Dear DOCTOR Owen:

My wife has been taking lithium for bipolar depression (also called manic depression). Her doctor says that she really needs this medication. She has gained 60 pounds since starting on the lithium. He told us that the weight gain is a side effect. Is there anything that can be used in its place or that will reverse these effects?

Befuddled by Bipolar

Dear “Befuddled”:

Weight gain as a side effect of lithium treatment has been reported since 1970. Fourteen studies have been conducted on this matter, revealing that:

• 11%–65% of patients experienced weight gain.
• 21% of patients had a weight gain of more than 22 pounds.
• 2% gained more than 44 pounds.

Weight increased most within the first and second years of lithium treatment, and then leveled off. There was an increased risk of weight gain among patients who were quite heavy at the onset of treatment—especially females—and who had high lithium serum levels.

Several reasons may explain the weight gain associated with lithium, which:

1. Often increases thirst and fluid intake, which may result in the intake of high-calorie fluids such as soft drinks or juices.
2. May increase carbohydrate and lipid storage—people deposit fat more easily.
3. Inhibits adenylate cyclase, which increases the incorporation of sugar into fat cells, resulting in increased fat storage.
4. May induce an under-active thyroid in approximately 5% of patients. The thyroid drives metabolism. Under-active thyroid production slows the metabolism.

Here are some suggested treatments to overcome the weight gain. However, none of them are based on good studies: (1) medication to activate patients’ thyroid glands; (2) diet medication (theoretically, can cause a relapse of the mania component of the illness); and (3) Wellbutrin SR®, or Buproprion, may partially antagonize the negative effects of the lithium. Some psychiatrists prescribe Wellbutrin SR® to treat the depressive component of bipolar disorder.

Most patients who are ill enough to be placed on lithium need the drug. Therefore, it is advisable for her to take the medication as prescribed and then deal with the weight-gain risk. Behavioral Diet Therapy programs that use structured diets to enforce fewer calories are useful. However, participants in these programs must be cooperative—which may be difficult for some bipolar patients.

I believe that a prophylactic diet program should be offered to those patients who might elect not to take the medication because of the weight gain or to those who will likely develop weight-related medical problems—such as diabetes, high blood pressure, or back and joint disease. Exercise is very helpful for the weight and the mechanical (knees, joints, hip, etc.) problems, and may improve the depression as well.

By all means, make sure the doctor checks your wife’s lithium levels on a regular basis to assure compliance with the medication and minimize the risk of under-active thyroid. The most common problem I see with bipolar patients is the sense of “cure” they experience after a prolonged remission. Relapse is not a pretty sight and can be life-threatening. Talk to your wife about her weight-gain concerns, and offer her your love and support. Do not look upon weight gain as a trivial problem. It is not!