The neuropsychological functioning of depressed suicide attempters with bipolar disorder I and bipolar disorder II
Leo Sher, M.D.
Our research work, “Are BPI and BPII suicide attempters distinct neuropsychologically?” was published 15 years ago in the August 2006 issue of the Journal of Affective Disorders (1). The objective of the study was to compare the neuropsychological functioning of depressed suicide attempters with bipolar disorder I (BPI) or bipolar disorder II (BPII) and healthy controls.
Fifty-one individuals with bipolar disorder (BPI n=32, BPII n=19) and a history of suicide attempt were compared with 58 healthy controls with respect to neuropsychological functioning in the following domains: motor functioning, psychomotor performance, attention, memory, working memory, impulsiveness and language fluency. Patients were between 18 and 57 years old (M = 33.67, S.D. = 10.0) and 28.3% (N = 17) of subjects were male. BP patients were in a depressed episode as a means of equating the groups with respect to clinical state.
Participants with BPI and BPII performed significantly more poorly than healthy controls on tests of Digit Symbol Test of psychomotor functioning, the N Back Test of working memory and the Go-No-Go Test of impulsiveness. Participants with BPI were significantly worse than controls but not those with BPII on the Test of Verbal Fluency. Participants with BPII performed significantly worse than either controls or those with BPI on the Simple Reaction Time Motor Test and the Stroop Test of attention.
While participants with both BPI and BPII performed more poorly than healthy controls, individuals with BPII also performed more poorly than those with BPI on some tests suggesting that they may have a unique syndrome. The assumption that BPII is a milder, less disruptive form of bipolar disorder is not supported in this study. Our study suggests that patients with BPI and BPII ought to be studied separately in investigations of bipolar disorder.
- Harkavy-Friedman JM, Keilp JG, Grunebaum MF, Sher L, Printz D, Burke AK, Mann JJ, Oquendo M. Are BPI and BPII suicide attempters distinct neuropsychologically? J Affect Disord. 2006 Aug;94(1-3):255-9. doi: 10.1016/j.jad.2006.04.010. Epub 2006 Jun 5.