Risk factors for early recurrence after discontinuing lithium in bipolar disorder
Ross J. Baldessarini, Marco Pinna, Martina Contu, Gustavo Vázquez, Leonardo Tondo
Abstract
BACKGROUND: Time to a new episode of bipolar disorder (BD) is shorter after discontinuing lithium rapidly. We now address this and other factors associated with the risk of early illness after discontinuing lithium. METHODS: We compared factors for association with recurrences of BD within 12 months of discontinuing long-term lithium treatment, using bivariate and multivariable analyses, as well as survival analysis to evaluate latency to new episodes versus rate of lithium-discontinuation and prior treatment duration. RESULTS: Among 227 BD subjects who received lithium for 4.47 [CI: 3.89-5.04] years and then discontinued, rapid treatment-discontinuation, and stopping for medical reasons were strongly associated with new illness-episodes within 12 months, as were diagnosis (BD-I > BD-II), greater morbidity during lithium-treatment, and less education, but neither longer treatment nor serum lithium concentrations. Discontinuation rate was strongly associated with shorter median latency to a new episode (rapid: 3.50; gradual [≥2 weeks]: 10.6 months), even with very early recurrences excluded to avoid potential contributions of emerging illness to treatment-discontinuation. Early recurrence was not associated with treatment-duration of ≥2 or ≥5 years or less. In multivariable logistic regression, rapid discontinuation, stopping for medical reasons, and BD-I diagnosis remained significantly, independently associated with early illness after lithium-discontinuation, with no effect of treatment duration. CONCLUSIONS: Early recurrence risk was again much greater after rapid discontinuation of lithium and discontinuing for medical reasons, somewhat greater with BD-I than BD-II, and following greater morbidity during lithium-treatment, but not related to dose or duration of preceding treatment exposure.