attributed to methodological factors, including lack of statistical control for tobacco use, failure to include individuals who use cannabis frequently, and failure to include individuals who have used cannabis heavily for extended periods of time. In a recent study that overcame some of these limitations, adults who used both cannabis and tobacco had poorer smoking-specific health problems (e.g., emphysema; wheeze/cough) and poorer general health problems relative to adults who used cannabis only (Rooke et al., 2013). However, this study examined a small, convenience sample of individuals who used cannabis, and it is unknown how these findings generalize to more representative cannabis- and tobacco-using samples.
