<p>Research suggests some individuals with progressive supranuclear palsy (PSP) have socioemotional deficits, typically characterized as reduced emotion recognition, difficulty with perspective taking, and increased apathy. However, the variability of these deficits across individuals and the pattern of impairments across the spectrum of social cognition have not been quantified in larger samples. The present study used multiple face-to-face and informant-based social cognition, neuropsychiatry, and personality measures to identify socioemotional changes occurring as a result of PSP. Data were collected from 287 individuals: 113 with early-stage PSP (Clinical Dementia Rating scale global score &lt; 2) and 174 older healthy controls (HC). Though there was a high degree of individual variability, on average those with PSP had a pervasive pattern of deficits across tests of social cognition compared to HC, including emotion reading, social inferencing, theory of mind, and identifying and applying social behavior rules. Worse neuropsychiatric functioning was reported on both self- and informant-report measures, including increased depression, apathy, and anxiety. Changes in personality, including reduced conscientiousness, openness, and extraversion, from pre-morbid to current presentation were also found. Our analyses revealed that the social withdrawal typical of PSP is not simply a reflection of apathy or emotion reading deficits, but is directly correlated with the degree of the patient’s depression and self-reported sense of hopelessness. These results reveal more clinically significant socioemotional deficits and personality shifts in early-stage PSP than are generally recognized, and suggest face-to-face testing and informant reports of socioemotional functioning may provide critically important information to guide clinical care.</p>