Long term use of lithium and factors associated with treatment response among patients with bipolar disorder.

BACKGROUND Lithium has been the gold standard in treating bipolar disorder. In recent years, the use of lithium seems to be diminished although it is well tolerated among the bipolar disorder patients. SUBJECTS AND METHODS This study aimed to evaluate the efficacy and tolerability of lithium as well as to determine factors associated with lithium response among patient with bipolar disorder. A retrospective study was done in a tertiary care hospital in Malaysia which included 47 bipolar disorder patients that were prescribed with lithium maintenance therapy in the time frame of January 2009 until December 2013. RESULTS Of all the baseline characteristics tested, only psychotic feature differentiated lithium monotherapy group and combination therapy group significantly (χ(2)=4.732, p=0.03). When compared to period before lithium maintenance, all outcome measures (i.e. annual relapse rate, proportion time spent ill and duration of mood episode) showed significant improvement after lithium maintenance in both treatment groups. Lithium discontinuation only occurred in five cases of adverse effects. Predominant depressive mood episode before lithium maintenance (OR=0.159, p=0.033) and first euthymic interval after lithium maintenance (OR=1.109, p=0.047) significantly predicted lithium response. DISCUSSION Lithium significantly reduced the frequency and time spent in relapse in patients with bipolar disorder. Predominant depressive mood polarity before lithium maintenance and longer first euthymic interval after lithium maintenance had been identified to predict lithium response significantly.