I wish I could say I didn't gain weight when I went on Seroquel but I gained alot. The interesting thing was that as my dosage was decreased (I started at 200mg and went down to 25mg) I decreased in size as well! I couldn't believe it. I never expected that but it was the Seroquel; nothing else had changed. I didn't even realize I was losing until one day I noticed that my clothes were huge. Weird, huh?