Multiple sclerosis (MS) is associated with a psychosocial burden, suggesting that social cognition could be impaired in patients with this disease. Using video-based testing, Pöttgen et al. compared 'theory of mind' (ToM)—the ability to recognise mental states and attribute them to oneself and others—in 45 patients with MS and 45 control individuals. The MS group showed significant impairments in ToM, even in early-stage disease. The greatest deficit was observed in identification of emotions, which could contribute to the psychosocial burden of MS.