This presentation brings together two projects that explore how artificial intelligence, particularly conversational agents and social bots, shapes human interaction in two important domains: mental health and political discourse. One project investigates the role of AI conversational agents in supporting individuals struggling with depression, while the other examines the impact of social bots and human agents in navigating political discussion in online communities. From digital companions that reduce mental health stigma to bots that provoke or soften political disagreement, the talk uncovers how AI can influence cognitive, emotional, and behavioral outcomes, especially in emotionally charged or socially sensitive contexts.