People with bipolar disorder (BD) tend to score differently on the Big Five personality traits compared to the general population, though these are averages and not universal. Research highlights:

1. High Neuroticism: The strongest and most consistent finding. Individuals with BD often score 1–1.5 standard deviations above the norm, reflecting greater emotional instability, mood reactivity, and vulnerability to stress. This persists even in euthymic (stable) phases.
2. High Extraversion (BD I) / Moderate (BD II): Those with bipolar I (full mania) typically show elevated extraversion sociable, energetic, sensation-seeking especially during hypomanic/manic episodes. Bipolar II may show more moderate levels.
3. High Openness to Experience: Creative, imaginative, and unconventional thinking is common, linked to hypomanic cognition. BD samples score ~0.5 SD higher than controls.
4. Low-to-Average Conscientiousness: Lower impulse control, disorganized goal-directed behavior (especially in mania), and reduced follow-through lead to below-average scores, though this improves in stable periods.
5. Variable Agreeableness: No strong overall difference, but irritability in mania or withdrawal in depression can temporarily lower scores.

These traits predate illness onset in many cases and may increase BD risk (especially high neuroticism + high extraversion). However, traits fluctuate with mood: extraversion and openness rise in hypomania, conscientiousness drops. Medication, therapy, and remission can normalize profiles.

Key caveat: The Big Five does not diagnose BD. Many neurotypical people share these traits, and BD individuals vary widely. Personality assessment should complement not replace clinical mood tracking.