For example, peroxisome proliferator-activated receptor (PPAR)-γ agonists target insulin resistance and the related oxidative and pro-inflammatory changes (which are also involved in the pathogenesis of depressive symptoms); they were demonstrated to have antidepressant effects in patients with treatment-resistant bipolar depression and concomitant insulin resistance (Kemp et al., 2014). This evidence concerns the gene PPARG and bipolar disorder.