APA Dictionary of Psychology

an antidepressant that acts primarily via more than one major neurotransmitter system. The term is often applied to the SNRIs (e.g., venlafaxine), which inhibit the reuptake of both norepinephrine and serotonin, to distinguish them from the SSRIs (selective serotonin reuptake inhibitors). Also called dual-action antidepressant; mixed-function antidepressant.