Symptoms of depression and survival experience among three samples of smokers trying to quit.

Symptoms of depression have been associated with increased smoking prevalence and failure to quit smoking in several cross-sectional and population-based studies. Few studies, however, have prospectively examined the ability of current symptoms of depression to predict failure to quit smoking in treatment-motivated smokers. Pretreatment depressed mood was assessed by 3 different methods in 3 separate samples, 2 of which comprised smokers receiving combined pharmacological and behavioral treatments and a 3rd in which smokers received self-help materials only. In all studies, time in days from quit day until the 1st cigarette was ascertained to document survival. Survival analyses showed that in all 3 studies survival time was significantly and negatively related to measures of even very low levels of pretreatment depressed mood. Results were replicated across 3 independent samples and were robust and uniformly clear, indicating that low levels of depressive symptoms assessed at baseline predict time to 1st cigarette smoked after attempted quitting.