Personality profile can predict course of illness in bipolar disorder
MedWire News: Patients with bipolar disorder show a distinct personality profile marked by high neuroticism and openness among other traits, which cannot be accounted for by state-based mood episodes alone, study results show.
Furthermore, differences in personality profiles among patients in remission can predict future illness course in terms of proneness to manic or depressive episodes.
"Trait theories of personality propose lifelong, stable dimensions distributed as a continuum in the population," Jordan Smoller (Massachusetts General Hospital, Boston, USA) and colleagues comment in the journal Psychological Medicine.
Current research suggests the existence of five major traits in the population at large: Openness to experience, Conscientiousness, Extraversion, Agreeableness, and Neuroticism - sometimes referred to as OCEAN.
For some of these traits, extreme scores confer an increased likelihood of a psychiatric diagnosis - neuroticism being closely associated with major depression for example.
The relationship between personality and symptoms is particularly complex in bipolar disorder because personality scores can be affected by mood state and by residual symptoms present even during euthymic states.
To separate the influences of mood-related state and underlying traits, the researchers assessed 2247 bipolar disorder patients who were participanting in the longitudinal Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) study.
Patients were assessed during manic, depressive, and euthymic phases using the NEO Five-Factor Inventory.
Overall, patients with bipolar disorder displayed a distinct personality profile characterized by high neuroticism and openness, and low agreeableness, conscientiousness, and extraversion, compared with the population average.
By comparison with a separate cohort, openness was found to distinguish bipolar disorder from major depressive disorder.
Patients in a manic phase of illness tended to show increased extraversion and decreased agreeableness, while depressed patients showed higher neuroticism and lower extraversion compared with the overall patient data.
Notably, during euthymic phases, high neuroticism and low extraversion scores predicted a future depression-prone course while increased openness predicted a manic-prone course.
The findings clearly demonstrate associations between bipolar disorder and personality traits, but they do not define their direction of causality Smoller et al note.
They comment: "This study cannot differentiate between the possibility that bipolar disorder and personality traits have shared genetic causes and the 'scarring ' hypothesis, ie, that prior illness episodes change personality.
"Testing this would require repeated assessment of personality and psychopathology in longitudinal designs, establishing baseline personality before onset of illness and following personality change in individuals who do and do not develop bipolar spectrum disorders."
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By Andrew Czyzewski