The study aims to produce an economic model that illustrates how social media addiction works: when entities like Facebook, Instagram or TikTok encourage users to broaden their social network, upload more content, spend more time scrolling through content, or be exposed to content uploaded by others with the greatest influence over the individual, the risk for harmful addiction increases. The economic model will help rebut possible counter-arguments that may be put forward by these entities, such as the individual’s ability for foresee the future harm addiction causes. This is because in our model, the individual may end up with a harmful addiction even when she is rational and informed about future harm. The study shows that setting default features minimizing risk is not enough, as users subject to peer pressure by others in their network are likely to circumvent such defaults.