Mental health discussions on social media reveal profound gaps between clinical understanding and public perception, particularly around complex psychiatric conditions. These knowledge gaps could significantly impact how young adults navigate their mental health journey and seek appropriate care. Canadian researchers analyzed over 25,000 comments from 141 TikTok videos about borderline personality disorder, uncovering widespread diagnostic confusion among viewers. The analysis revealed that users frequently conflated BPD symptoms with autism spectrum disorder and ADHD, suggesting fundamental misunderstandings about distinct neurological and psychological conditions. Self-diagnosis emerged as a dominant theme, with commenters expressing both distrust of professional mental health services and a strong desire for identity validation through psychiatric labels. Users extensively discussed relationship difficulties associated with BPD, sharing personal coping strategies and interpersonal challenges. This represents the largest systematic analysis of social media discourse around personality disorders to date. The findings highlight how platforms like TikTok function simultaneously as support networks and misinformation ecosystems for mental health content. The research underscores a critical gap in public mental health literacy, particularly around differential diagnosis between personality disorders and neurodevelopmental conditions. For health-conscious adults, this analysis reveals how algorithmic content delivery may amplify psychiatric misconceptions, potentially leading to inappropriate self-treatment or delayed professional intervention. The study's methodology—systematic collection and thematic analysis of user-generated content—establishes a new framework for understanding public health perceptions in digital spaces.