Relationship between delay discounting and depression in cigarette smokers and non-smokers

Abstract

BackgroundDelay discounting (DD) is a measure of impulsivity that describes the devaluation of reinforcers when delayed. Several studies have associated greater DD with drug dependence and certain mental disorders such as depression. The aim of the present study is to determine whether there are differences in DD rates between smokers and non-smokers with different levels of depressive symptoms. MethodsThe study included 200 individuals: smokers without depressive symptoms (n = 40), smokers with moderate depressive symptoms (n = 40), smokers with severe depressive symptoms (n = 40), non-smokers with moderate depressive symptoms (n = 40), and controls (n = 40). The Beck Depression Inventory-II (BDI-II) and the Structured Clinical Interview (SCID-I) of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) were used to assess depressive symptoms and the presence of major depressive disorder. All participants completed a computerized DD task with hypothetical monetary values. ResultsThere was a significant correlation between AUC and BDI-II measures in non-smokers. There were statistically significant differences in DD between the comparison groups (p < .001). Controls were less impulsive than the other groups. ConclusionsSmoking and depression are related to high DD; however, there is no additive effect on impulsivity rates when both conditions appear together.