Three patients suffering from a treatment-resistant depression were being treated with a monoamine oxidase (mao-)inhibitor and received lithium augmentation to achieve better recovery. One patient showed significant improvement of depressive symptoms within 24 hours, one patient showed very little respons and one patient did not respond at all. Literature research led to other casereports, where adding lithium to mao-inhibitors had also been effective. The growing amount of arguments of a positive effect of lithium augmentation to mao-inhibitors asks for more research to collect more evidence and a better understanding of this new, potentially effective treatment.