It is more popular. Serzone is chemically different from selective serotonin reuptake inhibitor (SSRI) and monoamine oxidase inhibitor (MAOI) antidepressants. It inhibits the uptake of serotonin and norepinephrine and blocks one type of serotonin receptor. It is thought that this blocking effect greatly decreases the insomnia, weight gain and lack of sexual interest common in patients taking other antidepressants.