Muscle dysmorphia symptomatology and associated psychological features in bodybuilders and non-bodybuilder resistance trainers : A systematic review and meta-analysis

Background
Muscle dysmorphia (MD) is associated with a self-perceived lack of size and muscularity, and is characterized by a preoccupation with and pursuit of a hyper-mesomorphic body. MD symptoms may hypothetically be more prevalent in bodybuilders (BBs) than in non-bodybuilder resistance trainers (NBBRTs).

Objective
Our objective was to compare MD symptomatology in BBs versus NBBRTs and identify psychological and other characteristics associated with MD in these groups.

Methods
We searched relevant databases from earliest record to February 2015 for studies examining MD symptoms in BBs and/or NBBRTs. Included studies needed to assess MD using a psychometrically validated assessment tool. Study quality was evaluated using an adapted version of the validated Downs and Black tool. We calculated between-group standardized mean difference (effect sizes [ESs]) and 95 % confidence intervals (CIs) for each MD subscale, and performed meta-analysis when five or more studies used the same MD tool. We also extracted data describing psychological or other characteristics associated with MD.

Results
Of the 2135 studies initially identified, 31 analyzing data on 5880 participants (BBs: n = 1895, NBBRTs: n = 3523, controls: n = 462) were eligible for inclusion, though study quality was generally poor–moderate (range 7–19/22). Most participants were male (90 %). Eight different MD assessment tools were used. Meta-analysis for five studies all using the Muscle Dysmorphia Inventory (MDI) revealed there was a medium to large pooled ES for greater MD symptomatology in BBs than in NBBRTs on all MDI subscales (ES 0.53–1.12; p ≤ 0.01). Competitive BBs scored higher than non-competitive BBs (ES 1.21, 95 % CI 0.82–1.60; p < 0.001). MD symptoms were associated with anxiety (r 0.32–0.42; p ≤ 0.01), social physique anxiety (r 0.26–0.75; p < 0.01), depression (r 0.23–0.53; p ≤ 0.01), neuroticism (r 0.38; p < 0.001), and perfectionism (r 0.35; p < 0.05) and were inversely associated with self-concept (r –0.32 to –0.36; p < 0.01) and self-esteem (r –0.42 to –0.47; p < 0.01).

Conclusions
MD symptomatology was greater in BBs than in NBBRTs. Anxiety and social physique anxiety, depression, neuroticism, and perfectionism were positively associated with MD, while self-concept and self-esteem were negatively associated. It remains unclear whether these characteristics are exacerbated by bodybuilding, or whether individuals with these characteristics are attracted to the bodybuilding context.