Antidepressants can help relieve the symptoms of depression and anxiety. Common examples include selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine (Prozac), and serotonin-norepinephrine reuptake inhibitors (SNRIs), such as duloxetine (Cymbalta).

Antidepressants work by increasing neurotransmitters in the brain. Experts believe these brain chemicals are responsible for changes in mood and behavior.

This article covers the types of antidepressants, how they work, their side effects, other uses, and alternative options.

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Doctors tend to divide antidepressants into different types. These include:

Selective serotonin reuptake inhibitors (SSRIs)

SSRIs are a first-line treatment option for depression.

Examples of SSRIs include:

Serotonin-norepinephrine reuptake inhibitors (SNRIs)

SNRIs are a newer class of antidepressants compared with SSRIs. However, they work similarly.

Doctors may prescribe SNRIs for:

Examples of SNRIs include:

Tricyclic antidepressants (TCAs)

Doctors may recommend TCAs for:

Examples of TCAs include:

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

Monoamine oxidase inhibitors (MAOIs)

Due to their adverse side effects and drug interactions, doctors do not typically suggest MAOIs as a first-line treatment option for depression. However, they may be an option in the case of treatment-resistant depression.

Examples include:

  • phenelzine (Nardil)
  • tranylcypromine (Parnate)
  • isocarboxazid (Marplan)
  • selegiline (Emsam, Eldepryl)

Noradrenaline and specific serotoninergic antidepressants (NaSSAs)

Doctors prescribe NaSSAs to treat anxiety disorders and depression.

Examples include mirtazapine (Remeron, Avanza, Zispin) and mianserin (Tolvon). Mianserin is not available in the United States.

All drugs have side effects, not just antidepressants.

Different antidepressants have different side effects. However, not everyone experiences them.

SSRI and SNRI side effects

SSRIs and SNRIs can lead to:

SNRIs can also increase blood pressure. A person with a serious heart condition should not take the SNRI venlafaxine.

TCA side effects

TCAs may have the following side effects:

MAOI side effects

MAOIs can interact with other drugs. For example, if a person combines an MAOI with an SSRI, it could lead to serotonin syndrome. Serotonin syndrome is a serious condition in which a person has too much serotonin in their body.

MAOIs can also lead to:

MAOIs prevent the breakdown of tyramine. If a person consumes foods that contain tyramine, such as sausages, dried fish, and overripe fruit, it can lead to a hypertensive crisis. This is a severe increase in blood pressure that can lead to a stroke.

NaSSA side effects

These antidepressants can lead to side effects similar to SSRIs and SNRIs. NaSSAs can also cause drowsiness and weight gain. They are less likely to cause sexual dysfunction.

Rarer side effects

Rarer side effects of antidepressants include:

  • Suicidal thoughts: According to the United Kingdom’s National Health Service (NHS), young adults and children may have a higher risk of suicidal thoughts when they first start taking antidepressants. If side effects are very unpleasant or include thinking about suicide, the person should speak with a doctor immediately.
  • Withdrawal symptoms: Some people who take SSRIs and SNRIs experience some withdrawal symptoms when they stop taking the medication. Withdrawal symptoms can last for 1–2 weeks and include:

Suicide prevention

If you know someone at immediate risk of self-harm, suicide, or hurting another person:

  • Ask the tough question: “Are you considering suicide?”
  • Listen to the person without judgment.
  • Call 911 or the local emergency number, or text TALK to 741741 to communicate with a trained crisis counselor.
  • Stay with the person until professional help arrives.
  • Try to remove any weapons, medications, or other potentially harmful objects if it’s safe to do so.

If you or someone you know is having thoughts of suicide, a prevention hotline can help. The 988 Suicide and Crisis Lifeline is available 24 hours a day at 988. During a crisis, people who are hard of hearing can use their preferred relay service or dial 711 then 988.

Find more links and local resources.

Antidepressants tend to be effective. However, everyone responds to medication differently.

According to the Institute for Quality and Efficiency in Health Care, 40–60% of people who took an SSRI or SNRI for depression noticed some symptom relief within 6–8 weeks.

The research notes that the more severe the depression, the greater the benefits of antidepressants may be.

People may wish to try the following:

Therapy

People with depression may wish to undergo therapy. Types of therapy that can help treat depression include:

St. John’s wort

Hypericum, made from the herb St. John’s wort, might help relieve depression in some people. It is available over the counter as a supplement.

However, there are some possible risks associated with taking hypericum:

  • If combined with certain antidepressants, it can lead to a potentially life threatening increase in serotonin.
  • It can worsen symptoms of bipolar disorder and schizophrenia.
  • It might reduce the effectiveness of some prescription medications, including antidepressants, birth control pills, some heart medications, warfarin, and some therapies for HIV and cancer.

If a person plans to take St. John’s wort, they should first talk with a doctor or pharmacist.

Light box

People who experience seasonal affective disorder may benefit from light therapy.

It involves sitting in front of a light box first thing in the morning for 30–45 minutes.

Diet and exercise

The Centers for Disease Control and Prevention (CDC) notes that regular physical activity can reduce a person’s risk of depression. People may wish to try three exercise sessions per week for 12–24 weeks.

People may also benefit from eating a balanced, nutritious diet full of fresh and whole foods. They may wish to avoid or limit refined and processed foods.

While different antidepressants work in different ways, they all affect neurotransmitters. Neurotransmitters are chemicals brain cells use to communicate with each other.

Antidepressants work in the following ways:

  • SSRIs: These prevent serotonin from returning to where it came from, also known as preventing serotonin reuptake. This encourages serotonin to bind to its receptor to transmit a signal in the brain.
  • SNRIs: These work the same as SSRIs, except they work on both serotonin and norepinephrine.
  • TCAs: These work the same as SNRIs, except they are less effective at blocking norepinephrine reuptake than serotonin reuptake.
  • MAOIs: These target the brain enzyme monoamine oxidase, which helps break down neurotransmitters such as serotonin. This can lead to more stabilized moods and less anxiety.

According to the NHS, people may begin to feel the benefits of an antidepressant after 1–2 weeks if they have not missed a dose.

Some people may stop taking their antidepressant because they believe the medication is not working. However, it is important to keep taking the medication exactly as a doctor prescribes.

If a person has not noticed any benefit after 4 weeks, they should speak with a doctor.

Below are some commonly asked questions about antidepressants.

Which antidepressant is right for me?

There are many types of antidepressants. They all work differently and have different benefits, risks, and side effects.

A person can speak with a doctor about their individual circumstances. The doctor can help them find the best treatment option for them.

Are antidepressants safe during pregnancy?

The CDC notes there is a link between taking SSRIs during pregnancy and congenital abnormalities. However, this risk is very low.

For some people, the risks associated with stopping the medication are higher than those associated with continuing to take it.

If a person is pregnant and wishes to continue or begin taking antidepressants, they should speak with a doctor.

Tiny amounts of some antidepressants can enter breast milk. However, the CDC states most antidepressants will have no effect on milk supply or the child’s well-being.

How long should I stay on antidepressants?

According to the NHS, doctors typically suggest a person takes antidepressants for at least 6 months.

People should take their antidepressants exactly as their doctor has prescribed.

Antidepressants can help relieve symptoms of conditions such as depression and anxiety disorders. They work by increasing neurotransmitters in the brain.

Examples of antidepressants include SSRIs, SNRIs, TCAs, and NaSSAs. MAOIs may also be an option, though doctors prescribe these less often due to the risk of adverse side effects.

It can take several weeks for antidepressants to start working. People may experience side effects.

Alternatives to antidepressants include therapy, diet and exercise, and St. John’s wort. However, depression is a serious condition that may need professional treatment. Anyone who experiences the symptoms of depression should speak with a doctor.