Brain cells called astrocytes derived from the induced pluripotent stem cells of patients with bipolar disorder offer suboptimal support for neuronal activity. In a paper appearing March 4th in the journal Stem Cell Reports, researchers show that this malfunction can be traced to an inflammation-promoting molecule called interleukin-6 (IL-6), which is secreted by astrocytes. The results highlight the potential role of astrocyte-mediated inflammatory signaling in the psychiatric disease, although further investigation is needed.