KMB... From the age of 19, I was on Celexa. Stayed on it until I was 23. Tried other meds, as I found it stopped working for my depression, although it worked for my anxiety. Went back on it at 25... While on Tegretol, it caused my first manic episode/psychotic break. Went off the Celexa and Tegretol at the hospital. Started Lithium. A month later, tried Celexa again and despite being at a "therapuetic level" of Lithium, it again swung me up to mania. So I think it can happen even if on a mood stabilizer. The idea of it happening because its been in your body too long is intriguing though.