7-UP was originally marketed as a “slenderizing” “lithiated” soda. Lithium was valued for its general health benefits back then, but was removed in the 1940’s.
The gold-standard mood stabilizer causes far less weight gain than most alternatives
STUDY: Gomes-da-Costa S et al, Neuroscience and Biobehavioral Reviews 2022;134:104266
STUDY TYPE: Systematic review and meta-analysis
FUNDING: Independent
Background
Lithium is the gold standard for bipolar because of its long-term benefits, preventing relapse, suicide, and improving functioning. Recently, two studies arrived at a surprising conclusion — that lithium causes less weight gain of all mood stabilizers except lamotrigine. One was a meta-analysis of acute studies. The other looked at reports of severe weight gain on mood stabilizers. This new analysis extends that conclusion further, including long-term trials.
The Study
Researchers reviewed 20 studies totaling over 10,000 patients with bipolar disorder, including 9 RCTs in the formal meta-analysis. They compared weight change with lithium versus placebo and versus active comparators — including quetiapine, olanzapine, valproate, and aripiprazole — across treatment durations of 8 to 52 weeks.
Lithium produced a mean weight gain of just 0.46 kg, which didn’t reach statistical significance and wasn’t different from placebo. Compared to active comparators — mainly atypical antipsychotics and valproate — lithium caused significantly less weight gain (about 1.4 kg less). Short-term studies showed more weight gain than longer ones, possibly due to early fluid retention that stabilizes over time.
Practice Implications
- Lithium may not cause detectable weight gain in these studies, but individual cases vary, and some report weight from water retention on it.
- Unlike other meds, lithium never had industry funding or a powerful PR arm to counter rumors of side effects.
- Lithium makes people thirsty, so advice patients to avoid caloric beverages (and diet sodas, which indirectly cause weight gain). Keeping thyroid in check will also prevent weight gain on it.
- Among mood stabilizers, lithium ranks right below lamotrigine in risk of weight gain, sedation (occurs in 1:28 people on lithium), and possibly cognitive problems (these are not well studied, but appear to be dose-dependent on lithium).
—Chris Aiken, MD
Director, Psych Partners
Editor in Chief, Carlat Psychiatry Report
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- Does this match your experience with lithium?
