"very drowsy for the first week of taking it, but once your body gets used to it, it is a great mood stabilizer. i&#039;ve been on it 6 years and it calms the edginess and irritability with bipolar. also makes you sleep like a rock. my weight only changed when lithium was added to my meds. no significant weight gain for me. if i go a few days without it, i notice i&#039;m on edge constantly."