Citation: Pacek LR, Copeland J, Dierker L, Cunningham CO, Martins SS, Goodwin RD. Among whom is cigarette smoking declining in the United States? The impact of cannabis use status, 2002-2015. Drug Alcohol Depend. 2018 Oct 1;191:355-360. doi: 10.1016/j.drugalcdep.2018.01.040. Epub 2018 Apr 11.