Content, Engagement, and Information Quality of Borderline Personality Disorder Videos on TikTok: Mixed Methods Analysis.

Background: TikTok has become a major source of mental health information, yet concerns persist regarding the quality and reliability of psychiatric content disseminated on the platform. While misinformation has been documented for several mental disorders, no study has specifically examined how borderline personality disorder (BPD) is portrayed on TikTok. Objective: This study aims to characterize TikTok content related to BPD by describing its thematic content, engagement patterns, presenter characteristics, and indicators of information quality using a mixed methods secondary analysis. Methods: This mixed methods observational study performed a secondary analysis of a previously established dataset of publicly available TikTok videos related to mental health. A total of 207 videos addressing BPD or BPD-like traits were included. Quantitative analyses summarized video characteristics, engagement metrics, presenter backgrounds, content type, intent, and authenticity indicators using descriptive statistics. Qualitative data were analyzed using reflexive thematic analysis following Braun and Clarke's methodology to identify recurrent narratives related to BPD. Results: Among the 207 included videos, 185 (89.4%) were in English and 199 (96.1%) targeted the general public. Most creators (n=124, 59.9%) did not disclose professional credentials, whereas psychiatrists (n=18, 8.7%) and psychologists (n=16, 7.7%) represented the largest identified professional groups. Seven overarching themes were identified: understanding personality disorders, treatment and management, interpersonal relationships, myths and misconceptions, co-occurring disorders, personal experiences, and diagnosis and classification. Videos focused on personal experiences generated the highest audience engagement (mean weighted likes 2389, SD 6529; favorites 333, SD 707; shares 117, SD 287), whereas treatment-focused videos demonstrated substantially lower engagement (mean weighted likes 222, SD 360; favorites 54, SD 77; shares 19, SD 40). Opinion-based or mixed-content formats predominated across most themes. Reference-based information remained limited, ranging from 0% to 33.3% depending on thematic category, while misinformation was observed across multiple themes, particularly understanding personality disorders (20/81, 24.7%) and diagnosis and classification (14/48, 29.2%). Experiential and relational narratives were substantially more prominent and engaging than evidence-based psychoeducational content. Conclusions: TikTok discourse surrounding BPD is dominated by experiential narratives that foster engagement but frequently rely on opinion-based rather than evidence-based information. Although many videos may provide validation and reduce stigma, the limited use of references and the persistence of misinformation highlight the need for the greater involvement of mental health professionals in producing accessible, accurate, and engaging digital content. To our knowledge, these findings provide the first focused overview of BPD-related content on TikTok and may inform future strategies to improve the quality of online mental health information.