Plasma levels of leptin and endogenous immune modulators during treatment with carbamazepine or lithium

Several psychopharmacological agents induce weight gain. Recent studies have suggested that the tumor necrosis factor-alpha (TNF-alpha) cytokine system is pathophysiologically involved. To assess whether carbamazepine and lithium, which have been reported to lead to weight gain, have effects on the circulating levels of cytokines, we measured plasma levels of TNF-alpha, its soluble receptors sTNF-R p55 and p75, and leptin, as well as weight in 25 inpatients receiving lithium (n=10) or carbamazepine (n=15) weekly during the first 4 weeks of treatment. We found an increase in the body mass index and in TNF-alpha and its soluble receptor levels, but not in leptin levels over the 4 weeks of treatment. These changes did not differ between treatment groups. Changes of weight during the first week of treatment, but no other parameter, strongly predicted weight change until endpoint. We conclude that the mood stabilizers carbamazepine and lithium have similar effects on the TNF-alpha system and do not affect leptin levels.