Generally most during hypomanic or full blown manic episodes, though even during them I have also been known to gain some weight. Weight gain is more common during my depressive episodes, though I have even had weight loss during a couple of those. It has really depended on the characteristics of the episode and where I am or what is happening.

In my senior year at college, I lost a chunk of weight due to hypomania/mania and a respiratory infection. I went from maybe 134 to 118 lbs, the latter being EXTREMELY skinny, for me. I moved to California with my then boyfriend, and over a two year period not only regained the weight, but during a bit of mixed depression, went as high as 152 or 154 lbs. When we broke up, I moved to Taiwan. I became hypomanic then pure depressed. During both I barely ate and was walking about 10 miles or more, each day. Between that, and a then manic adventure in Hong Kong and Thailand, I got back down to maybe 134 lbs. All of this was before my diagnosis of bipolar disorder. I had only been on medications, briefly (days or a couple weeks), a couple times, and they had been only antidepressants (Prozac, later an unidentified antidepressant prescribed in Taiwan), which pushed me into the manias.

Since my bipolar diagnosis, like many, I was on some pretty weight unfriendly medications. I did have some very severe manias since then. Most of which I was hospitalized for. Despite them, I still gained weight. I remember extreme hunger due to the medications and mental extremes. When I finally crashed, between the medications and a severe depression, for which I had ECT, I went up to 192 lbs while on a combo of Depakote ER and Invega. Then my depression was mostly relieved, and I found myself in a long-term low grade hypomania (with blips of full blown mania). I lost about 40 lbs in six months, most of which I kept off for a good six years when STILL in a low grade hypomanic state. That 40 lbs weight loss was while I took 900 mg Lithium ER, 1,400 mg Tegretol XR, 100 mg Lamictal, 160 mg Geodon, and 10 mg Navane (Thiothixene), simultaneously. My weight only started to slowly inch up when Seroquel XR took over for the Navane, though I have been mostly stable since then. I have not reached my all time high again. I'm now 50 years old, so I assume some of the weight is age, lifestyle, and genetics related.