Antidepressants are a category of medications used to treat depression and other mental health illnesses, such as anxiety disorders and chronic pain, among many others.

There are several different types of antidepressants, each affecting brain chemistry in different ways.

This is a post concisely describing them, but I will write a more detailed one describing each one of them extensively in the future.

Take note that I am an occupational therapist and not a doctor. Drugs are not my area of expertise. Therefore, I can’t give you any advice regarding which antidepressant you should take, or whether you should take any at all.

This article simply serves to educate the audience to help make a better-informed decision based on facts, science, and statistics. ALWAYS consult with your primary care physician before taking antidepressants since they can guide you through this process and give you valuable information!

Here are the main categories:

1. Selective serotonin reuptake inhibitors (SSRIs)

• • How they work: SSRIs increase the levels of serotonin in the brain by blocking its reabsorption (reuptake).
  • Examples: Fluoxetine (Prozac), Sertraline (Zoloft), Escitalopram (Lexapro).

2. Serotonin-norepinephrine reuptake inhibitors (SNRIs)

• • How they work: Boost the levels of both serotonin and norepinephrine by preventing their resorption.
  • Examples: Venlafaxine (Effexor), Duloxetine (Cymbalta).

3. Tricyclic antidepressants (TCAs)

• • How they work: They block the reuptake of the neurotransmitters serotonin and norepinephrine. Unfortunately, they are older and often have more side effects.
  • Examples: Amitriptyline, Nortriptyline (Pamelor).

4. Monoamine oxidase inhibitors (MAOIs)

• • How they work: MAOIs work by inhibiting the enzyme monoamine oxidase, which breaks down serotonin, norepinephrine, and dopamine.
  • Examples: Phenelzine (Nardil), Tranylcypromine (Parnate).
  • Note: MAOIs can have serious interactions with certain foods and medications.

5. Atypical antidepressants

• • How they work: These don’t fit into the other categories and have unique mechanisms of action.
  • Examples: Bupropion (Wellbutrin), Mirtazapine (Remeron), Trazodone.

There are a few additional types of antidepressants that I purposely didn’t include in the initial list.

That’s because these are newer or less commonly used medications, but that does in no way mean they’re any less viable for treating psychological issues. Although, as always, there can be some risks.

These novel drugs are:

6. Serotonin modulators

• • How they work: Serotonin modulators regulate serotonin activity by acting on multiple serotonin receptors in different ways. They can enhance serotonin activity in some areas while suppressing it in others, depending on what’s needed to treat the issue.
  • Examples:
    • Vilazodone (Viibryd): Works as a selective serotonin reuptake inhibitor (like SSRIs) but also acts as a partial agonist of serotonin receptors.
    • Vortioxetine (Trintellix): Influences multiple serotonin receptors and reuptake, affecting the serotonin system more broadly than SSRIs.

7. Norepinephrine-dopamine reuptake Inhibitors (NDRIs)

• • How they work: These obstruct the reabsorption of both norepinephrine and dopamine, rather than serotonin.
  • Example: Bupropion (Wellbutrin): Often used to treat depression and as an aid to stop smoking. It’s unique because it typically doesn’t cause sexual side effects or weight gain like many other antidepressants.

8. Tetracyclic antidepressants

• • How they work: These drugs work similarly to tricyclic antidepressants but have a different chemical structure. They also impact the norepinephrine and serotonin levels and regularly act as antagonists at certain receptors.
  • Example: Maprotiline increases norepinephrine levels in the brain.

9. NMDA receptor antagonists (Ketamine-like antidepressants)

• • How they work: NMDA receptor antagonists act on the glutamate system by blocking the NMDA receptors. They are usually used for treatment-resistant depression.
  • Examples:
    • Esketamine (Spravato): A nasal spray version of ketamine, approved for treatment-resistant depression.
    • Ketamine: Typically used off-label for depression in clinical settings.
      It can have rapid, positive short-term effects on depressive symptoms.

10. 5-HT2 receptor antagonists

• • How they work: They block serotonin (5-HT2) receptors, which can help alleviate depression and anxiety.
  • Example: Trazodone is frequently used for its sedating effects as well as for depression.

11. Agomelatine

• • How it works: This drug acts as an agonist at melatonin receptors and an antagonist at serotonin receptors.
    It works by regulating the circadian rhythm and improving sleep quality, which helps to stabilize mood.
  • Example: Agomelatine (Valdoxan): Mainly employed in Europe and other regions outside the U.S.

These newer or atypical antidepressants target different neurotransmitter systems and are often prescribed when traditional SSRIs or SNRIs aren’t effective or well-tolerated.

How long do antidepressants take to work?

It usually takes several weeks (often 4–6 weeks) before antidepressants begin to show their full effects.

It’s common for doctors to start with a low dose and gradually increase it since it takes some time before they show their effect and because they want to keep the efficacious dose as low as possible.

And it’s common for doctors to start with a low dose and gradually increase it.

Risks

Antidepressants are generally safe, but they can pose some health risks.

In some cases, especially for younger individuals, antidepressants may increase the risk of suicidal thoughts during the initial stages of treatment.

Antidepressive medications are usually prescribed as part of a broader treatment plan that typically includes therapy, lifestyle changes, and support systems.

ALWAYS consult your primary care physician before starting to take antidepressants. They know you best and can recommend (and prescribe) the medication that’s best suited to your symptoms and issues.