Reward-Related Striatal Responses Following Stress in Healthy Individuals and Patients With Bipolar Disorder

Area of Science:

• Neuroscience
• Psychiatry
• Psychology

Background:

• Stress significantly impacts mood episodes in bipolar disorder (BD), yet underlying mechanisms are unclear.
• Previous research indicates stress affects reward processing differently over time in healthy individuals.
• Impaired reward processing is a hallmark of BD, and its alteration post-stress may influence disorder progression.

Purpose of the Study:

• To investigate brain responses to reward processing during the recovery phase after acute stress in patients with BD and healthy controls.
• To explore the relationship between stress, reward processing, and neural flexibility in BD.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to measure brain activity.
• Participants included 40 healthy controls and 40 patients with euthymic BD.
• Subjects underwent either an acute stress test (Trier Social Stress Test) or a no-stress condition.

Main Results:

• Acute stress elevated cortisol levels in both groups.
• Healthy controls showed increased ventral striatal responses to reward during stress recovery, but patients with BD did not.
• No group differences in reward anticipation were observed after stress.

Conclusions:

• This study reveals altered reward processing in BD patients during stress recovery.
• Findings suggest diminished neural flexibility in hedonic signaling following environmental challenges in BD.
• This neural inflexibility may heighten susceptibility to stress and contribute to long-term psychopathology.