In cases of severe depression, medication can be helpful in managing symptoms. Antidepressants work by targeting specific neurotransmitters linked to mood and increase their levels in the brain. The first choices of medications for severe depression are selective and dual reuptake inhibitors, such as selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), and norepinephrine and dopamine reuptake inhibitors (NDRIs). Patients may need to try different antidepressants, under the supervision of their doctors, to find the right medication.
Selective Serotonin Reuptake Inhibitors (SSRIs)
The Mayo Clinic states that SSRIs are often used to treat serious depression, as these medications are effective in reducing symptoms and have few side effects. SSRIs affect only the neurotransmitter serotonin, which has been linked to mood. In the brain, serotonin is reabsorbed when it is not used; SSRIs prevent this reuptake, keeping more serotonin available for use by the brain. More neurotransmission occurs when a patient takes an SSRI, which improves her mood. The FDA has approved citalopram, escitalopram, fluoxetine, paroxetine and sertraline for the treatment of depression. The effects of SSRIs are not immediate; it can take four to six weeks for the medication to start treating the symptoms of severe depression.
Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs)
SNRIs are a form of dual reuptake inhibitor that is prescribed for severe depression. The Mayo Clinic notes that SNRIs affect two neurotransmitters: serotonin and norepinephrine; increased levels of norepinephrine also improve a depressed patient's mood. Because SNRIs prevent the reuptake of serotonin and norepinephrine, these medications have different pharmacological effects when compared to SSRIs. Two types of SNRIs are approved for depression treatment by the FDA: duloxetine and venlafaxine. Like SSRIs, SNRIs take a few weeks to go into effect.
Norepinephrine and Dopamine Reuptake Inhibitors (NDRIs)
NDRIs are a third type of antidepressant medication that specifically targets neurotransmitters. NDRIs do not interfere in the levels of serotonin; instead, they alter the levels of norepinephrine and dopamine. Another neurotransmitter related to mood, dopamine is the precursor of norepinephrine. The Mayo Clinic states that as of November 2009, bupropion is the only NDRI approved by the FDA for depression treatment. Bupropion is available in three forms based on its release: extended-release, slow-release and immediate-release. Patients who use immediate-release bupropion take three doses, while patients who use slow-release buproprion take two doses; extended-release bupropion users need only one pill a day.
