Exploration-Exploitation and Suicidal Behavior in Borderline Personality Disorder and Depression

Area of Science:

• Behavioral Science
• Reinforcement Learning
• Psychiatry

Background:

• Suicidal crisis often involves difficulty finding solutions and neglecting alternatives.
• Previous research has not formally examined exploration-exploitation tradeoffs in suicidal behavior.

Purpose of the Study:

• To investigate exploration and exploitation in suicidal behavior using reinforcement learning principles.
• To understand how individuals with suicidal ideation or attempts resolve choices between familiar and novel options.

Main Methods:

• Two case-control behavioral studies and a 21-day prospective ambulatory study were conducted.
• Participants included adults with borderline personality disorder (BPD) and major depressive disorder (MDD), with varying suicide attempt histories and controls.
• Behavioral indices of exploration, exploitation, suicide attempt lethality, and suicidal ideation were assessed.

Main Results:

• Individuals with high-lethality suicide attempts explored fewer options and failed to shift from unrewarded choices.
• Those with low-lethality attempts exhibited excessive behavioral shifts.
• Underexploration prospectively predicted incident suicidal ideation.

Conclusions:

• Narrow exploration and difficulty abandoning inferior options are associated with serious suicidal behavior and chronic suicidal thoughts.
• Low-lethality suicidal behavior may involve a low threshold for disadvantageous actions.
• These findings offer insights into decision-making processes in suicidal behavior.