Cognition in bipolar versus depression

Why assess differences in cognition between bipolar disorder and major depression?

Bipolar disorder is characterised by intermittent periods of mania and depression, while people with major depression do not experience mania. Mania involves elevated or irritable mood, which is often accompanied by inflated self-esteem or grandiosity, decreased need for sleep, distractibility, psychomotor agitation or excessive involvement in pleasurable activities. Manic episodes may involve psychotic symptoms including grandiose delusions. Depression is characterised by extended periods of sadness, a loss of interest in activities, loss of appetite, decreased energy, feelings of worthlessness, and difficulty concentrating. Suicidal thoughts may also be present.

Neurocognitive deficits are a feature of bipolar disorder and may also be present in people with major depression. Domains of intelligence, memory, executive functioning, language, information processing and attention can all be affected. Identifying any differences in these cognitive domains may assist correct diagnosis and treatment of the two disorders.

What is the evidence for cognition in bipolar disorder compared to major depression?

Moderate quality evidence suggests a medium-sized effect of better verbal memory (list learning) in people with major depression than in people with bipolar disorder, but only during euthymic phases, as there were no differences during depression phases. There were no significant differences between people with major depression or bipolar disorder on tasks assessing attention, processing speed, and executive functioning.

March 2019

Last updated at: 10:05 pm, 30th March 2019
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