Body Dysmorphic Disorder (BDD) is characterized by excessive preoccupation with one or more subjective flaws in appearance and associated distress or impairment in daily life (American Psychiatric Association, 2013). According to cognitive-behavioral BDD models (Veale & Neziroglu, 2010; Wilhelm et al., 2013) and experimental studies (Barnier & Collison, 2019; Kollei & Martin, 2014; Waldorf et al., 2019), looking into a mirror elicits dysfunctional processing of one’s own appearance. As in other body image disorders, mirror checking and mirror avoidance are common safety behaviors in BDD (Naumann et al., 2022). Mirror checking serves as a behavioral response to uncertainty about appearance and is motivated by the hope to be less dissatisfied with the appearance, at the same time it increases selective attention to the disliked body part(s) (Veale & Riley, 2001). Additionally, it is not uncommon for those affected to also avoid, either completely or partially, situations in which they are confronted with their own appearance and thus with the associated aversive feelings. This also strengthens dysfunctional processing of the self and thus selective attention (Veale & Neziroglu, 2010). Selective attention in BDD refers to threatening stimuli associated with rejection or judgment (Johnson et al., 2018), as well as disorder-related stimuli such as body parts.

Kollei and Martin (2014) found that individuals with BDD expressed more body-related and more negative cognitions than participants who were either in good health or suffering from a major depression when confronted with their bodies in the mirror. On the day after the exposure, participants with BDD reported more post-event processing than controls. The results on post-event processing were supported by Schoenenberg and Martin (2022) in people with elevated BDD concern. Neziroglu and colleagues (2010) investigated mirror gazing in BDD and healthy participants at one-minute intervals. The levels of fear and disgust were higher in the BDD group, but decreased significantly over time.

Satisfaction with one’s own body or appearance represents the cognitive-evaluative component of body image (Cash, 2012). In a study by Waldorf et al. (2019), men with the BDD subtype muscle dysmorphia had a generally lower level of state body satisfaction and higher negative affect scores than weight-trained or non-weight-trained controls. When confronted with images of their own body, participants in all the groups responded with a lower level of body satisfaction, but negative affect increased only in the muscle dysmorphia group. No study has investigated state body satisfaction in women with elevated BDD symptoms in the context of mirror exposure so far. For this reason, we aimed to assess state body satisfaction pre and post isolated mirror exposure. We hypothesized the following:

Hypothesis I (BDD group effect): Individuals with distinct BDD symptoms express overall lower state body satisfaction (H1a) and stronger negative affect (H1b) in the context of mirror exposure than individuals with low or no BDD symptoms. Furthermore, individuals with distinct BDD symptoms experience more post-event processing (H1c) about the exposure the following day than a group with low or no BDD symptoms.

In the treatment of BDD, mirror exposure serves to correct attentional and evaluative biases (Veale & Neziroglu, 2010; Wilhelm et al., 2013). Typically, individuals are asked to describe their body in, e.g., a neutral, or non-judgmental way when confronted with their body image in the mirror (Griffen et al., 2018; Schoenenberg & Martin, 2022). Compared to short mirror viewing, it is common to guide the attention to different body parts during mirror exposure to counteract poor global processing and to train finding a less judgmental way of describing the body. It takes longer than short viewing or checking and follows a different approach which is why some manuals prefer the term “mirror retraining” (Wilhelm et al., 2013). Even though mirror exposure or retraining is part of cognitive behavioral treatment manuals, no study has investigated its isolated effect on individuals with BDD (Griffen et al., 2018). Due to the experimental character of the present study the term “mirror exposure” will be used in the following even though we did apply a typical retaining rationale including guidance through the body parts, with instructions to observe upcoming thoughts and emotions and to use a neutral description of the perceived body parts.

Reviews of research on eating disorders summarized the positive effects of repeated video and mirror exposure (Butler & Heimberg, 2020). The few studies on body image exposure in samples with weight-related body dissatisfaction examining within and between sessions effects in detail tend to support between-session effects (Díaz-Ferrer et al., 2017; Moreno-Domínguez et al., 2012). To our knowledge, the effects of mirror exposure within and between sessions with respect to body image evaluations and affective responses in persons with distinct BDD symptoms have not yet been studied. Therefore, we tested the following hypotheses:

Hypothesis II (within-session time effect): At the end of a mirror exposure session, state body satisfaction is higher (H2a) and negative affect is lower (H2b) in comparison to at the beginning of the session.

Hypothesis III (between-session effect): In a second mirror exposure session, body satisfaction is higher (H3a); negative affect is lower (H3b) and post-event processing is lower (H3c) compared to in the first session.

As a third goal, this study aimed to uncover the potentially destructive role of post-event processing in maintaining the disorder. This mechanism is well-known and well-studied for social anxiety (e.g., Fehm et al., 2008; Rachman et al., 2000). It refers to a negatively biased way of reprocessing a previous difficult event and is considered a special form of rumination. Negative distorted post-processing could lead to change in the memorized experience and could interfere with the correction of one's own expectations. If post-event processing contributes to maintenance of appearance-related concerns, stronger post-event processing after a first mirror exposure should predict a poorer body image at the onset of the second session. This could also be of therapeutic relevance, as the barrier to so far avoided mirror exposure could be higher with more pronounced post-event processing and could possibly even risk dropout. Accordingly, we investigated the following hypothesis:

Hypothesis IV (model prediction): Post-event processing about the first mirror exposure predicts lower state body satisfaction (H4a) and higher negative affect (H4b) at the beginning of the second exposure.

To test these hypotheses, we invited individuals with body dysmorphic symptoms and a group without (or with only a low level) of BDD symptoms to participate in the study. All participants took part in two guided mirror exposure sessions separated by a one-week interval. The exposure procedure was standardized and similar to mirror exposure in BDD treatment. No additional intervention components were provided to the study participants.

The present study was the first to investigate repeated guided mirror exposure in BDD-symptomatic women as a standalone intervention. We aimed to examine effects within one session and between two sessions of mirror exposure.

As assumed, body image exposure was related to a more negative cognitive evaluation, here, state body satisfaction and dysfunctional rumination about the exposure, which is called post-event processing, in individuals with higher BDD symptoms than in those with fewer or no symptoms. Descriptively, both groups experienced tension and shame with the highest intensity, while the levels of anxiety and sadness were overall lower. A comparison of the two groups showed that shame and sadness were elevated only in individuals with distinct BDD symptoms. Sadness was found to be higher for individuals with BDD in the first exposure session only. Unfortunately, we did not capture the level of disgust in this study. Earlier studies have identified the experience of disgust to be relevant during mirror exposure (Kollei & Martin, 2014; Neziroglu et al., 2010).

The results on affects during exposure are in line with the findings of previous studies which found sadness to be higher in individuals with BDD (Kollei & Martin, 2014; Schoenenberg & Martin, 2022) and reported higher levels of shame in BDD positive participants (Schoenenberg & Martin, 2022). Overall, our results indicate that anxiety is not the main affect in this body confrontation paradigm. Shame has been discussed as a key affect in BDD in previous work (Malcolm et al., 2021). Addressing and changing the experience of shame during mirror exposure may be a crucial mechanism that needs further investigation.

The second research question addressed changes over time within one exposure session. State body satisfaction did not increase, but decreased significantly from pre to post in each session. This implies that state body satisfaction deteriorated with the exposure interventions, even though we applied a relatively long exposure time and a neutral description of body parts. Consistent with this, a previous study found increased or unchanged discomfort with one’s body in women who were dissatisfied with their body at the end of a guided mirror exposure (Díaz-Ferrer et al., 2017; Moreno-Domínguez et al., 2012). Affects did not change significantly from the first full-body view at the beginning of the session (ExB) to the full-body view at the end (ExE). It is possible that the participants still felt affected at this point due to the exposure with a difficult stimulus. The intensity of negative affect was significantly lower when exposure was terminated, but negative affects do not seem to decrease during this type of guided exposure. A clear habituation approach without directing attention to the various parts of the body may have led to a greater change in affect from the beginning to the end of the intervention, as it has been found in a study by Díaz-Ferrer et al. (2017) who investigated pure exposure. However, due to the attentional bias associated with body image disorders (Johnson et al., 2018), such an approach would tend to promote a dysfunctional approach to self-image (Veale & Riley, 2001). We did not assess affect while the subjects were viewing their most aversive body part(s). Negative affect might have been increased during this period. In addition, the affect ratings were communicated to the examiner verbally, which may have had an impact on their extend, particularly in the case of shame.

Nevertheless, shame seemed to be more relevant than anxiety during the mirror viewing, as pointed out earlier. The experience of shame is closely related to self-evaluation or evaluation by others (Goss & Allan, 2009). Due to this relationship, changes in shame experience may follow from cognitive changes (e. g. the realization after a mirror exposure that one did not hate the whole body). Consequently, strong affect changes within one session may not be the decisive mechanism for successful mirror exposure and long-term changes in shame experience.

The comparison of the exposure sessions revealed that state body satisfaction was significantly higher and negative affects were significantly lower in the second session, indicating the positive effect of the repeated exposure intervention. An increase of body satisfaction between sessions was also reported in a study of women with bulimic symptoms (Díaz-Ferrer et al., 2015) and later in a study of body dissatisfied and subclinical eating disordered women (Díaz-Ferrer et al., 2017), both studies used pure and guided exposure. In line with our results, Trentowska et al. (2013) reported a reduction of subjective distress and negative affect between sessions using a similar approach to that used in this study, including guiding attention and a neutral description of the various body parts. A study by Tanck et al. (2021) found positive between-session effects among healthy women in terms of body satisfaction and negative affect for both types of instructions – positive or negative verbalizations – of body parts during exposure. Taken together, all of these findings imply the importance of repeated mirror exposure in clinical practice even though the possible different underlying mechanisms have not yet been clarified.

Another positive effect of repeated mirror exposure was the lower level of post-event processing after the second session. Experiencing the second exposure as less aversive could have reduced engagement in ruminative processes afterwards. Furthermore, higher post-event processing after the first exposure predicted higher tension, shame, sadness, and fear when individuals were initially confronted with their body in the mirror at the second exposure. Addressing dysfunctional post-processing and providing more helpful ways to deal with uncertainty could therefore be very important interventions for clinical practice. Due to the potential impact on memory and associated expectations, addressing post-event processing could possibly amplify the positive effects or reduce negative effects due to dysfunctional processing between exposure sessions.

In sum, repeated mirror exposure may improve important processes, and post-event possessing may be an indicator for successful coping or learning. However, this assumption needs further scientific investigation. Mechanisms of mirror exposure for eating disorders have been discussed by Naumann et al. (2022). They proposed cognitive restructuring and related changes in cognitive biases as plausible explanations. In this study, we did not induce any specific expectations regarding the effects of the exposure and did not examine the expectations of participants. Therefore, we cannot accurately assess the role of expectations in this context. Since current research on anxiety disorders point to the important role of changes in expectations during exposure and the exposure-related learning rate (Pittig et al., 2023), it would be very important to investigate the role of expectation changes and learning rate through mirror exposure in the future. We should incorporate the assessment of expectations prior to the intervention and understand how expectation may influence the results.

Some limitations of the present study need to be considered when interpreting the results. One main limitation is the not fully clinical sample and the lack of confirmation of the clinical diagnosis by means of a clinical interview. Individuals with BDD symptoms who strongly avoid mirrors probably did not take part in the study. Differential effects may become apparent in comparison to a fully clinical sample. We investigated women only, even though there is a substantial group of males with BDD. The internal description of appearance during exposure may have reduced the intensity of affect intensity. Although participants said they were able to follow the instructions, we cannot know, i.e., whether they shifted their visual attention to different body parts. In addition, possibly ongoing safety behavior could have been better recognized by a therapist guiding the participant. We focused on assessing in-session and short-term between-session effects. Hence, further investigation of the stability of the improvements is required. It is of interest to see whether further sessions, including repetition as homework, contribute to an even greater change in individuals with BDD.