We investigated the effect of reboxetine, a selective noradrenaline reuptake inhibitor, 7 days after treatment with subchronic lithium on extracellular noradrenaline, dopamine and serotonin (5-HT) concentrations in the medial prefrontal cortex. Acute treatment with reboxetine significantly increased extracellular concentrations of noradrenaline and dopamine, but did not alter 5-HT concentrations. Subchronic lithium increased basal levels of extracellular 5-HT, but not noradrenaline or dopamine. Co-administration of reboxetine and lithium treatment increased the extracellular concentrations of noradrenaline, dopamine and 5-HT, though reboxetine alone increased the extracellular levels of noradrenaline and dopamine only. Thus, combined lithium and reboxetine produces an additive effect neurochemically rather than their interaction.