Personality traits seem to differ between patients with bipolar I and II disorder, according to a new Korean study.
The researchers found that patients with bipolar II disorder (BD II) had significantly higher levels of neuroticism and lower levels of extraversion than those with bipolar I disorder (BD I).
“Further studies, including longitudinal assessments, are needed to determine how these personality traits are differentially linked with the etiology and clinical expressions of BD I and BD II,” said Dr. Yeon Ho Joo of the University of Ulsan College of Medicine, Seoul and team in Psychiatry Investigation.
People with bipolar disorder type I have had at least one manic episode and periods of major depression.
Those with bipolar II disorder have never had full mania but instead experience periods of high energy levels and impulsiveness (hypomania) that are not as extreme as mania.
The study included 85 BD I (47 females) and 43 BD II (23 females) patients, between the ages of 18 and 65 years, who had been in a stable state of mind for at least 8 weeks. The two groups were similar in regards to gender distribution, age, education level, and socioeconomic status.
Researchers assessed the patients with the NEO Personality Inventory (NEO-PI-R) — a 240-item measure of five personality dimensions (neuroticism, extraversion, openness, agreeableness, and conscientiousness). Each of the dimensions has six sub-sections.
The team found that BD II patients had significantly higher scores than BD I patients on the neuroticism dimension and four of its sub-sections, particularly anxiety, depression, self-consciousness, and vulnerability.
On the other hand, patients with BD II had significantly lower scores than BD I patients on the extraversion dimension and its positive emotion sub-section.
Furthermore, although there were no notable differences between the groups in scores on conscientiousness, BD II patients had significantly lower scores than BD I patients for the sub-sections of competence and achievement striving.
There were no significant differences between the groups regarding openness and agreeableness dimension scores.
“Our results clearly suggest that BD I and BD II patients have distinct personality which supports the separation in enduring trait dimensions between the two subtypes,” said Joo and team. “The most evident differences were on measures of neuroticism and extraversion.”
Source: Psychiatry Investigation