The purpose of this study is to determine if lamotrigine therapy is associated with improvement in mood, memory and hippocampal size and function in patients receiving chronic corticosteroid therapy. Standard care for mood changes associated with corticosteroid therapy, if severe, includes antidepressants or other medications which can influence mood. No therapies, other than dose reduction or discontinuation, are currently available for memory loss associated with corticosteroid treatment. However, very little information is available on the treatment of either mood or memory changes associated with corticosteroid treatment, thus the proposed project may improve standard care.