He suffers from body dysmorphia, always believing his muscles are underdeveloped despite being actually quite muscular.

dysmorphia 是由前缀 dys-（表示“异常的、困难的”）和希腊词根 morphia（“形态、形状”）组成的复合词，字面意思是“形态异常”。在心理学领域特指对身体形象的扭曲认知，即“体象障碍”。