemorrhoids), which leads them to suffer from emotional disturbances. This may lead to insignificant differences between the two groups. These results also showed that people who undergo cosmetic surgery have lower internal and higher external contingencies of self-worth. This finding is consistent with those of previous studies which indicated that external contingencies of self-worth had a direct relationship with the tendency to undergo cosmetic surgery (Park et al., 2009). The results also showed that by controlling the self-knowledge variable, the between-group differences in internal contingencies of self-worth lost their significance as opposed to the external contingencies. In fact, this result indicates that self-knowledge, as may be suggested by the word itself, performed as an intra-psychological variable as it could significantly affect internal but not external contingencies of self-worth. Accordingly, improving self-knowledge of people seeking for cosmetic surgery can lead their self-worth to the internal areas rather than on external areas, and then this in turn may lead to a lower tendency to seek cosmetic surgery and higher psychological well-being.

Limitations
This study has limitations, which should be considered when interpreting the results, as well as in future studies. We relied solely on self-report and correlational analyses. Therefore, a cause-and-effect relationship cannot be inferred from the results obtained in this study. Furthermore, as the present study was conducted only in one city in Iran, cultural factors should be taken into account, because these factors influence some variables, such as self-knowledge (Ghorbani & Watson, 2005) and contingencies of self-worth. On the other hand, the present study had a number of strengths, including a relatively large sample size and the use of a general surgery group as a comparison for the cosmetic surgery group to control for factors that may be related to surgery in general.

Conclusion
These findings have useful clinical implications for clinicians, physicians, psychologists, and therapists. In hospitals and clinics, those seeking cosmetic surgery could be screened in terms of their contingencies of self-worth and self-knowledge before undergoing surgery. If a patient has a tendency to undergo cosmetic surgery due to their dependence on contingencies of self-worth to appearance and the approval of others, or in general external contingencies of self-worth or low selfknowledge, they could be provided with counseling and psycho-educational training to shift their dependence on specific domains (appearance and others' approval) and thereby reduce their likelihood of seeking cosmetic surgery and their vulnerability to psychological distress. Moreover, they could be encouraged to believe in their self unconditionally and try to promote their understanding of their self and body knowledge so that they have a less distorted and more accurate judgment of their situation and psychological status. Above all, promoting self-knowledge can create an integrated self which unites negative and positive beliefs about the self. Consequently, instead of being engaged in social comparisons, these people should engage in longitudinal comparisons between their past self and their present self, which can lead to the promotion and development of the self and result in satisfaction and assurance (Wilson & Ross, 2000).