Exploring the Relationships Between Internalised Stigma, Loneliness, and Mental Well-Being Among Sex Workers

Sex work is one of the most stigmatised professions in the world. Although research examining other stigmatised populations has found associations between internalised stigma, increased loneliness, and poorer mental well-being, there is limited research examining these associations for sex workers. This is concerning, considering Corrigan’s theory that internalised stigma, as well as external stigma, reduces opportunities of stigmatised persons. Further, internalised stigma, loneliness, and poorer well-being have been associated with significant social, mental, and physical consequences for stigmatised populations. As such, this exploratory study investigated sex workers’ internalised stigma, and its relationship with their mental well-being and experience of loneliness. 56 full-service sex workers (78.6% females, 12.5% non-binary, 8.9% males, ranging from 18 to 43 years old) completed an online, cross-sectional survey measuring their self-reported internalised stigma, loneliness, and mental well-being. Hierarchical multiple regression analyses (MRAs) supported the hypotheses that higher internalised stigma would significantly predict lower mental well-being and higher loneliness after controlling for age and gender. Internalised stigma accounted for a significant 39.3% of the variance in loneliness, and a significant 12.6% of the variance in mental well-being. Correlations supported the hypothesis that higher loneliness would significantly, negatively correlate with mental well-being after controlling for age. Findings aligned with prior research and supported Corrigan. Limitations of the study are discussed, including the small sample size and the cross-sectional, self-report research design. Identified areas of focus for future research and practice include consideration of other associates of internalised stigma for sex workers, as well as lessening the consequences of stigmatisation for sex workers through reduction of its internalisation.


Introduction
Sex work, or the exchange of sexual services for monetary or other reward between consenting adults, may be considered one of the most enduring professions to exist in modern society (García et al., 2017;Grittner & Walsh, 2020). For centuries, sex work has confounded policy makers and captivated the community (García et al., 2017;Lerner, 1986;Peršak & Vermeulen, 2014). Despite the evolution of sex work over time, policies and perceptions continue to reflect views of the profession as categorically immoral or exploitative (García et al., 2017;Lerner, 1986;McKenzie et al., 2021;Peršak & Vermeulen, 2014;Showden & Majic 2014). As a result, sex work remains one of the most stigmatised professions in the contemporary world (Dourado et al., 2019;Jiao & Bungay, 2019;Krüsi et al., 2016).

Stigma
Early stigma theory by Goffman (1963) defined stigma as "an attribute that is deeply discrediting" which reduces someone in others' minds "from a whole and usual person to a tainted, discounted one" (Goffman, 1963, p. 3). Pryor & Reeder (2011) described four interrelated forms of stigma: (1) public stigma, which is at the centre of the model and represents a collective understanding that an attribute is devalued, as well as peoples' social and psychological reactions to those they perceive as having that attribute; (2) self-stigma, or the social and psychological impact of possessing a stigmatised attribute, including feelings of shame and apprehension of discrimination; (3) stigma by association, or the social and psychological responses to people associated with a stigmatised person, as well as the associated person's response to this association, and; (4) structural stigma, or the institutional and ideological validation and preservation of stigmatisation (Bos et al., 2013;Pryor & Reeder, 2011). Fundamentally, stigma may be understood as negative views attributed to, or discrimination against, persons or groups for characteristics or behaviours perceived as differing from, or inferior to, social norms (Bos et al., 2013;Dovidio et al., 2000;Dudley, 2000;Grittner & Walsh, 2020;Scambler, 2009).
Such examples of stigma may also be conceptualised as external stigma. External stigma, also known as enacted stigma, refers to the experience of unfair treatment or discrimination perpetrated by others (Gray, 2002). External stigma persists despite efforts at its reduction, which include altering the language around sex work, reinforcing the legitimacy of the profession, classifying violence perpetrated against sex workers as a hate crime, and jurisdictional decriminalisation of the profession (Ham & Gerard, 2014;Sanders, 2016).
It has been theorised that stigmas result from a perception that the stigmatised attribute threatens the social norms and population survival (including disease avoidance) of societies (Benoit et al., 2018a;Hallgrímsdóttir et al., 2008;Phelan et al., 2008;Scambler, 2009). As such, individual and institutional perceptions of sex workers as unhygienic or amoral may be a significant contributor to why sex work and sex workers remain persistently stigmatised.
Different forms of sex work may also be associated with different levels of stigma or exposure to stigma: Compared to indoor sex work, outdoor sex work has been associated with less access to healthcare, increased risk of arrest and negative experiences with law enforcement, and greater likelihood of being denied social services, possibly due to increased visibility (Benoit et al., 2018b;Klambauer, 2017;Preble et al., 2019).

Consequences of Stigma
The consequences of external stigma for stigmatised persons are extensive. Significant deleterious consequences of stigmatisation among other marginalised populations, such as people with mental illness, disabilities, and Human Immunodeficiency Virus (HIV), include: Social isolation, emotional distress, and lower income and employment (Benoit et al., 2018a;Bunn et al., 2007;Gray, 2002;Green et al., 2005;Link & Phelan, 2001;Link & Hatzenbuehler, 2016). Researchers have also argued that stigma in general is a key perpetuant of social inequality, due to its association with reduced life chances; such as education, employment, housing, health and health care, identity creation, income, and social relationships (Link & Hatzenbuehler, 2016;Link & Phelan, 1995, 2001. These reduced life chances have also been associated with reduced physical and mental health, overall well-being, and quality of life (Hatzenbuehler & Link, 2014;Link & Hatzenbuehler, 2016).

Internalised Stigma
Clearly, there is significant research documenting the experiences of external stigma for sex workers, as well as the consequences of stigmatisation for other stigmatised populations. However, there is comparably little research documenting the consequences of internalised stigma for sex workers, or self-stigma as conceptualised within Pryor and Reeder's (2011) model. Internalised stigma is the extent to which stigmatised persons internalise external stigma, resulting in expectations of discrimination and feelings of shame (Gray, 2002). Greater experienced external stigma has been associated with greater internalised stigma (Vogel et al., 2013). As sex workers have been demonstrated to face significant external stigma, it stands to reason that they are at a greater risk than non-stigmatised populations of experiencing internalised stigma and associated consequences.
Further, it is reasonable to assume that stigma is internalised by sex workers due to the consequences of stigma found by previous studies within this population, despite that these studies did not necessarily use the term 'internalised stigma'. Such consequences include psychological distress, social isolation, lower income, lower employment rates, increased physical and mental health problems, and increased drug use (Benoit et al., 2018a;Benoit et al., 2015;Link & Phelan 2001;Vanwesenbeeck, 2001).

Internalised Stigma, Loneliness, and Well-being
In other stigmatised populations, such consequences of internalised stigma have included loneliness (Kong et al., 2021;Świtaj et al., 2014;Yildirim & Kavak Budak, 2020) and poorer well-being (Mak et al., 2007;Pérez-Garín et al., 2017;Rose et al., 2019;Yeung et al., 2021), both of which have also been associated independently (Doman & Le Roux, 2012;Golden et al., 2009). Loneliness refers to an unpleasant subjective state arising from a person's perceived discrepancy between the level of support or companionship they want, and that which is presently accessible to them (Blazer, 2002;Golden et al., 2009). The World Health Organization (2004) defines mental well-being as "a state… in which the individual realizes his or her own abilities, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to his or her community" (World Health Organization, 2004, p. 10). Kong et al. (2021) found that internalised-stigma significantly predicted loneliness in a sample of visually-impaired college students. Yildirim & Kavak Budak (2020) found a strong, statistically significant correlation between internalised stigma and loneliness. When examining the experiences of people with Human Immunodeficiency Virus and Acquired Immunodeficiency Syndrome (HIV/AIDS), Mak et al. (2007) found that participants' internalised stigma negatively correlated with their well-being and perceived social support, and positively correlated with psychological distress (Mak et al., 2007). Rose et al. (2019) found that internalised stigma was associated with poorer overall well-being in a sample of high school students, as well as five subscales of well-being (i.e., autonomy, environmental mastery, personal growth, positive relations with others, and self-acceptance). Another study found that internalised stigma was associated with higher loneliness, less perceived social support, and higher psychological distress in a sample of domestic helpers in Hong Kong (Yeung et al., 2021).
Regarding the mechanisms of the above associations between stigma, loneliness, and well-being, Corrigan (2004) theorised that stigma reduces the social opportunities of stigmatised persons directly, through discrimination and rejection (i.e., public and structural stigma); as well as indirectly, through stigmatised persons' self-censorship as a result of prior negative experiences (i.e., internalised stigma). Further, internalised stigma leads to shame and can negatively impact self-esteem, which has been demonstrated as a predictor of well-being (Corrigan, 2004;Diener & Diener 1995;Du et al., 2017).

Consideration of Age and Gender
Age and gender have also been explored in the literature for their association with internalised stigma, loneliness, and well-being; albeit with mixed results. For example, while some studies report negative associations between age and internalised stigma (Barney et al., 2010;Mackenzie et al., 2019a), a systematic review and meta-analysis found no such association (Livingston & Boyd, 2010). Similarly, although females reported significantly higher internalised stigma than males in a sample of people with HIV (Li et al., 2017), no relationship between gender and internalised stigma was found in a separate sample of people with psychotic and mood disorders (Szcześniak et al., 2018).
Previous research into age-based differences in loneliness has yielded similarly varied outcomes: Jylhä (2004) reported that cross-sectional analyses showed that the percentage of participants experiencing loneliness increased with their age group. However, subsequent multivariate analysis found no independent association between age and loneliness (Jylhä, 2004). Yang & Victor (2011) reported that the prevalence of loneliness did increase with age for their multi-national sample, though Victor & Yang (2012) reported that the curve for the prevalence of loneliness was U-shaped, as loneliness increased in both younger and older age groups. In terms of gender differences, some studies suggest that males may be lonelier than females (Barreto et al., 2021;Maes et al., 2019;van den Broek, 2017), while others suggest the opposite (Jylhä, 2004;Victor & Yang, 2012) or that loneliness is comparable for males and females throughout the lifespan (Maes et al., 2019).
Existing literature suggests that reported positive associations found between age and well-being (Abdullahi et al., 2019;Xing & Huang, 2014) may not be generalisable across cultures (Steptoe et al., 2015). In terms of gender, Gómez-Baya et al. (2018) found that women reported lower psychological well-being than men in their sample of European health professionals. However, a meta-analysis by Batz- Barbarich et al.(2018) found no significant gender differences in well-being.

Research Aims
Although associations between internalised stigma, loneliness, and well-being have been described in prior research examining other stigmatised populations, there is little literature examining associates of internalised stigma for sex workers. Stigma has been associated with social isolation, lower income and rates of employment, and increased physical and mental health problems, perhaps due to a reluctance to engage with health services for fear of further stigmatisation (Benoit et al., 2018a;Link & Phelan, 2001). Lower well-being has been associated with increased health problems, unemployment, and social isolation (Dolan et al., 2008). Loneliness has been associated with diminished quality of life, suicidal ideation, and suicide risk (Bennardi et al., 2019;Niu et al., 2020;Rumas et al., 2021). As such, understanding the associates of internalised stigma is the first step towards mitigating them, which is critically important for preventing potentially harmful consequences for stigmatised populations, including sex workers.
As such, this exploratory study aimed to add to stigma research by focusing on sex workers' internalised stigma, and its relationship with their mental well-being and loneliness. Age and gender were also considered as covariates, due to their noted associations with these variables.
Based on the existing literature, three hypotheses were considered: First, that higher internalised stigma would significantly predict higher loneliness, after controlling for age and gender; second, that higher internalised stigma would significantly predict lower mental well-being, after controlling for age and gender; and third, that loneliness would significantly, negatively correlate with mental well-being after controlling for age.

Participants
The sample consisted of 56 full service sex workers (78.6% females, 12.5% nonbinary, 8.9% males, ranging from 18 to 43 years old; M = 27.82, SD = 6.44). The length of time as a sex worker was between less than one year to 12 years (M = 3.98, SD = 3.09). Participants were recruited worldwide via unpaid advertisements on social networking platforms (Instagram, Twitter, Facebook, and Reddit). In order to meet the study eligibility requirements, participants were required to be at least 18 years of age and identify as full-service sex workers, indicating provision of inperson sex services (Sawicki et al., 2019). Participants did not receive any monetary reimbursement for their participation.

Mental Well-being
World Health Organisation -Five Well-being Index (WHO-5). The 5-item WHO-5 was used to measure mental well-being. Participants responded to statements about their previous two weeks, such as "I have felt cheerful and in good spirits", using a 5-point Likert scale ranging from 0 (At no time) to 5 (Most of the time). Well-being scores were obtained by summing all items, where higher scores represented higher levels of mental well-being (World Health Organization, 1998).
Previous studies have shown adequate psychometric properties for the WHO-5, including construct validity and reliability (Topp et al., 2015). The reliability estimate for the current sample was strong (α = 0.90) according to the conventions of Carmines & Zeller (1979). Although there are no universally-supported cut-off scores or norms for the WHO-5, a cut-off score below 50 has been suggested as indicative of depression. The WHO-5 was used due to its established reliability and validity, and because it is considered one of the most widely used scales assessing psychological well-being (Topp et al., 2015).

UCLA Loneliness Scale (Version 3).
The 20-item UCLA Loneliness Scale (Version 3) was used to assess levels of loneliness. Participants were asked to respond to questions such as "How often do you feel that there is no one you can turn to?" using a 4-point Likert scale ranging from 1 (Never) to 4 (Always). After reverse scoring the nine negatively worded items, the loneliness score was obtained by summing all items on the UCLA Loneliness Scale, whereby higher scores indicated higher levels of loneliness (Russell, 1996).
Previous studies have shown the UCLA Loneliness Scale (Version 3) to have adequate psychometric properties. This was demonstrated through data collected in four previous studies using students, nurses, teachers, and the elderly (Russell, 1996). There was evidence for the convergent validity of the Version 3 scale, as demonstrated by strong, significant correlations with the NYU Loneliness Scale (Rubenstein & Shaver, 1982) and the Differential Loneliness Scale (Schmidt & Sermat, 1983). Similarly, the Version 3 scale demonstrated discriminant validity through its negative correlations with social support. The reliability of the Version 3 scale also appeared to be good (α = 0.89 − 0.94) (Russell, 1996). The reliability estimate for the current sample was excellent (α = 0.93) (Carmines & Zeller, 1979). The UCLA Loneliness Scale specifies no cut-off scores or norms for score comparisons (Russell, 1996). The UCLA Loneliness Scale was selected due to its adequate psychometric properties and its utilisation in other studies examining correlations between stigma, well-being, and loneliness (Kong et al., 2021;Yeung et al., 2021;Yildirim & Kavak Budak, 2020).

Internalised Stigma
Modified HIV Stigma Scale. As no scale existed that measured perceptions of stigma in sex workers, the HIV Stigma Scale (Berger et al., 2001;Bunn et al., 2007) was modified to assist with assessment. This involved changing the wording of the items. For example, "I worry that people may judge me when they learn that I have HIV/AIDS" to "I worry that people may judge me when they learn that I am a sex worker". The modified scale had 33-items, and participants were asked to respond to each statement using a 4-point Likert scale ranging from 1 (Strongly Disagree) to 4 (Strongly Agree). After reverse scoring two items in the scale, The Sex Worker Stigma Score was obtained by summing all 33 items. Higher scores indicated greater levels of perceived internalised stigma.
The modified version of the HIV Stigma Scale was necessary to specifically target sex workers. While this modified scale has not been validated, previous studies have shown the HIV Stigma Scale to have adequate psychometric properties. The HIV Stigma Scale is a well-validated measure, with construct validity demonstrated through relationships between related measures of self-esteem, depression, social support, social integration, and social conflict being consistent with predictions (Berger et al., 2001). Additionally, the HIV Stigma Scale was found to have accept-able internal reliability, indicated by a Cronbach's alpha for the overall scale and all subscales of 0.90 or greater, and a test-retest reliability of 0.87 or greater (Berger et al., 2001). The reliability estimate for the current sample was also strong (α = 0.90). No norms or cut-off scores for the existing HIV Stigma Scale were indicated by existing literature.

Procedure
Ethics Approval for the research project was granted by the Sunshine Coast University Ethics Board (Ethics Approval Number S201431). Data collection was completed between July and October of 2020. Participants were directed to the study via social media networking sites by a link to the online survey. The explanatory statement described the study's purpose, as well as the risks and benefits of participating. Respondents were informed that participation was voluntary and anonymous. The study was described as an exploration of the relationships between internalised stigma, well-being, and loneliness among sex workers. After providing consent, participants were asked to complete the demographic questionnaire followed by the psychometric measures. This took approximately 15min to complete. Upon completion, participants were directed to the debriefing statement that thanked them for their time and provided links for support. Participants were then given information on how their data would be stored anonymously following completion of the project.

Data Analysis
The data was analysed using the software IBM SPSS Statistics for Windows, Version 27.0 (IBM Corp, 2020). Analysis using G*Power (Faul et al., 2009) specified that a minimum of 54 participants was required for the study to have adequate power, which was met.

Hierarchical Multiple Regression Analyses
Hierarchical multiple regression analyses (MRAs) were used to assess relationships between internalised stigma, mental well-being, and loneliness after controlling for age and gender. The importance of the predictor variables within the MRAs was assessed using R 2 , which was used to determine the percentage of variance of each outcome variable accounted for by each predictor variable. Effect size was measured using Cohen's f 2 and interpreted using Cohen's (1988) specifications, whereby small, medium, and large effect sizes were denoted by f 2 ≥ 0.02, f 2 ≥ 0.15, and f 2 ≥ 0.35, respectively (Cohen, 1988;Selya et al., 2012).
Several assumptions were evaluated and found to be met. There was independence of residuals, as assessed by Durbin-Watson statistics of 1.799 (loneliness and stigma) and 1.526 (mental well-being and stigma). Boxplots indicated that variables were normally distributed. Although the boxplot for internalised stigma showed two univariate outliers, this was deemed too mild a departure from normality to be of concern. Inspection of the normal probability plot of standardised residuals, and the scatterplot of standardised residuals against standardised predicted values, supported the assumptions of normality, linearity, and homoscedasticity. Mahalanobis distance did not exceed the critical χ 2 for df = 3 (at α = 0.001) of 16.27 for any cases, indicating that multivariate outliers were not of concern. Tolerance values greater than 0.1 for all three predictor variables in the final regression model indicated that multicollinearity would not interfere with outcome interpretations (Allen et al., 2014;Field, 2015).

Bivariate Pearson's Correlation with Pearson's Partial Correlation
To test the hypothesis that higher loneliness would significantly, negatively correlate with mental well-being after controlling for age, a Bivariate Pearson's correlation and Pearson's Partial Correlation were performed. Effect size was measured using the Pearson's correlation coefficient (r) and interpreted using Cohen's (1988) specifications, whereby small, medium, and large effect sizes were denoted by r ≥ .1, r ≥ .3, and r ≥ 0. 5, respectively (Allen et al., 2014;Cohen, 1988).
Visual inspection of the normal Q-Q and detrended Q-Q plots for each variable confirmed normal distribution. Visual inspection of a scatterplot of well-being against loneliness confirmed that the relationship between these variables was linear and heteroscedastic. Further, there was univariate normality, as assessed by non-significant outcomes on the Shapiro-Wilk test (p < .05) (Allen et al., 2014;Field, 2015).
Pearson's correlations between each variable are reported in Table1. Unstandardised (B) and standardised (β) regression coefficients, and squared semi-partial correlations (sr 2 ) for each predictor on each step of the hierarchical MRA's are reported in Table2. As can be seen in Table2, gender (sr 2 = 0.06) and internalised stigma (sr 2 = 0.39) were both significant predictors of loneliness in the final regression model. Significant predictors of mental well-being were age (sr 2 = 0.00) and internalised stigma (sr 2 = 0.13).

Loneliness and Mental Well-being
As can be seen in Table1, a Bivariate Pearson's correlation established that there was a moderate negative, statistically significant linear relationship between wellbeing and loneliness, r(54) = − 0.386, p = .003. A Pearson's Partial correlation showed that the strength of this linear relationship was less when age was controlled for, r partial (53) = − 0.358, though still statistically significant, p = .007.

Discussion
This study examined relationships between sex workers' self-reported experience of internalised stigma, loneliness, and mental well-being. The three hypotheses were supported, as higher internalised stigma significantly predicted higher loneliness and lower mental well-being after controlling for age and gender, and loneliness significantly, negatively correlated with mental well-being after controlling for age.
The results of the current study appear to support Corrigan's (2004) theory through the links found between internalised stigma, loneliness, and mental well-being. Specifically, that stigma reduces the social opportunities of stigmatised persons not only directly, through external public or structural manifestations of stigma, but also through internalisation of this stigma (Corrigan, 2004;Diener & Diener 1995;Du et al., 2017).

Internalised Stigma and Loneliness
Internalised stigma was found to be a significant, positive predictor of loneliness after accounting for the combined effect of age and gender, supporting the first hypothesis. The positive association between internalised stigma and loneliness found in this study supports prior research, which found that greater internalised stigma was associated with greater loneliness in other populations, including students with visual impairments and people with schizophrenia or other psychotic disorders (Kong et al., 2021;Świtaj et al., 2014;Yildirim & Kavak Budak, 2020).
Notably, gender was also found to be a significant predictor of loneliness after internalised stigma was added to the regression model. This suggests that internalised stigma may mediate the relationship between gender and loneliness within this population. Although the observed association between gender and loneliness was positive, it is important to note that the values used to code gender for the purpose of the regression analyses (i.e., female as 1, non-binary as 2, and male as 3) were assigned arbitrarily. Thus, the finding may be an artefact, and neither the direction of the relationship, nor potential gender differences in the strength of the relationship, should be interpreted from these results.
This association between gender and loneliness in the final regression model did not align with prior research, which reported no similar effects of gender when examining associations between internalised stigma and loneliness (Kong et al., 2021;Świtaj et al., 2014;Yildirim & Kavak Budak, 2020). Previous research which examined gender differences in the experience of loneliness without consideration of internalised stigma suggested that males may be lonelier than females (Barreto et al., 2021;Maes et al., 2019;van den Broek, 2017), though other studies have reported the opposite (Jylhä, 2004;Victor & Yang, 2012). However, a recent meta-analysis found that loneliness of males and females was comparable throughout the lifespan, and that any effects of gender on participants' loneliness were generally small (Maes et al., 2019). The influence of gender reported in the current study may reflect the gender-biased sample, of which 80% identified as female.

Internalised Stigma and Mental Well-being
The second hypothesis was also supported, as internalised stigma was found to be a significant, negative predictor of mental well-being when accounting for age and gender. This aligned with the results of prior studies, which denoted significant negative correlations between internalised stigma and well-being in other stigmatised populations (Mak et al., 2007;Rose et al., 2019;Yeung et al., 2021). Notably, age was also found to be a significant, positive predictor of mental well-being, both before and after internalised stigma was considered. Combined, these results suggest that sex workers' well-being may increase with age, though internalised stigma is still associated with poorer well-being regardless of age.
No such result was reported in prior studies which examined associations between internalised stigma and well-being (Mak et al., 2007;Rose et al., 2019). However, age has been positively correlated with well-being in existing literature. For example, Abdullahi et al. (2019) found that older adults (aged 65 years and above) reported higher levels of psychological well-being than younger adults (aged 16-24 years) in Nigeria. Xing & Huang (2014) found that, within their sample of Chinese citizens, the oldest age group (aged 65 years and above) reported the highest mean score for subjective well-being. The researchers also noted that participants' mean subjective well-being scores followed an U-shape across age groups, and were lowest for participants aged between 45 and 49 years (Xing & Huang, 2014). Steptoe et al., (2015) emphasised that these findings may not be generalisable across cultures: According to an ongoing cross-national survey, there is a U-shaped relationship between evaluative well-being (i.e., life satisfaction) and age in rich, English speaking countries, with the lowest levels of well-being around ages 45-54 (Steptoe et al., 2015). However, well-being declined with age for respondents from the former Soviet Union, Eastern Europe, and Latin America, and varied little with age in sub-Saharan Africa (Steptoe et al., 2015).
The positive association between age and mental well-being found in this study may be explained by age-based differences in internalised stigma which were not explored here. For example, research has suggested that older adults are less likely than younger adults to report internalised stigma related to depression (Barney et al., 2010;Mackenzie et al., 2019a, b). However, it must be noted that age-based differences in internalised stigma appear to be variable throughout the literature: A systematic review and meta-analysis by Livingston & Boyd (2010) found no significant association between these variables. If internalised stigma indeed decreases with age, this may account for the positive association between age and well-being found in the current study. Specifically, decreased internalised stigma associated with age may allow for improved well-being, per the discovered negative association between internalised stigma and mental well-being reported here.

Loneliness and Mental Well-being
The third hypothesis was also supported, as loneliness was found to be significantly, negatively correlated with mental well-being. Further, this correlation remained significant when age was controlled for. These results suggest that greater loneliness is associated with poorer mental well-being for sex workers even outside of consideration of internalised stigma.
Again, this finding is consistent with prior literature. Golden et al. (2009) found that loneliness was associated with a lower probability of being very happy or very satisfied with life, which were used as key indices of well-being, in a sample of community-dwelling elderly people in Ireland. Peltzer & Pengpid (2019) found that, in a sample of over 30,000 participants in Indonesia, loneliness was significantly associated with low life satisfaction. Doman & Le Roux (2012) found that students with a low level of psychological well-being were likely to experience a higher degree of loneliness, and vice versa, in a sample of third-year university students in South Africa. Further, all psychological well-being subscales examined in their study (i.e., absence of anxiety, absence of depressed mood, positive well-being, self-control, general health, and vitality) were negatively correlated with loneliness (Doman & Le Roux, 2012).

Practical Implications
To our knowledge, this was the first empirical study to investigate associations between sex workers' experience of internalised stigma, loneliness, and well-being. The findings suggest that sex workers with greater internalised stigma experience greater loneliness, which may correlate with poorer mental well-being even when internalised stigma is not considered. Further, sex workers' internalised stigma may affect associations between gender and loneliness, though the nature of this effect remains unknown. Finally, although greater age was associated with better mental well-being, sex-workers' internalised stigma may still be associated with poorer mental well-being regardless of age.
Stigma, both external and internalised, has been associated with significant negative consequences for stigmatised populations. Consequences of external stigma include social isolation, emotional distress, and social inequality; as well as poorer physical health, mental health, well-being, and quality of life (Benoit et al., 2018a;Bunn et al., 2007;Gray, 2002;Green et al., 2005;Hatzenbuehler & Link, 2014;Link & Hatzenbuehler, 2016;Link & Phelan, 1995, 2001. Consequences of internalised stigma include less perceived social support, higher psychological distress, higher loneliness, and poorer well-being (Kong et al., 2021;Mak et al., 2007;Pérez-Garín et al., 2017;Rose et al., 2019;Świtaj et al., 2014;Yeung et al., 2021;Yildirim & Kavak Budak, 2020). The positive association between internalised stigma and loneliness, and the negative association between internalised stigma and well-being found in other stigmatised populations were consistent with those found in the sample of sex workers examined in this study. This is problematic considering Corrigan's (2004) theory that stigma reduces opportunities of stigmatised persons, as well as literature documenting the significant social, mental, and physical consequences of internalised stigma, loneliness, and diminished well-being. Such consequences include social isolation, lower income and rates of employment, and increased physical and mental health problems (Benoit et al., 2018a;Link & Phelan, 2001), unemployment, diminished quality of life, suicidal ideation, and risk of suicide (Bennardi et al., 2019;Benoit et al., 2018a;Corrigan, 2004;Dolan et al., 2008;Link & Phelan, 2001;Niu et al., 2020;Rumas et al., 2021).

Future Directions
Future research may benefit from examining strategies to alleviate sex workers' internalisation of external stigma to better facilitate their mental well-being and reduce loneliness. This is not to say that external stigma, such as public and structural stigma, should not also be targeted. However, due to the apparent resistance of external stigma to reduction efforts (Grittner & Walsh, 2020;Ham & Gerard, 2014;Krüsi et al., 2016;Pryor & Reeder, 2011), interventions designed to reduce sex workers' internalisation of external stigma are key until such efforts prove more efficacious. As internalised stigma has been associated with shame and diminished self-esteem, which has been demonstrated as a predictor of well-being (Corrigan, 2004;Diener & Diener 1995;Du et al., 2017), future research could also examine potential mediating effects of self-esteem on relationships between loneliness and psychological wellbeing alongside age and gender to better inform interventions. Although, a broader consideration exists in the efficacy of stigma resistance efferts and the possibility of realistically building resilience in the face of sociocultural opposition (Weitzer, 2018). Longitudinal research designs would be particularly useful in allowing more robust conclusions to be drawn from research findings. Validation of a measure of sex workers' internalised stigma would also be beneficial for use in such research.
Finally, although this paper did not differentiate between types of sex work, research suggests that various types of sex work may be associated with different levels of stigma or exposure to stigma (Benoit et al., 2018b;Klambauer, 2017;Preble et al., 2019). Given the established relationship between external and internal stigma, future research should quantify exposure to external stigma and how it may moderate levels of internalised stigma, as well as how increased exposure to external stigma may mediate relationships between internal stigma and other outcomes.
As discussed, existing theories suggest that persons and attributes are stigmatised due to perceptions of these persons or attributes as threatening social norms and population survival (including disease avoidance) (Benoit et al., 2018a;Hallgrímsdóttir et al., 2008;Phelan et al., 2008;Scambler, 2009). As such, efforts to reduce stigma against sex workers should be guided by public policies to challenge individual and institutional perceptions and portrayals of sex workers as unhygienic or amoral. This may reduce external stigma for sex workers, and consequently internalised stigma and its consequences for this population.

Limitations
This study was limited by the use of online self-reports which, though protecting participant anonymity, may have encouraged self-report bias. This, combined with the small sample size and cross-sectional research design, does not allow for causational inferences or extensive generalisability of the reported associations between sex workers' internalised stigma, loneliness, and mental well-being. The modified HIV Stigma Scale used as the measure of sex-workers' internalised stigma has also not been validated, and so its application within this study may not have similarly adequate psychometric properties as when the standard scale is used for its intended target population. Further, approximately 80% of the sample was female, thus underrepresenting the experiences of other-gendered sex workers.
The analyses conducted suggested a mediating effect of internalised stigma on associations between gender and loneliness. Although MRAs can provide information on mediating effects, future studies exploring associates of internalised stigma for sex workers should utilise research designs, including sufficient sample sizes, specifically aimed to specify mediators more robustly. In addition to age and gender, research should consider other possible mediators identified in existing literature, including; self-acceptance, relationships with others, and perceived social support (Gómez-Baya et al., 2018;Kong et al., 2021;Yeung et al., 2021).
The statistical treatment of the gender variable within this study should also be considered. As mentioned, the numerical values used to code self-reported gender were assigned arbitrarily. Despite non-binary participants being coded between those who identified as male or female (i.e., female as 1, non-binary as 2, and male as 3) for the purpose of data analysis, it could be argued that it is not conceptually possible to categorise 'non-binary' in this way, as some people who identify as non-binary may identify as on a spectrum between male and female, or as having no gender (Scandurra et al., 2019).

Conclusion
Despite the limitations, this research is an important addition to the field of research examining internalised stigma for sex workers and its associates and consequences for this population. Although further empirical research is needed to validate the results to improve generalisability, this study is an important addition to literature examining internalised stigma and its associates for sex workers; particularly within the context of the documented consequences of internalised stigma itself, as well as loneliness and diminished well-being. Understanding the associates of internalised stigma is the first step towards mitigating them, which is critically important for preventing the harmful consequences of stigmatisation for sex workers.

Funding Open Access funding enabled and organized by CAUL and its Member Institutions
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