Data Analysis
Results from all studies were analysed concurrently, following the convergent integrated approach in Hong’s typology 40. We treated the data in the “qualitized” declarative statements as qualitative data and used a staged constant comparative coding strategy adapted from Grounded Theory 49, which we have previously used in integrative qualitative meta-synthesis45, 50, 51. This is an inductive approach to analysis which starts with initial rounds of coding to describe and condense the findings of individual studies. The analysts then proceed to generate categories from these descriptive codes and later move to a constant comparative analysis. During comparative analysis we paid attention to factors such as the legal status of cannabis, comparator substances, funding source, time of publication, sampling strategy, discipline of authors. Analysis was led by MV, JP, AP, ST. All analytic interpretations were negotiated during regular meetings with the whole research team.