Valproic Acid is an anticonvulsant mood-stabilizer licenced for the acute treatment (but not maintenance treatment) of mania in Bipolar I Disorder. Research has shown that lithium usually is superior to valproic acid for maintenance treatment of Bipolar I Disorder. Valproic acid sometimes increases weight and hair loss, but there is no evidence that it increases the risk of diabetes mellitus.
I have been on Depakote ER (2x250mg) per day for about 1.5 years, and I am ready to ask my new pdoc to prescribe lithium. The Depakote has not been effective lately on stablizing my mood. In fact, I am just emerging from a 2-week long negative manic phase unlike any I've ever had. I had high energy, but it was hectic and nerve wracking. I was paranoid, extremely short tempered, angry, etc; I'd rather be depressed than manic.
A niece of mine was on Depakote for years (she was alcoholic), but she said it just made her gain weight. She still had violent mood swings before she died. I, too, feel like the weight gain and breast enlargement are unbearable, so I'm switching meds as soon as I can.
I guess it doesn't work the same for everyone, because I'm currently taking it and it's been much more effective than Lithium which I tried more than a year ago.