Objectives
Neurocognitive deficits have been widely reported in euthymic Bipolar Disorder (BD) patients and contribute to functional disability. However, the longitudinal trajectory of these deficits remains a subject of debate. Although most research to this date shows that neurocognitive deficits tend to be stable among middle‐age BD patients, it remains plausible that deterioration occurs at either early or late stages of this condition.
Methods
We conducted a comprehensive meta‐analysis of studies that reported longitudinal neurocognitive performance among individuals with BD either within the year of their diagnosis or among late‐life BD patients. Pooled effects of standardized mean differences (SMDs) for changes in neuropsychological scores over follow‐up were estimated using random effects model. We also examined effect moderators, such as length of follow‐up, mood state, or pharmacological load.
Results
Eight studies met inclusion criteria for recent‐onset and four studies for late‐life BD analysis. No evidence for a deterioration in neurocognitive functioning was observed among recent‐onset BD patients (8 studies, 284 patients, SMD: 0.12, 95% CI −0.06 to 0.30, mean follow‐up: 17 months) nor for late‐life BD patients (4 studies, 153 patients, SMD: −0.35, 95% CI −0.84 to 0.15, mean follow‐up: 33 months). None of the moderators were shown to be significant.
Conclusions
These results, when appraised together with the findings in middle‐life BD patients and individuals at genetic risk for BD, suggest that neurodevelopmental factors might play a significant role in cognitive deficits in BD and do not support the notion of progressive cognitive decline in most patients with BD.