IV Analysis
depression, anxiety
IV analysis suggested that depression increased relative to continuing smoking (β = 1.48; 95% CI, −0.67 to 3.63), as did anxiety (β = 1.60; 95% CI, −1.01 to 4.22), but both estimates were imprecise. Post hoc power analysis suggested that we had very little power to exclude effect sizes like those seen in our observational analyses (eAppendix 4 in 