Depression is a common and significant health problem associated with impairment in a patient's ability to function. The development of new antidepressant medications represents progress in its treatment. These new agents work through the selective blockade of the reuptake of serotonin into the presynaptic neuron, thereby increasing the availability of this neurotransmitter at the synaptic cleft and enhancing its effectiveness. While no more effective than traditional tricyclic antidepressant drugs, the new agents are generally safer than traditional medications used to treat depression: they are well tolerated and, in case of overdose, less harmful than tricyclic antidepressants.