The two cannabis measures were strongly intercorrelated (Kendall’s τ = 0.793), but they were also related to nicotine dependence (Kendall’s τ = 0.307 and 0.330 for SDS and CAST, respectively), and alcohol related problems (Kendall’s τ = 0.172 and 0.161 for SDS and CAST, respectively; all correlations are significant). The gene discussed is CAST; the disease is nicotine dependence.