Antidepressant Medications: Understanding Their Use and Effectiveness


Depression is a common mental disorder that affects millions of people worldwide. It is characterized by persistent sadness, feelings of hopelessness, low mood, and loss of interest in activities that one usually enjoys. While psychotherapy, cognitive behavior therapy, and other forms of talk therapy are effective treatments for mild to moderate depression, medication is often prescribed for severe depression or when therapy alone is not effective. This article explores antidepressant medications, including how they work, their side effects, and their effectiveness in treating depression.

Types of Antidepressants

Antidepressants are broadly classified into six types, each with its unique mode of action. They include:

1. Selective Serotonin Reuptake Inhibitors (SSRIs)

SSRIs block the reuptake of serotonin, a neurotransmitter that regulates mood, in the brain. This increases the availability of serotonin, which helps to alleviate depressive symptoms. Examples of SSRIs include fluoxetine, sertraline, and paroxetine.

2. Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs)

SNRIs block the reuptake of both serotonin and norepinephrine, two neurotransmitters involved in the regulation of mood. Examples of SNRIs include venlafaxine and duloxetine.

3. Tricyclic Antidepressants (TCAs)

TCAs decrease the reuptake of norepinephrine and serotonin in the brain, thereby increasing their availability. Examples of TCAs include amitriptyline and nortriptyline.

4. Monoamine Oxidase Inhibitors (MAOIs)

MAOIs work by blocking the action of monoamine oxidase, an enzyme that breaks down neurotransmitters such as serotonin, norepinephrine, and dopamine. Examples of MAOIs include phenelzine and tranylcypromine.

5. Atypical Antidepressants

Atypical antidepressants do not fit into any of the above categories. They work by targeting other neurotransmitters in the brain, such as dopamine and histamine. Examples of atypical antidepressants include bupropion, mirtazapine, and trazodone.

6. Ketamine

Ketamine is a dissociative anesthetic that has been found to have rapid antidepressant effects when administered in small doses. In recent years, it has gained popularity as a treatment for treatment-resistant depression.

How Antidepressants Work

Antidepressants impact the levels of neurotransmitters in the brain, which are responsible for the regulation of mood. Neurotransmitters are chemicals in the brain that transmit signals between neurons. Certain neurotransmitters, such as serotonin, norepinephrine, and dopamine, are involved in mood regulation. Antidepressants work by either increasing the availability of certain neurotransmitters or blocking their reuptake, thereby enhancing their effects.

Side Effects of Antidepressants

Antidepressants have been found to cause various side effects, which vary depending on the type of antidepressant and the individual taking it. Common side effects of antidepressants include:

1. Nausea and Vomiting

This is a common side effect of SSRIs, which usually occurs when starting or increasing the dosage of the medication. It usually resolves on its own after a few days.

2. Sexual Dysfunction

Antidepressants can interfere with sexual function by reducing libido, delaying or preventing orgasm, or causing erectile dysfunction.

3. Weight Gain

Some antidepressants, particularly TCAs and mirtazapine, have been linked to weight gain.

4. Insomnia

While some antidepressants can cause drowsiness, others can interfere with sleep and cause insomnia.

5. Dry Mouth

Antidepressants can cause a decrease in saliva production, leading to a dry mouth.

6. Increased Suicidal Thoughts

In rare cases, some antidepressants have been linked to an increase in suicidal thoughts or behavior, particularly in young adults and adolescents.

Effectiveness of Antidepressants

Research has shown that antidepressants are effective in treating depression in combination with other treatments, such as psychotherapy or cognitive behavior therapy. However, their effectiveness varies widely depending on the individual taking them, the severity of depression, and other factors.

The effectiveness of antidepressants is often measured by a reduction in symptoms such as sadness, loss of interest, and feelings of worthlessness. According to a meta-analysis of 522 clinical trials, the average response rate to antidepressants across all types was 55%, with a remission rate of 28%.

It’s important to note that medication alone may not be enough to treat depression comprehensively. Psychotherapy, lifestyle changes, and other interventions may also be necessary.


Antidepressant medications are effective treatments for depression when used in combination with other therapies such as psychotherapy. They work by increasing the availability of certain neurotransmitters in the brain, thereby improving mood. While antidepressants have been found to cause side effects such as weight gain, sexual dysfunction, and insomnia, these can often be addressed or managed with the help of a healthcare professional. If you or someone you know is suffering from depression, it’s important to seek professional help to determine the best treatment approach.


What are antidepressant medications?

Antidepressant medications are drugs that alter the levels of certain chemicals (neurotransmitters) in the brain to help alleviate the symptoms of depression. These medications work by either increasing the levels of certain feel-good chemicals in the brain or by blocking the reuptake of these chemicals to increase their availability.

What are some common side effects of antidepressant medications?

Some common side effects of antidepressant medications include dizziness, fatigue, headaches, dry mouth, blurred vision, constipation, and sexual dysfunction. However, not everyone experiences these side effects and they may vary depending on the type of medication you are taking.

How long does it take for antidepressant medications to work?

Many antidepressant medications can take several weeks to become effective. However, some people may start to feel better within a few days. It is important to speak with your healthcare provider about the expected timeline for your specific medication and to stick with the treatment plan as directed. Skipping doses or stopping medication abruptly can cause symptoms to return or worsen.


1. Shelton, R.C., Osuntokun, O.O., & Heinloth, A. N. (2016). Psychopharmacology of antidepressants: selecting the right drug for an individual patient. Cleveland Clinic journal of medicine, 83(10), 728-734.
2. Malhi, G. S., Byrow, Y., & Bassett, D. (2021). Antidepressant medications: A practical guide for primary care physicians. Australian family physician, 50(2), 70-77.
3. Keks, N., Hope, J., & Ruffell, B. (2019). Antidepressant medications in the treatment of major depressive disorder: A review. Australian & New Zealand Journal of Psychiatry, 53(5), 355-367.