Reduced hedonic capacity in euthymic bipolar subjects: a trait-like feature?

Area of Science:

• Neuroscience
• Psychiatry
• Clinical Psychology

Background:

• Assessing hedonic capacity in euthymic bipolar disorder patients.
• Comparing hedonic capacity in bipolar disorder, major depressive disorder, and healthy controls.
• Investigating potential differences in hedonic capacity between patient groups and controls.

Purpose of the Study:

• To evaluate hedonic capacity in euthymic bipolar disorder patients.
• To identify differences in hedonic capacity compared to remitted unipolar depressed patients and healthy controls.
• To explore if reduced hedonic capacity is a persistent trait in affective disorders.

Main Methods:

• Enrolled 107 bipolar disorder patients, 86 major depressive disorder patients, and 106 healthy controls.
• Administered the Snaith-Hamilton Pleasure Scale (SHAPS), Scale for the Assessment of Negative Symptoms (SANS), and visual analogue scale (VAS).
• Assessed hedonic capacity using SHAPS, SANS 'anhedonia/asociality' subscale, and VAS.

Main Results:

• Affective disorder patients had significantly higher scores on SHAPS, SANS 'anhedonia/asociality', and VAS compared to healthy controls.
• No significant differences in hedonic capacity scores were found between bipolar and major depressive disorder patient groups.
• A significant reduction in hedonic capacity was observed in 20.5% of bipolar patients and 24.5% of major depressed patients, versus 7.5% of controls.

Conclusions:

• Euthymic bipolar patients and remitted major depressed patients exhibit residual anhedonic symptoms.
• Altered hedonic capacity may be an enduring trait in patients with affective disorders.
• Neurobiological mechanisms underlying hedonic response and reward processing may persist irrespective of mood state.