Depression is a mental health issue that starts most often in early adulthood. It’s also more common in women. However, anyone at any age may deal with depression.

Depression affects your brain, so drugs that work in your brain may prove beneficial. Common antidepressants may help ease your symptoms, but there are many other options as well. Each drug used to treat depression works by balancing certain chemicals in your brain called neurotransmitters. These drugs work in slightly different ways to ease your depression symptoms.

Many common drugs fall into the following drug classes:

  • selective serotonin reuptake inhibitors (SSRIs)
  • serotonin and norepinephrine reuptake inhibitors (SNRIs)
  • tricyclic antidepressants (TCAs)
  • tetracyclic antidepressant
  • dopamine reuptake blocker
  • 5-HT1A receptor antagonist
  • 5-HT2 receptor antagonists
  • 5-HT3 receptor antagonist
  • monoamine oxidase inhibitors (MAOIs)
  • noradrenergic antagonist

Atypical antidepressants, which don’t fall into these drug classes, and natural treatments such as St. John’s wort are also available.

Read on to learn more about how all of these drugs work and their potential side effects.

SSRIs are the most commonly prescribed class of antidepressants. An imbalance of serotonin may play a role in depression. These drugs fight depression symptoms by decreasing serotonin reuptake in your brain. This effect leaves more serotonin available to work in your brain.

SSRIs include:

  • sertraline (Zoloft)
  • fluoxetine (Prozac, Sarafem)
  • citalopram (Celexa)
  • escitalopram (Lexapro)
  • paroxetine (Paxil, Pexeva, Brisdelle)
  • fluvoxamine (Luvox)

Common side effects of SSRIs include:

  • nausea
  • trouble sleeping
  • nervousness
  • tremors
  • sexual problems

Learn more: What you should know about selective serotonin reuptake inhibitors (SSRIs) »

SNRIs help improve serotonin and norepinephrine levels in your brain. This may reduce depression symptoms. These drugs include:

  • desvenlafaxine (Pristiq, Khedezla)
  • duloxetine (Cymbalta)
  • levomilnacipran (Fetzima)
  • venlafaxine (Effexor XR)

In addition to treating depression, duloxetine may also relieve pain. This is important because chronic pain can lead to depression or make it worse. In some cases, people with depression become more aware of aches and pains. A drug that treats both depression and pain, such as duloxetine, can be helpful to these people.

Common side effects of SNRIs include:

  • nausea
  • drowsiness
  • fatigue
  • constipation
  • dry mouth

TCAs are often prescribed when SSRIs or other antidepressants don’t work. It isn’t fully understood how these drugs work to treat depression.

TCAs include:

  • amitriptyline
  • amoxapine
  • clomipramine (Anafranil)
  • desipramine (Norpramin)
  • doxepin
  • imipramine (Tofranil)
  • nortriptyline (Pamelor)
  • protriptyline
  • trimipramine (Surmontil)

Common side effects of TCAs can include:

  • constipation
  • dry mouth
  • fatigue

The more serious side effects of these drugs include:

  • low blood pressure
  • irregular heart rate
  • seizures

Learn more: Tricyclic antidepressants »

Maprotiline is used to treat depression and anxiety. It also works by balancing neurotransmitters to ease symptoms of depression.

Common side effects of this drug include:

  • drowsiness
  • weakness
  • lightheadedness
  • headache
  • blurry vision
  • dry mouth

Bupropion (Wellbutrin, Forfivo, Aplenzin) is a mild dopamine and norepinephrine reuptake blocker. It’s used for depression and seasonal affective disorder. It’s also used in smoking cessation.

Common side effects include:

  • nausea
  • vomiting
  • constipation
  • dizziness
  • blurry vision

The drug in this class that’s used to treat depression is called vilazodone (Viibryd). It works by balancing serotonin levels and other neurotransmitters.

This drug is rarely used as a first-line treatment for depression. That means it’s usually only prescribed when other medications didn’t work for you or caused bothersome side effects.

Side effects can include:

  • nausea
  • vomiting
  • trouble sleeping

Two 5-HT2 receptor antagonists, nefazodone and trazodone (Oleptro), are used to treat depression. These are older drugs. They alter chemicals in your brain to help depression.

Common side effects include:

  • drowsiness
  • dizziness
  • dry mouth

The 5-HT3 receptor antagonist vortioxetine (Brintellix) treats depression by affecting the activity of brain chemicals.

Common side effects include:

  • sexual problems
  • nausea

MAOIs are older drugs that treat depression. They work by stopping the breakdown of norepinephrine, dopamine, and serotonin. They’re more difficult for people to take than most other antidepressants because they interact with prescription drugs, nonprescription drugs, and some foods. They also can’t be combined with stimulants or other antidepressants.

MAOIs include:

  • isocarboxazid (Marplan)
  • phenelzine (Nardil)
  • selegiline (Emsam), which comes as a transdermal patch
  • tranylcypromine (Parnate)

MAOIs also have many side effects. These can include:

  • nausea
  • dizziness
  • drowsiness
  • trouble sleeping
  • restlessness

Mirtazapine (Remeron) is used primarily for depression. It alters certain chemicals in your brain to ease depression symptoms.

Common side effects include:

  • drowsiness
  • dizziness
  • weight gain

Other depression drugs don’t fall into the typical classes. These are called atypical antidepressants. Depending on your condition, your doctor may prescribe one of these alternatives instead.

For example, olanzapine/fluoxetine (Symbyax) is an atypical antidepressant. It’s used to treat bipolar disorder and major depression that doesn’t respond to other drugs.

Ask your doctor if an alternative drug treatment is a good choice for you. They can tell you more.

Keep reading: Best atypical antipsychotics for treating depression »

You may be interested in natural options to treat your depression. Some people use these treatments instead of drugs, and some use them as an add-on treatment to their antidepressant medication.

St. John’s wort is an herb that some people have tried for depression. According to the National Center of Complementary and Integrative Health, the herb may have mild positive effects, or it may not work any better than placebo. This herb also causes many drug interactions that can be serious.

St. John’s wort interacts with:

  • antiseizure drugs
  • birth control pills
  • warfarin (Coumadin)
  • prescription antidepressants

Also, certain drugs for depression may not work as well if you take them with St. John’s wort.

The supplement S-adenosyl-L-methionine (SAMe) is another natural option that some people have tried to ease their depression symptoms. SAMe may help treat joint pain, but there’s not much support to show that it helps with depression. This treatment can also interact with prescription drugs.

Get more info: Is St. John’s wort safe? »

When it comes to treating depression, what works for one person may not work for another. Finding the right drug for your depression can take time.

If you start taking medication for your depression, allow time for trial and error. According to the Mayo Clinic, it can take at least six weeks for an antidepressant to work fully.

Ask your doctor how long it should take for your medication to work. If your symptoms of depression haven’t improved by then, talk to your doctor. They may suggest another medication that may be more effective in relieving your depression.