To our knowledge this is the first genomewide survival analysis of age at onset of cannabis use to date. The survival modeling approach appears to be appropriate and computationally tractable given the detailed genotypic data currently available (an example dataset and annotated scripts to run such an analysis can be found at http://cameliaminica.nl/research.php). Clearly, further research on the genetic basis of age at onset would be of interest as the trait may serve as a proxy for both heavy use and experimentation with other drugs.
