Researchers and psychologists often need to compare questionnaires like PHQ-9 and DUDIT to better understand mental health patterns and drug use. The PHQ-9 assesses depressive symptoms, while DUDIT evaluates drug use disorders. The use of Harmony, an AI-based harmonisation tool, makes this comparative process easier and quicker. When comparing PHQ-9 vs DUDIT, Harmony’s intelligent natural language processing abilities are able to detect variances across the questionnaires. It provides a percentage match for each item between PHQ-9 and DUDIT, allowing for a nuanced understanding of how different questions contribute to mental health diagnosis. Harmony’s support of multiple languages makes it ideal for international studies, adding to its efficiency and comprehensive usage. For those researching the sphere of mental health disorders and drug use, using Harmony for PHQ-9 vs DUDIT comparison is highly recommended. It eliminates the tedious manual effort of comparing long PDFs and Excel files, making research quicker, more accurate, and more accessible. The PHQ-9 vs DUDIT comparison becomes much robust and streamlined with Harmony’s intelligent and user-friendly capabilities. It is the ultimate tool for harmonising questionnaire items across multiple languages and domains.