Early cognitive improvements realized in bipolar disorder
medwireNews: Patients with bipolar disorder can expect to experience improvements in select cognitive domains in the first year after an initial manic episode, longitudinal study findings suggest.
The results showed that while patients had consistently poorer cognitive performance than mentally healthy individuals in most cognitive domains on the Cambridge Neuropsychological Test Automated Battery, there was evidence of a significant linear improvement over time in processing speed and executive function.
“[T]he finding of potential cognitive improvement shortly after diagnosis is encouraging,” says the research team, led by Ivan Torres (University of British Columbia, Vancouver, Canada).
A total of 65 patients treated for an initial manic episode participated in the study, and were comparable to 36 mentally healthy participants with regard to age and premorbid IQ. Of these, 42 and 23, respectively, completed the 1-year study.
The patients had significantly poorer processing speed and executive function at baseline than mentally healthy individuals, with mean z-scores of –0.51 versus –0.08 and –0.11 versus 0.45 out of a range of –4 to 4, respectively.
But the two groups did not differ significantly in these cognitive domains by the end of the first year, with corresponding mean scores of –0.03 versus 0.03 and 0.32 versus 0.47.
“Given the frequently reported association between executive functioning or processing speed and functional outcome, it can be surmised that the cognitive gains that patients exhibited in the present study have the potential to result in meaningful improvement in daily patient functioning,” the researchers note in Bipolar Disorders.
By contrast, performances in other domains, such as verbal learning and memory and nonverbal memory and working memory, continued to be impaired in the patients throughout the first year after diagnosis.
The improvements in executive functioning and processing speed over time were not associated with symptom improvement; rather, improvements in executive functioning were greater among patients who stopped taking antipsychotic agents during the study and poorer among those who a history of alcohol or substance abuse.
“[T]he data emerging from the present study suggest that the early cognitive course of cognitive functioning in bipolar disorder is likely complex and impacted by multiple factors, with cognitive deficits and improvements likely arising from multiple sources,” say the researchers. They call for more research to help tease out these multiple contributing factors.
medwireNews (www.medwirenews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2013
By Lucy Piper, Senior medwireNews Reporter