The predictive role of photo-based behaviors on Muscle Dysmorphic Disorder symptoms and the moderation effect of body functionality appreciation among male adult Instagram users.

Introduction: Muscle Dysmorphic Disorder (MDD) is a psychological disorder mainly affecting men, characterized by extreme body dissatisfaction (Grieve, 2007). Researchers described the predictive role of photobased behaviors (PBBs) on body dissatisfaction among men (Modica, 2020; Lonergan et al., 2019). To further examine this phenomenon, the current study aimed to assess whether PBBs predict MDD symptoms. Moreover, since body functionality appreciation could buffer the negative effect of social media use on body image (Alleva & Tylka, 2021), the second aim of this study was to examine the putative moderation effect of this dimension on MDD symptoms. Method: One hundred and eighteen male Instagram users (age: M = 25.1; SD = 6.25), active in self-photosharing, completed a socio-demographic schedule, the Muscle Dysmorphic Disorder Inventory (MDDI; Santarnecchi & Dèttore, 2012), the Photo Investment Scale (PIS; Mancin et al., in preparation), the Photo Manipulation Scale – Revised (PMS-R; Gioia et al., 2021), the Body Image Control in Photos Questionnaire – Revised (BICPQ-R; Boursier & Manna, 2019), and the Functionality Appreciation Scale (FAS; Cerea et al., 2021). First, Pearson’s correlations were computed. Then, a hierarchical multiple regressions was performed utilizing the MDDI total score as a dependent variable. The PIS, the PMS-R, and the BICPQ-R total scores were entered in Step 1, the FAS total score was entered in Step 2, and body functionality appreciation x photo investment, body functionality appreciation x photo manipulation, and body functionality appreciation x body image control through photos were entered in Step 3. Results: The MDDI total score correlated with each PBBs measure and the FAS total score. In the regression, the BICPQ-R (t = 5.35; p < .001) and the PIS (t = 2.47; p = .02) total scores demonstrated a significant effect as predictors in Step 1. In Step 2, the FAS (t = -3.55; p < .001) and the BICPQ-R (t = 4.91; p < .001) total scores emerged as predictors. Finally, in Step 3, the PIS (t = 2.21; p = .03), the BICPQ-R (t = 5.02; p < .001), and the FAS (t = -3.33; p = .001) total scores showed a significant effect, as well as body functionality appreciation x photo investment interaction (t = -2.94; p = .004). Discussion: Consistent with findings on body dissatisfaction (Lonergan et al., 2019; Modica, 2020), photo management behaviors toward the body and investment related to the photo shared were predictive of MDD symptoms among male Instagram users. Supposedly, these behaviors could enhance MDD symptoms. Contrary to previous studies, photo manipulation showed a nonsignificant effect: its effect on MDD symptoms could be mediated by other PBBs. Secondly, body functionality appreciation moderated the negative associations between MDD symptoms and photo investment, underscoring the protective role of body functionality appreciation for males’ body image (Alleva & Tylka, 2021). In conclusion, interventions focused on MDD symptoms among male Instagram users should consider fostering body functionality appreciation and reducing PBBs. Moreover, improving body functionality appreciation could hamper the detrimental effect of photo investment on body image.