Hi widgets; It really depends on the person and the med. The side effects that are listed are anything that a participant in a drug trial has experienced. For some the meds increase their appetite and/or slow down their metabolism. For some the meds increased their water retention so it gives a "puffy" look in the face etc. I noticed this when I was on lithium. There are meds that don't list weight gain as a side effect. Lamictal (mood stabilizer) doesn't cause weight gain and neither does wellbutrin (anti-d).