Questions? Call us at 800-810-7790
Oct 25, 2022

Mental Health


What to Expect During the First Few Weeks on Antidepressants

Antidepressants are medications prescribed to treat a number of mental health conditions. The main mental health conditions that antidepressants are prescribed to treat include anxiety disorders (including generalized anxiety disorder and obsessive compulsive disorder) and mood disorders (including major depressive disorder and post-partum depression).

In general, these medications work to increase the “good” chemicals in the brain. The main three of these chemicals responsible for increasing mental health stability, include:

  • Serotonin—This is a “happy” chemical, and works to improve your mood, sleep, and appetite.
  • Norepinephrine—This is a “fight or flight” chemical, and increases your energy, alertness, and attention
  • Dopamine—This is a “reward” chemical, and works to make you feel happy, relaxed, and increase feelings of pleasure.

When treating mental health conditions, it’s typical to start treatment with self-directed improvements or talk therapy. However, if the mental health condition is severe and/or non-medication options are not working, your healthcare provider (HCP) will likely start you on an antidepressant. These medications are extremely effective, though they work slightly differently for each person. Because of this, many people have to try a few different medications before they find the one that works best for them.

Most antidepressants work by decreasing the reuptake of serotonin and/or norepinephrine and/or dopamine. In a normal situation, these chemicals would be released by one cell in the brain and go signal another cell in the brain. “Reuptake” of these chemicals removes the chemical from the space between these two nerve cells and therefore stops them from having any more activity. Decreasing reuptake gives the chemicals more time to act, which then has a positive impact on mood and anxiety disorders.


Different Antidepressant Types

There are a number of different types of antidepressants, each of which work slightly differently.

  • Selective Serotonin Reuptake Inhibitors (SSRIs)
  • Serotonin Norepinephrine Reuptake Inhibitors (SNRIs)
    • SNRIs stop the reuptake of serotonin and norepinephrine. This improves your mood and also increases energy, alertness, and attention.
    • The most common SNRIs include desvenlafaxine, venlafaxine, and duloxetine.
  • Tricyclic Antidepressants (TCAs)
    • TCAs cause a decreased reuptake of norepinephrine and serotonin. They differ from SNRIs, as TCAs work more on norepinephrine than serotonin.
    • Common TCAs are amitriptyline and nortriptyline.
  • Atypical Antidepressants (ATAs)
    • ATAs are a class of antidepressants that don’t fit into any other class.
    • The most common atypical antidepressant is bupropion.
      Bupropion stops the reuptake of dopamine, serotonin, and norepinephrine. This regulates out the chemicals that are potentially imbalanced and therefore reduces symptoms of depression.
  • Monoamine oxidase inhibitors (MAOIs)
    • MAOIs stop the enzyme that is responsible for breaking down serotonin, norepinephrine, and dopamine. An increased amount of these chemicals works to decrease negative symptoms of depression.
    • An example of an MAOI is phenelzine.

SSRIs are the most commonly prescribed antidepressant because they are effective for most people and tend to have the least problematic side effects. However, if the side effects are too severe or the medications are not working for you, your HCP will likely prescribe you an SNRI. Once both SSRIs and SNRIs have failed, ATAs and TCAs are the next option. In general, MAOIs are the least commonly prescribed antidepressant. This is largely due to the large number of interactions they have with other medications, as well as the more severe side effects.

Side Effects of Antidepressants

Each kind of antidepressant has a slightly different side effect profile. Even within each class of antidepressants the side effects vary, especially person-to-person. In general, these are the typical side effects experienced for the most common antidepressants:

  • Selective Serotonin Reuptake Inhibitors (SSRIs)
    • Headache
    • Nausea
    • Difficulty sleeping
    • Tiredness
    • Sexual dysfunction
  • Serotonin Norepinephrine Reuptake Inhibitors (SNRIs)
    • Headache
    • Dizziness
    • Difficulty sleeping
    • Weakness and tiredness
    • Increased sweating
  • Tricyclic Antidepressants (TCAs)
    • Dry mouth
    • Dizziness
    • Memory problems
    • Increased heartrate
    • Sexual dysfunction
  • Atypical Antidepressants (ATAs)
    • Headaches
    • Difficulty sleeping
    • Irritability
    • Weight loss
    • Nausea/vomiting
  • Monoamine oxidase inhibitors (MAOIs)
    • *Potential for serotonin syndrome
    • Weight gain
    • Dizziness
    • Dry mouth
    • Sexual dysfunction
*serotonin syndrome is a condition that can occur when too much serotonin accumulates in your body. This is a very serious condition that can lead to seizures and even potentially death. When you take MAOIs alongside any other medication that increases serotonin, there is a high risk of this occurring.

Another, relatively uncommon, but very serious, side effect experienced by some people when they first start taking an antidepressant is a worsened mood and increased thoughts of hurting yourself and/or suicide. This is considered a medical emergency, and if you experience any of these effects when you begin taking a new antidepressant, seek medical attention immediately. This is also important if you have been on an antidepressant long-term or are not on any medication at all.

The First Few Weeks on Antidepressants

It is extremely important to note that most side effects will improve or resolve entirely within the first 2–4 weeks on each antidepressant. It also usually takes about 1–4 weeks (depending on the medication) for antidepressants to start having an effect on your mood. Because of this, many people stop taking their medication in those first few weeks as they think the medication isn’t working and the side effects are too severe. It’s extremely important to wait those 2–4 weeks to actually assess whether or not the medication is working for you and if the side effects are interfering with the benefits of taking the medication.

Some side effects, however, will not go away and will remain as you stay on the medication. This won’t be obvious until you have been taking the medication for an extended period of time. Some side effects are more likely to be short term, such as drowsiness and nausea, while others, such as weight gain and sexual dysfunction, are more often experienced longer-term. Because of this, it’s important to remain aware of any changes to your body that occur as you adjust to your new medication. Some side effects, even if they remain long-term, are worth the benefit you get from an antidepressant. Weighing the pros and cons of a new medication is always something that must be done between you and your HCP.

After the First Few Weeks

If you have been taking your antidepressants as prescribed for over 2–4 weeks (or for the duration your HCP has recommended based on your health and the specific medication), and you are still experiencing side effects or not experiencing an improvement in your mood, then you should speak with your HCP about possibly switching to another antidepressant.

Just because one antidepressant did not work for you does NOT mean that antidepressants in general don’t work for you. There are over 30 common antidepressants, and if one does not work for you, there is a high likelihood that another one will!

  1. Kelly K, Posternak M, Alpert JE. Toward achieving optimal response: understanding and managing antidepressant side effects. Dialogues Clin Neurosci. 2008;10(4):409-18. doi: 10.31887/DCNS.2008.10.4/kkelly. PMID: 19170398; PMCID: PMC3181894.
  2. Sheffler ZM, Abdijadid S. Antidepressants. [Updated 2022 Jul 6]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from:
  3. [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. Depression: How effective are antidepressants? [Updated 2020 Jun 18]. Available from:
  4. Managing the Side Effects of Depression Treatment. (2022). Retrieved 5 August 2022, from
  5. Antidepressant Side Effects: Types, Comparison Chart, and Suicide Risk. (2022). Retrieved 5 August 2022, from

Related posts

What Depression Is

Medication Treatment for General Anxiety Disorder (GAD)

Different Types of Depression