Friends, lovers, and companions: A systematic scoping review of empirical evidence on human-AI relationships

The rapid popularization of artificial intelligence (AI) conversational agents (CAs) has sparked growing scientific and public interest in the nature and consequences of human-AI relationships. However, what we empirically know about these relationships and their social effects remains scattered. This scoping review consolidates the study designs and methodological approaches in the current literature on human-AI relationships, as well as the AI systems and populations studied, their focus areas, and key empirical findings. Following JBI methodology, three databases (Scopus, PubMed, PsycINFO) were searched in September 2025, supplemented by Google Scholar, arXiv, and reference list screening to maximize coverage. Of the 2,280 papers initially identified, 89 met the inclusion criteria and were independently extracted by two reviewers. The literature is mostly characterized by qualitative and correlational designs, with many studies focusing on the AI companion platform Replika. Studies were organized around three thematic orientations: mechanisms underlying engagement, relational experiences with CAs, and psychosocial effects. Qualitative data suggest that loneliness was a frequently reported motivator for CA use, and users often reported perceived benefits, including reduced loneliness, emotional support, and improved social confidence, as well as positive erotic and relational experiences. However, quantitative experimental and longitudinal evidence remains limited and mixed, and the effects of AI companionship appear contingent on individual characteristics, contextual conditions, and patterns of use rather than being uniform across users. Longitudinal experimental research, greater diversity in the platforms and populations investigated, and regular systematic syntheses of evidence are needed to advance science on human-AI relationships.