More threads by David Baxter PhD

David Baxter PhD

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Qualitatively similar cognitive deficits in bipolar disorder and schizophrenia
06 July 2007
Biol Psychiatry 2007; 62: 179-186

Bipolar disorder patients suffer cognitive deficits that are milder than those of schizophrenia patients but qualitatively similar, say US researchers.

David Schretlen (Johns Hopkins University School of Medicine, Baltimore, Maryland) and colleagues compared the nature and severity of cognitive deficits in 106 schizophrenia patients, 66 bipolar patients, and 316 mentally healthy controls.

They administered 19 cognitive tests to measure six cognitive domains ? psychomotor speed, attention, executive function, fluency, verbal memory, and visual memory.

Both patient groups performed significantly worse on the tests than controls, after adjusting for age, gender, ethnicity, education, and estimated premorbid IQ.

Schizophrenia patients performed significantly worse than controls on all cognitive tests and for each domain, and bipolar patients performed significantly worse than controls for every cognitive domain and all but one cognitive test.

The cognitive deficit mean effect sizes for schizophrenia and bipolar patients were 0.97 and 0.59, respectively.

Schizophrenia patients performed significantly worse than bipolar patients on 11 of the 19 tests, and five of the six cognitive domains. Bipolar patients performance was as poor as that of schizophrenia patients on tests of attention, word and design fluency, and recognition discrimination.

Schretlen et al conclude in the journal Biological Psychiatry: "The cognitive deficit effect sizes shown by schizophrenia and bipolar disorder patient groups correlated quite highly, indicating that the two groups exhibited qualitatively similar patterns of cognitive impairment despite differences in the overall severity of their deficits."

These results suggest that these disorders represent a "continuum of psychosis," or share some genetic or biological overlap, the team adds.



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cool article - I haven't been diagnosed with bipolar yet but I have a feeling I may be in the near future, when my new psychiatrist comes back from holidays.
This is interesting! I thought serotonin played an important role as in can too much serotonin create mania?

And what is hypomania?
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