Differential deficit in executive control in euthymic bipolar disorder.
Patients with remitted bipolar disorder (BD) have persistent cognitive deficits, but the nature and specificity of this deficit remain unclear. The authors evaluated the executive hypothesis of BD by determining whether (a) patients' executive deficits qualify as differential deficits, that is, that these significantly exceed deficits in other cognitive domains; (b) deficits in particular executive functions are evident, and (c) executive difficulties mediate declarative memory deficits in BD. The cognitive performance of 63 prospectively verified euthymic bipolar patients was compared with controls, using J. Baron and R. Trieman's (1980) method of testing for differences in nonindependent correlations. There were no differential deficits within the executive domain. Patients' generic executive performance was differentially impaired relative to primary verbal memory and retention in declarative memory, but not relative to their declarative recall, recognition, or their psychomotor performance. However, patients' executive deficit was not an artifact of their poor psychomotor performance. Executive performance accounted for all but a trivial portion of the between-group variance in declarative memory. Persistent cognitive difficulties in euthymic bipolar disorder (EBD) are thus usefully characterized as a generic dysexecutive syndrome.
Thompson
Jill Maria
JM
Department of Psychiatry, University of Newcastle Upon Tyne, Newcastle Upon Tyne, UK. jillmaria.thompson@astrazeneca.com
Gray
John M
JM
Crawford
John R
JR
Hughes
John H
JH
Young
Allan H
AH
Ferrier
I Nicol
IN
D001714:Bipolar Disorder / Q000453:epidemiology*; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000453:epidemiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D011446:Prospective Studies; D011596:Psychomotor Disorders / Q000175:diagnosis / Q000453:epidemiology; D020127:Recovery of Function; D012153:Retention, Psychology; D012720:Severity of Illness Index