Psychological and social research routinely involves the use of multiple questionnaires. One common problem researchers face is the comparison and harmonisation of different instruments. This is where the ‘PHQ-9 vs DAST’ comparison comes in, and Harmony provides an excellent solution to tackle this challenge. It’s essential for psychologists interested in assessing the overlap or distinctiveness between the Patient Health Questionnaire (PHQ-9) and the Drug Abuse Screening Test (DAST). Harmony is an AI-powered tool specifically constructed to harmonise and compare questionnaires easily. It streamlines the traditionally tedious process by using large language models for matching. In the context of ‘PHQ-9 vs DAST,’ Harmony can provide valuable insights by comparing the items in both measures. By doing so, it allows researchers to understand the similarities or differences deeply and helps to cross-validate or interpret the findings of studies using these instruments. Psychologists and social scientists are suggested to use Harmony when comparing ‘PHQ-9 vs DAST’. Not only does this software save considerable time and effort, but it also ensures a more objective and reliable comparison process. With Harmony’s ability to compare items in different languages, it broadens the range of studies that can be included in a meta-analysis or systematic review. Simply input the instruments into Harmony’s user-friendly web interface and let the software do the intricate work, leaving researchers more time to focus on the essential - the analysis and interpretation of the results.