The relationship between delay discounting and alcohol dependence in individuals with and without comorbid psychopathology.

Abstract

Alcohol use disorder (AUD) has been associated with greater discounting of delayed monetary rewards, but it is unclear whether this association is primarily related to alcohol consumption or is secondary to the presence of psychiatric comorbidities. It is also unclear if steeper rates of discounting are associated with greater AUD severity. We sought to determine whether the presence of comorbid psychiatric disorders affected the relationship between AUD and delay discounting. We also examined whether more severe AUD was associated with greater delay discounting. In this cross-sectional study, 793 adults completed a delay discounting task. Subjects were divided into four groups based on diagnosis: current AUD with psychiatric comorbidities (N = 226), current AUD without psychiatric comorbidities (N = 203), past AUD (N = 69), and healthy controls (N = 295). In those with AUD, we investigated the relationship between delay discounting and alcohol dependence symptom count and recent drinking history. We also compared individuals seeking treatment to non-treatment seeking individuals. Psychiatric comorbidities examined included mood disorders, anxiety disorders, and substance use disorders. After adjusting for age, sex, income, and education, individuals with current AUD showed significantly higher rates of delay discounting than healthy controls and individuals with a past diagnosis of AUD. The presence of comorbid psychiatric diagnoses was not associated with steeper discounting. Among those with AUD, there was no evidence for a continuous relationship between delay discounting and AUD severity or alcohol consumption. Finally, non-treatment seekers with AUD had steeper delay discounting than treatment seekers. Individuals with AUD show steeper delay discounting than healthy adults, but the effect is small and there is no added effect from comorbid psychopathology or increased AUD severity. This suggests that steeper delay discounting may have a more limited effect on human alcohol use than previously supposed.