Antidepressant Medications: Definition, Types, Side Effects, Uses, Efficacy, and Alternative Options

They were first developed in the 1950s. Their use has become progressively more common in the last 20 years.

Antidepressants are medications that can help relieve symptoms of depression, social anxiety disorder, anxiety disorders, seasonal affective disorder, dysthymia, or mild chronic depression, as well as other conditions.

Its goal is to correct chemical imbalances of neurotransmitters in the brain that are believed to be responsible for changes in mood and behavior.

According to the Centers for Disease Control and Prevention (CDC), the percentage of 12 and older who use antidepressants in the United States increased from 7.7 percent in 1999-2002 to 12.7 percent in 2011-2014.

About twice as many women use antidepressants as men.


Antidepressants can be divided into five primary types:


These are the most common types of antidepressants.

Serotonin and norepinephrine reuptake inhibitors (SNRIs) treat major depression and mood disorders.

Although less common, these are also used to treat attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), anxiety disorders, menopausal symptoms, fibromyalgia, and chronic neuropathy.

SNRIs increase levels of serotonin and norepinephrine, two neurotransmitters in the brain that play a crucial role in stabilizing mood.

Examples include duloxetine (Cymbalta), venlafaxine (Effexor), and desvenlafaxine (Pristiq).

Selective serotonin reuptake inhibitors (SSRIs)  are the most commonly prescribed antidepressants. They effectively treat depression and have fewer side effects than the other antidepressants.

SSRIs block the reabsorption or absorption of serotonin in the brain.

This makes it easier for brain cells to receive and send messages, resulting in better and more stable moods. They are called “selective” because they seem to affect mainly serotonin and not the other neurotransmitters.

SSRIs and SNRIs can have the following side effects:

  • Hypoglycemia or low blood sugar.
  • Low in sodium levels.
  • Nausea.
  • Eruption.
  • Dry mouth.
  • Constipation or diarrhea
  • Weightloss.
  • Perspiration.
  • Temblor.
  • Sedation.
  • Sexual dysfunction
  • Insomnia.
  • Headache.
  • Dizziness.
  • Anxiety and agitation.
  • Abnormal thoughts

Examples include citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac, Sarafem), fluvoxamine (Luvox), and paroxetine (Paxil), and sertraline (Zoloft).

There have been reports that people using SSRIs and SNRIs, especially those under 18, may experience suicidal thoughts, especially when they start using the medications.

All antidepressants carry a black box warning for this effect, as required by the Food and Drug Administration (FDA).

Tricyclic antidepressants (ATC)

Tricyclic antidepressants (TCAs) are so named because there are three rings in the chemical structure of these drugs. They are used to treat depression, fibromyalgia, and some types of anxiety and can help manage chronic pain. Tricyclics can have the following side effects:

  • Seizures
  • Insomnia.
  • Anxiety.
  • Arrhythmia or irregular heartbeat.
  • Hypertension.
  • Eruption.
  • Nausea and vomiting
  • Abdominal cramps
  • Weightloss.
  • Constipation.
  • Urinary retention.
  • Increased pressure in the eye.
  • Sexual dysfunction

Los ejemplos incluyen: amitriptilina (Elavil), amoxapina-clomipramina (Anafranil), desipramina (Norpramin), doxepina (Sinequan), imipramina (Tofranil), nortriptilina (Pamelor), protriptilina (Vivactil) y trimipramina (Surmontil).

Monoamine oxidase inhibitors (MAOIs)

This type of antidepressant was commonly prescribed before introducing SSRIs and SNRIs. It inhibits the action of monoamine oxidase, a brain enzyme. Monoamine oxidase helps break down neurotransmitters, such as serotonin.

If less serotonin is broken down, there will be more circulating serotonin. In theory, this leads to more stabilized moods and less anxiety.

Doctors now use MAOIs if SSRIs have not worked. MAOIs are generally saved for cases where other antidepressants have not worked because MAOIs interact with various other medications and some foods. Side effects include:

  • Blurry vision.
  • Eruption.
  • Seizures
  • Edema.
  • Weight loss or weight gain.
  • Sexual dysfunction
  • Diarrhea, nausea, and constipation.
  • Anxiety.
  • Insomnia and drowsiness.
  • Headache.
  • Dizziness.
  • Arrhythmia or irregular heartbeat.
  • Fainting or feeling faint when standing up.
  • Hypertension or high blood pressure

Los ejemplos de IMAO incluyen: fenelzina (Nardil), tranilcipromina (Parnate), isocarboxazida (Marplan) y selegilina (EMSAM, Eldepryl).

Noradrenaline and specific serotonergic antidepressants (NASSA)

These are used to treat anxiety disorders, personality disorders, and depression. Possible side effects include:

  • Constipation.
  • Dry mouth.
  • Weight gain.
  • Drowsiness and sedation
  • Blurry vision.
  • Dizziness.

The most severe adverse reactions include seizures, reduced white blood cells, fainting, and allergic reactions.

Examples include Mianserin (Tolvon) and Mirtazapine (Remeron, Avanza, Zispin).

Side effects

Any side effects will likely occur during the first two weeks and gradually disappear. Common effects are nausea and anxiety, but this will depend on the drug used, as mentioned above.

If the side effects are very unpleasant or include thinking about suicide, the doctor should be informed immediately. Additionally, research has linked the following adverse effects to antidepressant use, especially among children and adolescents.

The food cravings are interesting, probably less a side effect of Deanxit than a symptom of your hidden depression. It takes a few weeks to lift the mood, so I would stick it out for six weeks (and try to eat slowly but not too much).

Excessive elevation of mood and activation of behavior

This can include mania or hypomania. It should be noted that antidepressants do not cause bipolar disorder, but they can unmask a condition that has yet to be revealed.

Suicidal thoughts

There have been some reports of an increased risk of having suicidal thoughts when using antidepressants for the first time.

This could be due to drugs or other factors, such as how long it takes the drug to work, or possibly an undiagnosed bipolar disorder that may require a different approach to treatment.

The FDA requires antidepressants to have a black box warning of this possible effect.

Withdrawal symptoms

Unlike some medications, you do not need to keep increasing the dose to get the same effect as antidepressants.

In that sense, they are not addictive. When you stop using an antidepressant, you will not experience the same withdrawal symptoms that occur, for example, when you quit smoking.

However, nearly 1 in 3 people who used SSRIs and SNRIs reported some withdrawal symptoms after stopping treatment.

Symptoms lasted from 2 weeks to 2 months and included:

  • Anxiety.
  • Dizziness.
  • Nightmares or vivid dreams.
  • Sensations are similar to an electric shock in the body.
  • Flu-like symptoms
  • Abdominal pain.

In most cases, the symptoms were mild. Severe cases are rare and are more likely after stopping Seroxat and Effexor.

Doctors should reduce the dose gradually to minimize the risk of unpleasant withdrawal symptoms.


These medications are used not only to treat depression but also for other conditions. The primary or approved uses of antidepressants are to treat:

  • Agitation.
  • Obsessive-compulsive disorders (OCD).
  • Enuresisinfantil o enuresis.
  • Depression and major depressive disorder.
  • Generalized anxiety disorder.
  • Bipolar disorder.
  • Post-traumatic stress disorder (PTSD).
  • Social anxiety disorder.

Sometimes a drug is used “off-label.” This means that the FDA does not approve the use, but a doctor may decide that it should be used as it can be an effective treatment. Uses for antidepressants that are not listed on the label include:

  • Insomnia.
  • Pain.
  • Migraine.

Studies suggest that 29 percent of antidepressant use is for an off-label purpose.


It can take several weeks for a person to notice the effects of an antidepressant. Many people stop using them because they think the drugs do not work. Reasons why people may not see an improvement include:

  • The drug is not suitable for the individual.
  • A lack of monitoring by the healthcare provider.
  • A need for additional therapies, such as cognitive-behavioral therapy (CBT).
  • Forgetting to take medicine at the right time.

Staying in contact with the doctor and going to follow-up appointments helps improve the chances that the medicine will work. It may be that the dose needs to be changed or that another medicine is more suitable.

It is essential to take the antidepressant as directed, or it will not be effective.

Most people will not feel any benefit during the first week or two. The total effect will not be present until after 1 or 2 months. Perseverance is vital.

How long does the treatment last?

According to the Royal College of Psychiatry in the UK, 5 to 6 people in 10 will experience significant improvement after three months.

People using medications should continue for at least six months after they feel better. Those who stop before eight months of use may see a return of symptoms.

Those who have had one or more recurrences should continue treatment for at least 24 months.

Those who regularly experience relapses of depression may need to use the drug for several years.

However, a review of the literature published in 2011 found that long-term use of antidepressants can worsen symptoms in some people, as it can lead to biochemical changes in the body.

Antidepressants in pregnancy and lactation


In the United States, 8 percent of women use antidepressant drugs during pregnancy.

SSRI use during pregnancy has been linked to an increased risk of pregnancy loss, preterm delivery, low birth weight, and congenital disabilities.

Possible problems during delivery include excessive bleeding in the mother. After birth, the newborn may experience lung problems known as persistent pulmonary hypertension.

A study of 69,448 pregnancies revealed that using SNRIs or TCAs during pregnancy can increase the risk of pregnancy-induced hypertension or high blood pressure, known as pre-eclampsia. However, it is not clear if this is due to drugs or depression.

Findings published in JAMA in 2006 suggest that nearly 1 in 3 babies whose mothers used antidepressants during pregnancy experienced neonatal withdrawal syndrome. Withdrawal symptoms include disturbed sleep, tremors, and high-pitched crying. In some cases, the symptoms were severe.

A laboratory study found that rodents exposed to citalopram – an SSRI antidepressant – just before and after birth showed significant brain abnormalities and behaviors.

However, for some women, the risk of continuing the medication is less than the risk of stopping, for example, if her depression could trigger an action that could harm her or her unborn baby.

The doctor and patient should thoroughly weigh the benefits and potential harms of stopping antidepressants at this time. Other therapies should be considered, such as cognitive CBT, meditation, or yoga.


Small amounts of some antidepressants enter breast milk, for example, sertraline and nortriptyline. Within a few weeks after birth, babies can break down the medication’s active ingredients in the liver and kidneys just as effectively as adults.

The decision to use antidepressants at this time will involve several factors:

  • Is the child healthy?
  • Were they born prematurely?
  • Will the mother’s condition deteriorate?

How many will active ingredients enter breast milk, which depends on the type of medicine?

A study published in  The Journal of Clinical Endocrinology and Metabolism (The Journal of Clinical Endocrinology and Metabolism ) found that for women who use antidepressants during pregnancy, breastfeeding may take longer.

The researchers explain that the mammary glands are regulated by serotonin. Hence, their ability to produce milk at the right time is related to the production and regulation of this hormone.

Alternative options

CBT and other types of counseling and therapy can also help with depression.

Grass of San Juan

Hypericum, made from St. John’s wort, has been shown to help some people with depression. It is available over the counter as a supplement. However, it should only be taken after speaking with a doctor, as there are some possible risks:

  • In combination with certain antidepressants, St. John’s wort can lead to a life-threatening spike in serotonin.
  • It can make the symptoms of bipolar disorder and schizophrenia worse. A person who has or may have depression related to the bipolar disorder should not use St. John’s wort.
  • Some prescription medications can be less effective, including birth control pills, heart medications, warfarin, and some HIV and cancer therapies.

It is important to tell your doctor or pharmacist if you plan to take St. John’s wort. Some evidence supports the use of St. John’s wort to treat depression, but some studies have found that it is no more effective than a placebo.


People experiencing seasonal affective disorder (SAD) or “winter blues” may benefit from light therapy. This involves sitting in front of a lightbox first thing in the morning for 20 to 60 minutes.

Vitamin D supplements may or may not help treat SAD. The evidence is not conclusive.

Diet and exercise

Some studies have shown that a healthy, well-balanced diet, enough exercise, and contact with family and friends can reduce the risk of depression and recurrences.

Depression is a severe illness that may need medical treatment. Anyone experiencing the symptoms of depression should seek medical advice.