GADL1 variant and medication adherence in predicting response to lithium maintenance treatment in bipolar I disorder

Background Genetic variants and medication adherence have been identified to be the main factors contributing to lithium treatment response in bipolar disorders. Aims To simultaneously examine effects of variant glutamate decarboxylase-like protein 1 (GADL1) and medication adherence on response to lithium maintenance treatment in Han Chinese patients with bipolar I (BPI) disorder. Method Frequencies of manic and depressive episodes between carriers and non-carriers of the effective GADL1 rs17026688 T allele during the cumulative periods of off-lithium, poor adherence to lithium treatment and good adherence to lithium treatment were compared in Han Chinese patients with BPI disorder (n = 215). Results GADL1 rs17026688 T carriers had significantly lower frequencies of recurrent affective episodes than non-T carriers during the cumulative period of good adherence, but not during those of poor adherence. Conclusions GADL1 rs17026688 and medication adherence jointly predict response to lithium maintenance treatment in Han Chinese BPI patients.