I also have treatment resistant depression and am constantly changing medication combinations. Basically every 6 months I have to have a new combo and this has been going on for 15 years. I have a lot of memory loss issues and find it extremely difficult to recall information especially when my depression is severe. When I'm at my worst, my therapist and family can tell because I can't think very fast and respond slower and I can't concentrate or do anything that requires complicated thinking. So you are not alone, hang in there...