Effect of catecholamine depletion on lithium-induced long-term remission of bipolar disorder

Background: This study investigated the effects of catecholamine depletion with alpha-methylparatyrosine (AMPT) on mood indices in. patients with bipo lar disorder who were in long-term remission with lithium therapy. Methods: Eight subjects with DSM-IV bipolar disorder currently in remission for >3 months on lithium were included in the study. Subjects were given e ither AMPT or placebo, in a randomized double-blind manner, in two test ses sions of 4 days each. Results: Subjects did not have arty significant changes in mood during AMPT or placebo administration; however, 24-48 hours after the last active AMPT dose subjects had a transient I-elapse of hypomanic symptoms. Relapse of h ypomanic symptoms did not correlate with increases in serum levels of homov anillic acid or 3-methoxy-4-hydroxyphenylglycol. Conclusions: These findings suggest that the mechanism of prevention of man ic relapse by long-term lithium therapy may be dependent on stability of th e catecholamine system. (C) 1999 Society of Biological Psychiatry.