Social cognition in female adults with Anorexia Nervosa: A systematic review

Highlights

• Social cognitive difficulties are common in female adults with Anorexia Nervosa.

• Empathy is intact while processing of own emotions in oneself is disrupted.

• Findings in emotion recognition and emotional Theory of Mind are inconsistent.

• The nature of the task influenced results in cognitive ToM and social perception.

• Research on social cognition is predominantly of moderate quality.

Abstract

Deficits in interpersonal and social functioning are well established in females with Anorexia Nervosa (AN), and are thought to be key features involved in the onset and maintenance of the disease. Growing literature suggests these may be attributed to poor social cognitive processes. This systematic review evaluates whether differences in social cognition exist in adult females with AN. A total of 32 studies that compared females with AN against a healthy control group using social cognitive measures and/or questionnaires were analysed. The majority of studies were deemed to have a low or moderate risk of bias. Overall, empathy appears to be intact in AN, however greater emotion regulation difficulties, elevated alexithymia and reduced emotional awareness are evident in AN. Findings relating to emotion recognition and emotional Theory of Mind were inconsistent. The nature of the task appeared to influence the domains of cognitive ToM and social perception, warranting further research. These findings are discussed within the broader context of social cognitive models and AN rehabilitation.

Introduction

Current statistics place the national point prevalence of eating disorders (ED) for those aged 15 years and over between 4–16 % of the Australian population, with females accounting for 95 % of all hospitalisations (AIHW, 2018). Anorexia Nervosa (AN), specifically, is a psychiatric illness characterised by the failure to maintain body weight due to a restrictive diet and poor nutrition, compulsive and/or excessive exercise, and fear of weight gain. Sufferers typically experience perceptual distortions in their weight and body shape, resulting in extreme weight loss (American Psychiatric Association; APA, 2013). Though point prevalence numbers of AN are reportedly low, occurring in less than 1 % of the Australian population (Hay et al., 2015), 1–4 % of European women, 1.05 % of the Chinese population, and 0.43 % of the Japanese population (Hoek, 2016), it has the highest mortality rate of all psychiatric disorders, with suicidality common (Arcelus et al., 2011). Onset for AN commonly occurs in childhood and adolescence (APA, 2013) and typically it is a while before the individual’s family are aware of the seriousness of the disease. AN is an insidious illness, tending towards a prolonged course, extending for more than twenty years in more than 50 % of sufferers (Fichter et al., 2017). The illness also has a high risk of relapse within the first year following intervention (Khalsa et al., 2017) making treatment difficult and recovery slow.

Two subtypes of AN are specified; the restricting subtype (AN-R) and the Binge-eating/Purging subtype (AN-BP). In AN-R, individuals starve themselves through food, liquid, and calorie restriction. In AN-BP, the person engages in binge and purge behaviours including self-induced vomiting and/or the use of laxatives and diuretics. However, studies have found high crossover rates between the two subtypes, and suggest the AN-R subtype may represent a phase in the disease as opposed to a unique subtype (APA, 2013; Eddy et al., 2002; Gleaves et al., 2000).

The aetiology of AN is complex, with a variety of risk factors likely compounding genetic susceptibility (see Connan et al., 2003; Karwautz et al., 2001; Lindberg and Hjern, 2003 for reviews). In adults with AN, pharmacological and psychological interventions (e.g., family-based therapy (FBT), cognitive behavioural therapy (CBT)) appear to have limited efficacy on treatment and recovery, given the disease is more likely to be enduring and resistant to change at this stage of life (Fairburn, 2005). For example, a meta-analysis of randomised controlled trials of these specialised treatments (Murray et al., 2019), did not find them superior relative to comparator treatments (such as placebos, waitlists, and psychoeducation) in achieving weight restoration nor recovery of psychological symptoms at follow up. Indeed, the authors suggest that a plateau in the efficacy of treating AN has been reached. This is disconcerting considering the adverse impacts AN has on biological, emotional, and psychosocial outcomes. For example, suicidality is closely associated with AN and appears related to poor emotion regulation skills (Goldstein and Gvion, 2019). Compared to healthy controls (HC), those experiencing AN are also less likely to secure employment (Wentz et al., 2009), are more likely to live alone (Löwe et al., 2001), and report experiencing a lower quality of life (Kane et al., 2017). The limited efficacy of current major interventions for AN (such as CBT and FBT) may indicate that the theoretical models underpinning these treatments do not fully explain the pathology of AN. This highlights the need for a better understanding of the emotional and psychosocial mechanisms underpinning the disorder. Indeed, there is growing evidence to suggest severe interpersonal deficits for those suffering with AN which may indicate a role for social cog these interpersonal difficulties can lead to problems forming therapeutic alliances crucial for effective treat nition in AN aetiology.

Poorer social functioning in AN is well established and often results in reduced social networks and social anhedonia (Harrison et al., 2014). Interpersonal difficulties are prominent and are theorised to contribute to the maintenance of the disease. Schmidt and Treasure’s (2006) cognitive-interpersonal maintenance model for AN proposes that AN is maintained by interpersonal factors; including both complimentary and negative reactions of people around them. Complimentary comments in the early phase of AN regarding weight loss may serve as a reinforcer for calorie restriction. Conversely, the confronting physical presentation that develops as the disease progresses, elicits negative and concerned reactions in the sufferer’s social network, which can lead the AN person to avoid these relationships. This is further complicated by intrapersonal factors of the disease, namely, its egosyntonic nature, whereby sufferers do not accept their condition as an ‘illness’ and view the condition as serving a positive purpose (Treasure et al., 2020). This starkly contrasts the deep concern of those around them, and can lead the AN individual to feel increasingly criticised and exposed to negative emotions (Schmidt and Treasure, 2006) and thus leading to greater social withdrawal and isolation.

As such, these interpersonal difficulties can lead to problems forming therapeutic alliances crucial for effective treatment (Zucker et al., 2007). McIntosh et al. (2005) explored the effectiveness of CBT and interpersonal psychotherapy in treating AN by comparing it to a non-specific supportive clinical management. Interpersonal psychotherapy was found to be the least successful in treating patients with AN, suggesting problems with social information processing. Some literature suggests these social difficulties may be a direct result of the illness (i.e., starvation), particularly given that recovered AN patients perform comparably to HC and superior to currently ill samples on measures of emotional processing (Oldershaw et al., 2012). However, women with a diagnosis of AN experience higher levels of loneliness, shyness, and inferiority in their adolescence, prior to AN onset (Troop and Bifulco, 2002), suggesting social difficulties may precede, and potentially be causal, to the AN diagnosis. Regardless, poor interpersonal and social functioning are prominent in AN. Indeed, in their revised maintenance model for AN, Treasure and Schmidt (2013) summarise evidence for cognitive and socio-emotional factors of the disease, including attentional bias towards negative facial expressions, difficulties in recognising the emotions and the intentions of others, and difficulties with both emotional expressiveness and understanding one’s own emotions. This model provides a foundation for the potential role of poor social cognitive processes in AN. However, despite bodies of literature on how social cognition underpins social functioning in other psychiatric (e.g., schizophrenia), neuropsychological (e.g., dementia), and neurodevelopmental (e.g., Autism Spectrum Disorder; ASD) disorders, research has only recently emerged on social cognition in AN.

Social cognition refers to the mental processes governing one’s ability to interpret and respond to social information within their environment (Bora and Köse, 2016). It guides social behaviour through understanding the thoughts, feelings, and intentions of others (Dejong et al., 2013) and underlies our capacity to form relationships. It is a multi-dimensional construct that is viewed as a distinct function from other neurocognitive domains (Fett et al., 2011) and as such, various measures exist to assess its many facets. A consensus meeting by the National Institute of Mental Health (NIMH) for social cognition in schizophrenia provided a cohesive definition of social cognition (Green et al., 2008). The authors propose a model for defining the various aspects of social cognition, separated into five areas: 1) Theory of Mind (ToM); also known as ‘mentalising’ or ‘mind reading’, is the ability to attribute mental states to others via both facial affect and perspective taking; 2) social perception; the ability to form an understanding of social roles, people, and relationships, based on a collection of nonverbal, verbal, and physical cues; 3) social knowledge; the capacity to adapt ones behaviour to the environment through understanding the rules and expectations for the social context; 4) attributional bias; the inferences made when individuals evaluate the cause of certain events, and; 5) emotional processing; a broad term for the capacity to identify, understand, facilitate, and regulate emotions.

As highly social beings, these skills are essential for functioning in a complex society where empathy and understanding the needs of others forms the basis of a thriving community. Furthermore, there is well established literature which asserts social cognition strongly predicts an individual’s behavioural and functional outcomes. A meta-analysis by Fett et al. (2011) found social cognition to be more strongly associated with community functioning (that is, interpersonal relationships, occupational functioning, and utilisation of community resources) than any other cognitive domain in patients with schizophrenia. This is highly relevant given the research which suggests AN patients also demonstrate difficulties across various areas of social cognition. For example, a meta-analysis of 15 studies of ED patients (Bora and Köse, 2016) found significant impairments in cognitive ToM, also known as perspective taking, in those with AN, with those in the acute stage demonstrating considerably greater impairments (d = 0.67). Furthermore, cognitive ToM was a unique deficit to AN and was not observed in other ED. This ability was measured by participants’ mental state reasoning towards a series of pictures and stories whereby they have to understand the intentions of others. Importantly, impairments in ToM were still evident in AN individuals post-recovery (d = 0.35). Furthermore, a very recent meta-analysis comparing cognitive and affective empathy found AN patients demonstrated lower cognitive empathy ability to HC, whilst overall empathy levels and affective empathy did not differ (Kerr-Gaffney et al., 2019).

Whilst these previous meta-analyses highlighted that ToM and cognitive empathy differed in AN, other areas of functioning that fall under the broad umbrella of social cognition have received considerably less attention in terms of review and synthesis. No manuscripts to date have examined and synthesised the literature surrounding social perception, social knowledge, attributional bias, and emotional processing in adult AN patients. This is an important consideration, as distinct patterns of social cognitive deficits may serve as important diagnostic markers for AN and inform treatment strategies to promote positive social functioning.

The aim of this systematic review was to synthesise the evidence relating to social cognition in patients with AN to better understand the socioemotional and cognitive mechanisms underpinning the disorder. We anticipate this information will subsequently inform treatment options for AN by contributing to the theoretical models underpinning the treatments used in AN. In addition, we anticipate this review will provide support for, and add further insight into the current models that integrate social cognition as a maintenance factor for AN. The following objectives were addressed:

• Explore whether social cognitive processes differ in adults with AN relative to HC.

• Examine which measures have been used to assess the many dimensions of social cognition in AN.

• Assess the quality of the studies within the review. A risk of bias assessment was included in order to rate the methodology of each study to assist interpreting the clinical relevance of the results.