ABSTRACT
OBJECTIVE: An association between bipolar disorder and cognitive impairment has repeatedly been described, even for euthymic patients. Findings are inconsistent both across primary studies and previous meta-analyses. This study reanalysed 31 primary data sets as a single large sample (N = 2876) to provide a more definitive view. METHOD: Individual patient and control data were obtained from original authors for 11 measures from four common neuropsychological tests: California or Rey Verbal Learning Task (VLT), Trail Making Test (TMT), Digit Span and/or Wisconsin Card Sorting Task. RESULTS: Impairments were found for all 11 test-measures in the bipolar group after controlling for age, IQ and gender (Ps ≤ 0.001, E.S. = 0.26-0.63). Residual mood symptoms confound this result but cannot account for the effect sizes found. Impairments also seem unrelated to drug treatment. Some test-measures were weakly correlated with illness severity measures suggesting that some impairments may track illness progression. CONCLUSION: This reanalysis supports VLT, Digit Span and TMT as robust measures of cognitive impairments in bipolar disorder patients. The heterogeneity of some test results explains previous differences in meta-analyses. Better controlling for confounds suggests deficits may be smaller than previously reported but should be tracked longitudinally across illness progression and treatment.
Subject(s)
Affective Symptoms , Bipolar Disorder , Cognition Disorders , Mental Competency , Neuropsychological Tests , Psychotropic Drugs/adverse effects , Adult , Affect , Affective Symptoms/psychology , Age of Onset , Bipolar Disorder/complications , Bipolar Disorder/diagnosis , Bipolar Disorder/drug therapy , Bipolar Disorder/epidemiology , Cognition Disorders/diagnosis , Cognition Disorders/drug therapy , Cognition Disorders/epidemiology , Cognition Disorders/etiology , Confounding Factors, Epidemiologic , Female , Humans , Male , Mental Processes/drug effects , Middle Aged , Psychiatric Status Rating Scales , Psychotropic Drugs/administration & dosage , Risk FactorsABSTRACT
OBJECTIVE: The relationship between insight and neurocognition in bipolar disorder has not been clearly established. METHOD: A neuropsychological battery assessing attention, mental control, perceptual-motor skills, executive functions, verbal fluency and abstraction, and visuo-spatial attention was administered to 50 bipolar remitted patients and 50 healthy controls. Insight was assessed with the Scale to Assess Unawareness of Mental Disorder. RESULTS: Patients presented significantly worse neurocognitive performance. Insight was impaired in 60% of patients, and age, educational level, manic symptoms, age of disease onset, number of admissions, and performance on several neurocognitive tests correlated significantly with insight. A regression model revealed that age and Trail Making Test part B (TMT-B) performance accounted for 32% of the variance in overall illness awareness, while performance on the TMT-B alone accounted for 28% of the variance. CONCLUSION: Impaired insight and neurocognitive dysfunction seem to be present in euthymic bipolar patients. Insight in bipolar disorder may be partially dependent on intact neurocognition.
