Patients with bipolar disorder I have increased verbal learning impairment compared with those who have bipolar II, according to Corin Bourne, D.Phil., and associates.
The investigators looked at the performance of 183 bipolar I (BDI) patients with 96 bipolar II (BDII) outpatients on a modified version of the Rey Verbal Learning Task. They found that VLT scores were significantly lower in bipolar I patients, with effect sizes ranging from 0.13 to 0.17. Drug treatment and other illnesses were unrelated to the impairment, but age of onset affected outcomes in three of the five measured categories, and mood elevation incidence affected one measured category.
“Initially, both bipolar subtypes may have similar levels of verbal learning and memory performance” but BDI patients suffered steeper declines, noted Dr. Bourne of the department of psychiatry at the University of Oxford (England) and Warneford Hospital in Oxford.
Find the full study in the Journal of Affective Disorders (doi: 10.1016/j.jad.2015.04.021).
