HVLT-R test total words recalled scores will be compared between baseline and exit of the active medication phase and placebo phase using a within subjects design and paired t-tests. Based on our prior experience working with corticosteroid-dependent patients we have found them to be very compliant with clinical treatment. Thus, we do not anticipate large numbers of dropouts or missing data. In the case of missing data we will use the last observation carried forward. In our lamotrigine study in a similar population, we found a change in total words recalled on a word list and on the Stroop. Assuming a similar change with memantine, using double-sided, paired t-tests, we could detect a difference with a change in the placebo group with participants on the HVLT-R and up to with participants on the Stroop. Thus, although this is primarily a pilot study to obtain effect sizes for future, larger trials funded by NIH, it should have power to detect clinically meaningful differences between medication and placebo.