To our knowledge, this is the first study investigating the specificity and vividness of disgust-related AMs and future events in both AN and binge-type EDs (BN or BED) compared to HC. Surprisingly, our first hypothesis, which predicted that participants with EDs would exhibit more difficulties in recalling specific AMs and constructing specific future events compared to HCs was not supported, as the specificity of AMs and EFTs was comparable between groups. Also, the specificity of recalled AMs and constructed future events did not vary depending on the valence of the cue (negative/moral disgust-relevant, or neutral). Future events primed by neutral cues were rated as more vivid by the control group compared to those induced by negative cues. Our second hypothesis predicted that the specificity of EFTs would be predicted by AM specificity, which was confirmed in all groups. The last hypothesis which predicted that higher scores in POBS and TQ-R would predict more specific and vivid AMs and EFTs primed by negative/moral disgust-relevant cues in the clinical group but not in the control group, which was partially confirmed. Both victimisation experiences contributed to models only for AM and EFT vividness ratings, but not specificity.
Previous research has employed a range of negative cue words, both general and ED specific. In the present study, we focused on negative cues related to disgust, specifically moral disgust - disgust directed at behaviours, individuals, or ideas that violate one’s moral, ethical, or social values. The manipulation check in the present study confirmed that all groups reported greater feelings of disgust towards AMs, and EFTs primed by negative/moral disgust-relevant cues than those primed by neutral cues. Furthermore, despite comparable disgust sensitivity scores across all groups, we observed significant group differences in ratings of disgust in the AMT/EFT-T tasks between the ED groups and HC. In comparison with controls, participants with BN/BED reported greater disgust towards both AMs and EFTs, while participants with AN reported greater disgust towards only EFTs. These findings suggest that disgust elicited by memories/future events is greater in people with EDs compared to HCs. These results corroborate previous findings of increased food-specific disgust and self-disgust in people with EDs [20, 21].
A meta-analysis by Barry et al. [7] suggests that deficiencies in AM retrieval is a transdiagnostic feature across various mental illnesses. Reductions in memory specificity in response to emotional cue words have been observed in people with AN [8, 11, 15, 18]. A study by Keeler et al. [13] found that participants with AN recalled less specific AMs compared to controls, regardless of cue valence. However, our findings did not indicate such an overgeneral memory effect (OGM) in either the AN or the BN/BED groups compared to controls. This conflicting result may be due to differences in sociodemographic and clinical variables. For instance, participants with AN in the recent study by Keeler et al. [13] had a lower mean BMI (16.02 kg/m2) than those in this study (16.98 kg/m2; mean BMI difference = 0.96 kg/m2). Similarly, samples in studies by Huber et al. [12] and Bomba et al. [8] had lower mean BMIs: 14.7 kg/m2 and 15.5 kg/m2, respectively. This suggests that the cohort in the present study may have been less physically compromised. In a meta-analysis of cognitive function in AN, BMI has been found to moderate cognitive performance with higher BMI resulting in smaller differences compared to controls, especially for the cognitive domain of memory [3].
In this study, there were elevated depression scores in people with AN and in people with BN/BED compared to the healthy control group (see Table 2) which is in line with previous research [45]. However, both clinical groups in our study had lower (mild) DASS scores than in Keeler et al. [13] (moderate scores), indicating lower levels of general psychopathology. Indeed, Keeler et al. [13] controlled for the effect of DASS-Depression scores, and the observed group effects on memory specificity were found to be non-significant, in contrast with the current evidence indicating that the OGM effect exists independently of depressiveness [9, 11, 15]. The lower severity in terms of ED psychopathology might explain why we did not detect reduced memory specificity in our ED groups compared to controls, and particularly for the AN group. It is still unclear whether deficiencies in AM are dependent upon comorbid symptoms such as depression.
The findings in the present study also indicated that there was no significant difference in the ability to produce specific EFTs between groups, which is unsurprising given that AM specificity predicted EFT specificity in all groups, in keeping with the second hypothesis based on the Constructive Episodic Simulation hypothesis [19], and AM specificity was unaffected.
Interestingly, we also found that HC group reported more vivid EFTs in response neutral cues compared to negative ones. This evidence may support the phenomenon known as the positivity bias, which refers to the idea that people more likely to recall positive experiences and avoid negative ones [46]. As the HC group were not expected to have compromised AM or EFT, it makes sense that this group would demonstrate a positivity bias in future simulation. Imagining the future plays an important role in psychological well-being [47]. In the control group, generating less vivid future events to negative cues may be considered vital in maintaining positive views of themselves and their personal future, constituting a self-protective mechanism. This difference in vividness ratings between negative and neutral cues seen in HCs was not seen in EDs.
Additionally, our regression analysis findings provide evidence for the contribution of childhood teasing and betrayal sensitivity on the ability to generate more vivid AMs and future events in response to cues representing negative life events violating personal, social, or moral values. This association was found only in the ED group. Both teasing and bullying have been found to have similar effect on increasing the risk for disordered eating behaviours [48]. However, to the best of our knowledge, this is the first study to examine the role of betrayal sensitivity in the ED population. Betrayal sensitivity has been reported to influence behaviour alongside expectations of trustworthiness [49], occurring transdiagnostically [50]. These victimisation experiences are more salient in one’s mind and therefore more vivid and may be more salient to people with EDs with a higher impact on imagined negative future events [51] given the evidence that they frequently report a variety of fears such as fear of food, weight gain, loss of control, and judgment by others [52, 53].
Clinical implications
These findings suggest that incorporating mental imagery techniques (e.g., imaginal exposure, [54] and imagery rescripting (IR); [55, 56]) into psychological interventions may be a tool for reducing the vividness and emotional intensity of distressing memories or future events associated with historical betrayal or teasing experiences. IR could potentially facilitate the development of new meanings to those past and/or anticipated victimisation experiences. It could also promote greater self-image integration through receiving care, which was reported as being the most important element of change in a study by Bosch and Arntz [57].
Strengths and limitations of the present study
Study strengths include that the sample included individuals with binge-type EDs. Another strength is that we used a PPI group to generate salient negative cues to address moral disgust. There are however several limitations to this study. First, the findings should be regarded as preliminary due to a relatively small sample size and cross-sectional nature of the study. Ideally, it would have been even better to have a separate BN and BED group, but this was not possible because of recruitment challenges. Second, to verify the clinical significance of ED symptomatology, self-report questionnaires were used rather than structured interviews, and BMI measures were based on self-reported weight and height and therefore could not be verified by researchers. Third, the remote administration of the tasks might be considered another limitation since the environment in which participants completed the tasks might be more variable. Lastly, ethnic/racial, and age-related differences between groups were observed, although this was controlled for in all analyses. It would be preferable to have a larger comparison group in order to match the diverse characteristics of the clinical groups.
Future research
To make our findings more generalisable, research within more diverse communities and from various continents is needed [58]. More studies following a more standardised methodology is required to better delineate the effects of illness parameters (i.e., BMI, illness duration, depression level, social adjustment) on AM recall and EFT construction. Recruiting samples from one particular treatment modalities, for example, inpatient units, would be of benefit. AMs, future events and their interpretation might change during psychological therapy. Thus, the influence of psychotherapy on disgust elicited by memories/future events and the perception of trauma and betrayal might be a further area for research. Qualitative research exploring AMs and future events produced in response to disgust-relevant cues would be invaluable for clinical practice to understand the content and nature of memories/future events rather than only a single metric of specificity. Finally, longitudinal cohort studies starting from school age are needed to establish causal relationships between experiences of teasing, betrayal (actual and/or perceived), relevant memories/future events and the development of ED-specific and general psychopathology.