BACKGROUND: Artificial intelligence (AI) tools like ChatGPT have gained attention for their potential to support patient education by providing accessible, evidence-based information. This study compares the performance of ChatGPT 3.5 and ChatGPT 4.0 in answering common patient questions about LBP, focusing on response quality, readability, and adherence to clinical guidelines, while also addressing the models' limitations in managing psychosocial concerns. METHODS: Thirty frequently asked patient questions about LBP were categorized into four groups: Diagnosis, Treatment, Psychosocial Factors, and Management Approaches. Responses generated by ChatGPT 3.5 and 4.0 were evaluated on three key metrics: 1. RESPONSE QUALITY: Rated on a scale of 1 (excellent) to 4 (unsatisfactory). 2. DISCERN CRITERIA: Evaluating reliability and adherence to clinical guidelines, with scores ranging from 1 (low reliability) to 5 (high reliability). 3. READABILITY: Assessed using seven readability formulas, including Flesch-Kincaid and Gunning Fog Index. RESULTS: ChatGPT 4.0 significantly outperformed ChatGPT 3.5 in response quality across all categories, with a mean score of 1.03 compared to 2.07 for ChatGPT 3.5 (p <
0.001). ChatGPT 4.0 also demonstrated higher DISCERN scores (4.93 vs. 4.00, p <
0.001). However, both versions struggled with psychosocial factor questions, where responses were rated lower than for Diagnosis, Treatment, and Management questions (p = 0.04). CONCLUSION: ChatGPT 3.5 and 4.0 limitations in addressing psychosocial concerns highlight the need for clinician oversight, particularly for emotionally sensitive issues. Enhancing AI's capability in managing psychosocial aspects of patient care should be a priority in future iterations.