Olanzapine is at least as effective as lithium at prolonging remission in bipolar disorder and more effective than lithium in preventing relapse into mania

To date, the results of one head-to-head maintenance trial of olanzapine versus lithium have been reported (as a poster presented at scientific meetings including the International Congress of Biological Psychiatry, Sydney, Australia, 2004). During this one-year study conducted in recently manic patients, olanzapine generally had a similar efficacy to that of lithium, although it had greater efficacy in preventing relapse into a manic episode.

GSK counterclaim: