“Broken Bones Heal Stronger” : Exploring Differences in the Discourse in CPTSD and CPTSD Recovery Communities on Reddit using Large Language Models (LLMs)

The present study investigated discourse in online mental health communities (OMHCs) for Complex Post-Traumatic Stress Disorder (CPTSD), comparing the validation-oriented subreddits r/CPTSD and recovery-oriented r/CPTSDNextSteps. Using the large language model (LLM) GPT-4o as a deductive text mining tool, it evaluated the alignment of popular posts with the Connectedness, Hope, Identity, Meaning, Empowerment (CHIME) model of personal recovery and assessed emotional tone. A total of 991 posts from r/CPTSD and 1001 posts from r/CPTSDNextSteps were scraped on April 4, 2025. Zero-shot GPT-4o scores (1-7 Likert scale) were validated against independent human raters with intraclass correlation coefficients (ICC(2,1)). Comparative analyses tested differences in GPT-4o sentiment and CHIME scores across subreddits. r/CPTSDNextSteps posts scored significantly higher in sentiment (p < .001, d = 1.06), Hope (p < .001, d = 1.68) and Empowerment (p < .001, d = 1.38), while r/CPTSD posts scored higher on Meaning (p < .001, d = -0.46). GPT-4o showed good to excellent agreement with human ratings (ICCs ≥ 0.60) for sentiment, Connectedness, Hope and Empowerment across both subreddits, but only poor to fair agreement for Identity and Meaning in r/CPTSD. The recovery-oriented r/CPTSDNextSteps indeed reflects more positive, hope-driven, and empowering discourse, while r/CPTSD emphasizes meaning. GPT-4o appears effective for analysing psychological constructs in OMHC texts, with limitations for more complex constructs. Findings highlight the distinct roles of OMHCs in CPTSD recovery and the potential of LLMs for analysing large-scale OMHC data.