1. There are 5 classes of antidepressants: tricyclic and tetracyclic antidepressants, selective serotonin reuptake inhibitors, monoamine oxidase inhibitors, selective serotonin-norepinephrine reuptake inhibitors, and dopamine norepinephrine reuptake inhibitors. 2. Tricyclic and tetracyclic antidepressants work by blocking the reuptake of serotonin and norepinephrine and have indications for major depressive disorder, panic disorder, and others but can cause anticholinergic side effects. 3. Selective serotonin reuptake inhibitors like fluoxetine, sertraline selectively inhibit serotonin reuptake, have fewer side effects than tricyclics, and are widely used for conditions like