We investigated a unique way in which adolescent peer influence occurs on social media. We developed a novel fMRI paradigm to simulate the popular social photo-sharing tool Instagram, and measured adolescents’ behavioral and neural responses to “Likes,” a quantifiable form of social endorsement and potential source of peer influence. Adolescents underwent fMRI while viewing photographs ostensibly submitted to Instagram. Adolescents were more likely to Like photos depicted with many Likes and refrain from Liking photos with few Likes – indicating the influence of virtual peer endorsement, a finding that held for both neutral photos and photos of risky behaviors (e.g., drinking, smoking). Viewing photographs with many (vs. few) Likes was associated with greater activity in neural regions implicated in reward processing, social cognition, imitation, and attention. Furthermore, when adolescents viewed risky (vs. non-risky) photographs, activation in the cognitive control network decreased. These findings highlight possible mechanisms underlying peer influence during adolescence.

BACKGROUND Pruritic urticarial papules and plaques of pregnancy (PUPPP) is the most commonly diagnosed pregnancy-specific dermatosis. It presents with intense pruritus and can be difficult to manage which encourages mothers to look to social media for camaraderie and advice. OBJECTIVE This study seeks to characterize the sources and thematic content of Instagram posts in order to define influential groups of users. Our goal is to determine the current status of online discourse surrounding PUPPP and elucidate any potential space for healthcare provider intervention. METHODS Three hashtag categories were selected (#PUPPP, #PUPPPs and #PUPPPrash) and the top public posts from each were analyzed and organized by source and by thematic content. Number of likes and comments were also recorded. RESULTS Of the top 150 posts in each hashtag category, only 428 posts were eligible in total for this analysis. A majority (73.8%) of posts were created by mothers who experienced PUPPP. These posts were testimonial accounts in nature. A small fraction of posts (3.3%) were generated by physician accounts. Posts from blogs with extensive followings garnered the most attention in the form of likes and comments. CONCLUSIONS Mothers experiencing PUPPP comprised the majority of accounts posting under the hashtags selected. The most common themes included pictures of the rash and personal testimonies. Posts under blog posts received the most likes and comments on average. There is a space for physician and healthcare specialists to improve their social media presence when it comes to discourse surrounding PUPPP. Patients are seeking out communities on social media, like Instagram, in order to have questions answered and get advice on management. Accounts with large followings tend to have more likes and more comments which encourages information dissemination and awareness.