In line with these studies, a recent PET imaging study in subjects with bipolar depression found a strong correlation of low pretreatment 5-HT1A binding (particularly in amygdala, hippocampus, and parahippocampal gyrus, but not dorsal raphe) with a better remission rate following 8-week lithium treatment [62], suggesting that a greater capacity for lithium up-regulation in low 5-HT1A patients might improve treatment outcome. This evidence concerns the gene HTR1A and bipolar disorder.