Types of Antidepressants

Medically Reviewed by Jabeen Begum, MD on June 07, 2024
13 min read

Everybody's different — and everyone's depression is different, too. If you and your doctor decide to try antidepressant medications to help treat your depression, you’ll work together to find one that works.

There are several types of antidepressants. So, it may take some trial and error until you find one that's a good fit for your symptoms, but it's important to understand that you won’t see results right away. Antidepressants take up to several weeks before they have their full effect and you see a difference in your symptoms. 

Also keep in mind that depression treatment tends to have the best results when it’s combined with counseling (“talk therapy”) and lifestyle changes, such as getting regular exercise. You and your doctor should talk about that. What you need depends on how depressed you are, the type of depression you have, your medical history, and whether you’ve used antidepressants before.

If you don’t have a counselor or qualified therapist, ask your doctor for a referral. Your friends and family may also have recommendations. You could also check with your insurance company or employer, who may have an Employee Assistance Program (EAP).

There are several types of antidepressants available, but people react differently to different drugs. One type of antidepressant that works well for one person may not be as effective for you. The right one for you can help lift your mood and ease the sadness and hopelessness you might feel while causing minimal or no side effects. Some people need to take more than one type of antidepressant before they start to feel better. This isn’t unusual.

The following are the different types of antidepressants your doctor can choose.

SSRIs are the most commonly prescribed antidepressants. They are usually the first choice to treat depression.

SSRI mechanism of action

Serotonin, a neurotransmitter that delivers messages to your brain, helps regulate many body functions, including your mood and social behavior. After serotonin delivers its message, it usually gets absorbed into the brain. But your brain needs a certain level of serotonin to work efficiently. If your levels drop, this can cause depression. SSRIs stop the brain from absorbing serotonin, thus increasing its levels.

Possible side effects of SSRIs

SSRIs are popular because they work well and tend to have fewer side effects than other types of antidepressants. The most common side effects include:

  • Difficulty sleeping
  • Headaches
  • Weight changes
  • Worsening anxiety
  • Dizziness
  • Nausea and vomiting
  • Dry mouth (also called xerostomia)
  • Sexual dysfunction

SSRI drug interactions

When taking any medication, it’s vital that all your doctors know what other medications you take, no matter who prescribed them. Some drugs should never be taken together or must be used carefully. For example, if you take an SSRI, it’s important not to take other medications that also increase serotonin levels. This can lead to a serious complication called serotonin syndrome.

The drugs that are most likely to cause serotonin syndrome when combined with SSRIs are other antidepressants, especially monoamine oxidase inhibitors (MAOIs) and the antibiotic linezolid. However, there are other drugs that could also increase serotonin levels or affect how well SSRIs work. They include:

  • Antinausea medications
  • Bupropion (antidepressant, smoking cessation drug)
  • Illicit drugs (amphetamines, cocaine ecstasy, and LSD)
  • Lithium (to treat bipolar disorder)
  • Over-the-counter drugs that contain dextromethorphan (to treat colds and coughs)
  • Ritonavir (to treat HIV)
  • Some pain medications, especially opioids
  • Some antimigraine medications
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Aspirin
  • Anticoagulants, also called blood thinners

Who should not take SSRIs

While SSRIs are relatively safe, some people shouldn't take SSRIs. You should avoid SSRIs if you take other medications that increase serotonin or if you’re pregnant, especially in the first trimester. 

Top SSRIs to treat depression

There are several types of SSRIs that your doctor can prescribe. The ones in the U.S. are:

  • Citalopram (Celexa)
  • Escitalopram (Lexapro)
  • Fluoxetine (Prozac)
  • Fluvoxamine (Luvox)
  • Sertraline (Zoloft)

SNRIs are similar to SSRIs, differing mainly in their mechanism of action.

SSRI mechanism of action

Like SSRIs, SNRIs increase serotonin, but they also increase norepinephrine, another neurotransmitter. Together, the two neurotransmitters regulate many of your body functions, such as your mood, how well you sleep, and your social behavior. Norepinephrine also plays a role in how alert you are. For some people, SSRIs aren’t quite enough, and switching to an SNRI gives them the extra help they need.

SNRI side effects

Some of the possible SNRI side effects are the same as those for SSRIs, such as nausea, dry mouth, dizziness, sleep problems, sexual dysfunction, and headache. Other possible side effects include:

  • Excessive sweating
  • Fatigue
  • Constipation
  • Loss of appetite

While not common, some SNRIs could also cause your blood pressure to go up, and one in particular, duloxetine, may cause liver problems.

SNRI drug interactions

SNRIs mixed with other drugs that raise serotonin levels can cause serotonin syndrome. Also, if your doctor wants to prescribe an SNRI, be sure to mention if you take drugs that can increase your bleeding risk, such as aspirin or anticoagulants. Combined with an SNRI, these drugs can increase your bleeding risk even more.

Who should not take SNRIs

You shouldn’t take an SNRI if you take other medications that increase serotonin or if you’re pregnant, especially in the first trimester.

Top SNRIs to treat depression

The most commonly prescribed SNRIs include:

  • Desvenlafaxine (Pristiq)
  • Duloxetine (Cymbalta)
  • Levomilnacipran (Fetzima)
  • Venlafaxine (Effexor)

Tricyclic antidepressants (TCAs) were among the first drugs developed to treat depression. They’ve been on the market since the 1950s.

TCA mechanism of action

Like SNRIs, TCAs increase available serotonin and norepinephrine for people who need more.

Possible side effects of TCAs

Although TCAs manage depression much the same way as SNRIs, they affect more neurotransmitters — not just serotonin and norepinephrine. This means there are more possible side effects and it’s why TCAs aren’t usually the first choice for treating depression. Some of the side effects are similar to those of SSRIs and SNRIs, such as constipation, dry mouth, and dizziness. However, TCAs may also cause:

  • Urine retention (inability to pee)
  • Blurry vision
  • Rapid heartbeat
  • Drop in blood pressure when standing up, called orthostatic hypotension
  • Increased appetite
  • Weight gain

TCA drug interactions

People who take TCAs shouldn’t take other types of antidepressants, especially MAOIs at the same time. If you already take an MAOI and your doctor wants to switch you to a TCA, experts recommend that you wait 2 weeks from your last MAOI dose before starting a TCA. However, your doctor’s recommendations will be based on your particular situation.

Who should not take TCAs

Some people shouldn’t take TCAs to treat their depression because of possible complications. You shouldn’t take a TCA if you:

  • Have a family history of a heart problem called QTc interval prolongation (also called Long QT syndrome) or sudden cardiac death
  • Had an allergic reaction to any TCA

TCAs may be used carefully if you have one of these conditions and your doctor believes that the benefits outweigh the risks. 

Top TCAs to treat depression

TCAs in the U.S. include:

  • Amitriptyline (Elavil)
  • Amoxapine (Asendin)
  • Desipramine (Norpramin)
  • Doxepin (Sinequan)
  • Imipramine (Tofranil)
  • Nortriptyline (Aventyl, Pamelor)
  • Protriptyline (Vivactil)
  • Trimipramine (Surmontil)

Monoamine oxidase inhibitors are the oldest antidepressants available in the U.S. The newer antidepressants, such as SSRIs and SNRIs, have fewer side effects, so MAOIs aren’t used as often anymore. However, if SSRIs, SNRIs, and TCAs don’t work, MAOIs might.

MAOI mechanism of action

This group of drugs works on the brain differently than the other types of antidepressants. You have an enzyme called monoamine oxidase in your brain. Its job is to remove serotonin and norepinephrine, as well as another neurotransmitter called dopamine. MAOIs inhibit or stop the enzyme from doing that. By having extra serotonin, norepinephrine, and dopamine, your depression might be treated.

Possible side effects of MAOIs

Like other antidepressants, some MAOI side effects include:

  • Drowsiness
  • Insomnia
  • Dry mouth
  • Nausea
  • Diarrhea
  • Constipation
  • Dizziness, lightheadedness
  • Sexual dysfunction
  • Weight gain

Other MAOI side effects can include:

  • Skin irritation if the dose is given through a skin patch
  • Jerking muscles
  • Muscle cramps
  • A feeling of tingling or prickling on the skin (paresthesia)
  • Low blood pressure
  • Difficulty starting to urinate

MAOI drug interactions: People taking an MAOI shouldn’t take an SSRI, SNRI, or TCA at the same time because it can cause serotonin syndrome. Other drugs that should be avoided with MAOIs are:

  • Bupropion
  • Dextromethorphan
  • Meperidine
  • Methadone
  • Mirtazapine
  • Tramadol
  • St. John’s Wort
  • Sympathomimetic amines (stimulants), such as epinephrine and dopamine

If you take an MAOI, you must also avoid some types of foods, those that contain a natural compound called tyramine. Eating foods high in tyramine while taking an MAOI can cause dangerously high blood pressure. This list contains examples of foods you should avoid while taking an MAOI, but it is not complete. Speaking with a dietician can help you adapt your diet and learn how to identify high-tyramine foods.

  • Aged cheeses, such as parmesan
  • Cured, processed, smoked meats and fish, including salami, hot dogs, and smoked fish
  • Pickled/fermented foods, such as kimchi, pickles, pickled herring, or tofu
  • Certain sauces, such as soy sauce, miso sauce, or teriyaki sauce
  • Soybeans and associated products such as soy sauce
  • Fava beans
  • Foods with yeast extract, such as sourdough bread or Marmite
  • Alcohol, especially beer
  • Dried or overripe fruits
  • Foods with meat tenderizers
  • Leftover or spoiled foods

If you take any over-the-counter supplements, check for tyramine too.

Who should not take MAOIs

There are several groups of people who should avoid MAOIs. You should not take an MAOI if you have:

  • A history of alcoholism
  • Angina
  • Blood vessel disease
  • Diabetes
  • Kidney disease
  • Liver disease
  • Had a recent heart attack
  • Recent stroke
  • Hyperthyroid (overactive thyroid)
  • Pheochromocytoma

MAOIs should be avoided if possible if you have a family history of:

  • Depression
  • Neurological disorder
  • Suicide attempts

Top MAOIs to treat depression

These three MAOIs are taken in pill form:

  • Isocarboxazid (Marplan)
  • Phenelzine (Nardil)
  • Tranylcypromine (Parnate)

Selegiline (Emsam) is given by a patch on the skin.

If your depression is resistant to other kinds of antidepressants (the drugs don’t work for you) or you have had side effects that you can’t tolerate, your doctor may recommend an atypical antidepressant. These types of antidepressants are called atypical because they don’t fit into the other categories of antidepressants.

Atypical antidepressant mechanism of action

The mechanism of action for atypical antidepressants depends on the drug. Like the other antidepressants, they affect the levels of serotonin, norepinephrine, or dopamine.

Possible side effects of atypical depressants

Their side effects are much the same as SSRIs, SNRIs, and CTAs.

Atypical antidepressant drug interactions

Because some of the atypical antidepressants increase serotonin, you should avoid other drugs that also increase serotonin because they can lead to serotonin syndrome. This includes other antidepressants.

Who should not take atypical antidepressants?

Each drug has its own safety risks. If you:

  • Have a seizure disorder or eating disorder, you should not take bupropion.
  • Have liver disease, you should not take nefazodone.
  • Take anticoagulants or other medications that can increase bleeding risk, you should use vilazodone and vortioxetine with caution.

Top atypical antidepressants to treat depression

These atypical antidepressants are approved for use in the U.S.:

  • Bupropion (Wellbutrin)
  • Mirtazapine (Remeron)
  • Nefazodone
  • Trazodone
  • Vilazodone (Viibryd)
  • Vortioxetine (Trintellix)

Some drugs that were first used to treat schizophrenia, called atypical antipsychotics, may also help certain kinds of depression, either alone or in combination with more traditional antidepressants.

Some examples are:

  • Aripiprazole (Abilify)
  • Brexpiprazole (Rexulti)
  • Lurasidone (Latuda)
  • Olanzapine-fluoxetine combination (Symbyax)
  • Quetiapine (Seroquel)

Over time, doctors have learned that antidepressants can treat other conditions as well as depression. These conditions include:

  • Bipolar depression
  • Bulimia
  • Chronic pain
  • Obsessive-compulsive disorder
  • Panic disorder
  • Posttraumatic stress disorder (PTSD)
  • Social anxiety disorder

Aside from possible side effects, antidepressants can cause some serious complications.

Suicidal thoughts or behavior

Young adults (under 25), teens, and children are at risk for suicidal thoughts or behaviors, especially when first starting the medication or when the dose has changed. If you or someone you know experience any suicidal thoughts or behaviors, call your doctor immediately, go to an emergency department, or call 911 or the Suicide and Crisis Lifeline at 988.

Antidepressant discontinuation syndrome

Often called withdrawal, antidepressant discontinuation syndrome can happen if you’ve taken an antidepressant for more than 6 weeks and then suddenly stop. Experts use the word “finish” to help remember the signs and symptoms:

  • F for flu-like symptoms, such as fatigue, headache, muscle aches
  • I for insomnia, which can also have vivid dreams or nightmares
  • N for nausea and vomiting
  • I for imbalance, so dizziness or lightheadedness
  • S for sensory disturbances, feeling burning, tingling, or shock-like sensations
  • H for hyperarousal, feeling agitated, aggressive, irritable

Serotonin syndrome

Although rare, serotonin syndrome is a serious complication caused by having too much serotonin in your body. This is why it’s vital to not take any other drugs that raise serotonin along with your antidepressant. Symptoms include:

  • Hyperarousal, agitation, or restlessness
  • Confusion
  • Insomnia
  • Rapid heartbeat
  • High blood pressure
  • Dilated pupils
  • Twitching muscles, muscle rigidity
  • Loss of coordination
  • Heavy sweating
  • Diarrhea
  • Headache
  • Shivering
  • Goosebumps


Antidepressant overdoses can occur by accident or intentionally. An overdose is a medical emergency. If you suspect someone has overdosed on antidepressants, call 911 for emergency help.

The signs and symptoms of an antidepressant overdose depend on the type of antidepressant and how serious the overdose is. Any overdose can cause death, but it’s more common for TCA. Signs and symptoms of a TCA overdose include:

  • Changes in your heart rhythm
  • Drop in blood pressure (hypotension)
  • Drowsiness
  • Confusion, change in mental status
  • Rigid muscles
  • Coma

SSRI overdose can cause:

  • High blood pressure
  • Heart arrhythmias (abnormalities)
  • Seizures

SNRI overdose can cause:

  • Nausea
  • Vomiting
  • Diarrhea
  • Sweating
  • Agitation
  • Confusion
  • Muscle rigidity
  • Dilated (widened) pupils 
  • Shivering
  • High fever
  • Seizures
  • Irregular heartbeat
  • Coma

MAOI overdose can cause:

  • Severely high fever
  • Seizures
  • Depression (slowing down) of the:
    • Central nervous system
    • Respiratory system
    • Cardiac system
  • Rigid muscles
  • Involuntary twitching (myoclonus)

Mania and hypomania

More research is needed but there are reports that some people who use antidepressants may develop mania or bipolar disorder. Antidepressant treatment should always be done with a doctor’s supervision. If you are taking antidepressant medication, report any changes in your behavior or thought processes to your doctor as soon as possible so you can be assessed properly.

Choosing the right type of antidepressant is something that you do with your doctor, as a team. Your doctor will have an opinion on what is the right antidepressant for you, but you must also stay in contact with your doctor after you start taking it. You should report any changes, better or worse, so your doctor can determine if the medication is working for you.

Here are some things that your doctor will take into consideration when choosing an antidepressant:

  • If it’s the first time you’re taking an antidepressant or if you need to replace one that isn’t working or causing too many side effects
  • What type of depression you have
  • If you have a history of suicidal thoughts
  • If you have any other medical problems, such as chronic pain or you take blood thinners
  • Your preference, such as wanting to avoid a medication that might cause weight gain

Research into gene testing for treating moderate-to-severe depression is promising. The goal of the testing is to find which medications you are more likely to respond to based on your genes.

There are many types of antidepressants that could help you if you live with depression. Most often, doctors start with SSRIs because they are effective and generally have fewer side effects than the other types of antidepressants. It can take some time to find the antidepressant that works for you and sometimes, people must take two different ones for the best results. Stay in touch with your doctor while you take antidepressants so you can report any side effects, and if the drug seems to be helping or not.


What are some of the top antidepressants?

The top antidepressants, the ones most commonly used, are SSRIs, especially fluoxetine, citalopram, sertraline, paroxetine, and escitalopram.

Is depression treatable?

Depression is a treatable disease. It can be treated with one of many types of antidepressants, but it usually responds better to a wider approach, including counseling and lifestyle changes.

Which is the most effective SSRI for depression?

All SSRIs are effective for depression — one is not better than the other. How well they work depends on the person and how their body responds to the drug. Some people respond well to one type of SSRI but not to another. Other people don’t respond to SSRIs at all and must try a different type of antidepressant.

What are the 4 main groups of antidepressants?

The four main groups of antidepressants are:

  • SSRIs
  • SNRIs
  • CTAs
  • MAOIs