Neurocognitive impairment across the bipolar spectrum

Area of Science:

• Neuroscience
• Psychiatry

Background:

• Bipolar disorder (BD) is a significant mental illness impacting ~4.4% of the population.
• Neurocognitive impairment is a core feature of BD, persisting even during euthymia (periods without symptoms).
• Approximately 40-60% of euthymic BD patients exhibit neurocognitive disturbances, influencing functional outcomes.

Purpose of the Study:

• To review neurocognitive disturbances within the bipolar spectrum, with a focus on bipolar II disorder (BD-II).
• To clarify the relationship between clinical factors, neurocognition, and functional outcomes in BD patients.
• To consolidate existing literature on neurocognitive profiles in BD subtypes.

Main Methods:

• An extensive literature review was conducted, focusing on studies published from 1980 to July 2009.
• The review specifically targeted research on neurocognitive disturbances in bipolar II disorder.
• Studies included heterogeneous samples (BD-I and BD-II) and those focusing solely on BD-I.

Main Results:

• Neurocognitive deficits are prevalent across the entire bipolar spectrum, including both BD-I and BD-II.
• Deficits appear to be slightly more pronounced in bipolar I disorder (BD-I) compared to BD-II.
• The degree of similarity in neurocognitive profiles between BD subtypes remains unclear.

Conclusions:

• Neurocognitive impairments are a consistent finding in bipolar disorder, irrespective of subtype.
• Further research is necessary to delineate specific neurocognitive profiles for BD-I and BD-II.
• Establishing a consensus on neuropsychological assessment methods is crucial for comparative studies in BD.