Reward magnitude-specific delay discounting differentiates mania versus depression risk

Area of Science:

• Neuroscience
• Psychiatry
• Behavioral Economics

Background:

• Mania/hypomania, a core feature of bipolar disorder (BD), involves heightened impulsivity.
• Delay discounting, assessing preference for immediate rewards, is a key measure of impulsivity.
• It's unclear if delay discounting distinguishes BD from non-BD or predicts mood episode risk.

Purpose of the Study:

• To determine if delay discounting differentiates individuals with BD from those without.
• To investigate delay discounting as a behavioral marker for mania/hypomania versus depression risk.

Main Methods:

• Recruited 40 individuals with BD and 187 non-BD individuals.
• Stratified non-BD participants into mania/hypomania and depression risk tertiles.
• Assessed delay discounting rates (k values) using the 27-Item Monetary Choice Questionnaire.
• Analyzed data using Kruskal-Wallis and Dunn's tests.

Main Results:

• Significant group differences in delay discounting rates (k values) were found for both mania/hypomania and depression risk groups.
• Delay discounting for medium reward magnitudes significantly differentiated BD from non-BD individuals.
• Heightened mania/hypomania risk was distinguished from depression risk based on delay discounting for medium rewards.

Conclusions:

• Delay discounting, particularly for medium reward magnitudes, serves as an objective behavioral marker.
• This marker can differentiate bipolar disorder from non-bipolar individuals.
• It also distinguishes between mania/hypomania and depression risk, aiding in risk detection.