PURPOSE: Previous analysis of data from CATIE showed that patients randomly assigned to switch to a new medication were more likely to discontinue study drug than those who stayed on the medication they had been taking prior to randomization. This study addresses additional outcomes measures evaluating symptoms, neurocognition, quality of life, neurological side effects, weight, and health costs. First, considering patients randomized to olanzapine or risperidone, outcomes among patients who had been on the drug to which they were randomized prior to CATIE (N=129 "stayers") were compared to outcomes of those who switched to either of these two drugs (N=269 "switchers"). A second set of analyses considered patients on baseline monotherapy with olanzapine (N=297); risperidone (N=252) or quetiapine (n=87) and compared those randomly assigned to stay on each of these medications with those assigned to switch to any of the other five phase 1 medications in CATIE. In mixed models of each outcome the independent variable of primary interest represented stay vs. switch, with multivariate adjustment for potential confounding factors.
RESULTS: With one exception, there were no significant differences between stayers and switchers on any outcome measure in either set of analyses. The exception was that, in the second set of analyses, patients who stayed on olanzapine showed greater weight gain than those who switched from olanzapine to other drugs.
CONCLUSION: Switching to a new medication yielded no advantage over staying on the previous medication. Staying on olanzapine was associated with greater weight gain.