Understanding microglial involvement in stress-induced mood disturbance: a modulator of vulnerability?

•Neuroimmune signals generated by microglia are involved in the pathogenesis of mood disorders.•Increasingly, models of stress-induced mood disorder consider individual susceptibility or resilience to the behavioural effects of stress.•A number of candidate neuroimmune mechanisms have been identified that may mediate vulnerability to chronic stress.•Microglial priming, synaptic plasticity, glutamatergic neurotransmission, and blood brain barrier dysfunction are potential contributors.•Future work should consider the role of microglia within neural networks, and expand our understanding of susceptibility or resilience to stress.