Negative Side Effects of Antidepressants

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What is the most important information I should know about antidepressants?

Tell your doctor if you are taking medications or supplements that affect serotonin levels and seek medical help if you:

  • experience suicidal thoughts or behaviors while taking antidepressants; or
  • have symptoms of an allergic reaction; or
  • experience mania, seizures, or other serious symptoms.

All medications, including antidepressants, can produce unwanted negative effects that we refer to as side effects. Some of these negative effects may be quite mild, while others may be more severe. In addition, they may go away or become less severe in time.

If you experience problems with side effects, you should mention these to your doctor as they may be able to either give you strategies for coping with the side effects or prescribe a different antidepressant for you that has fewer or more tolerable side effects.

Common Side Effects

Some of the more common negative effects that people may experience with antidepressants include:

Your doctor can offer you appropriate coping strategies that can help. They may also change your dose or transition you to a different medication you can better tolerate. Side effects may decline after a few weeks once your body adapts to the medications, but some people experience some side effects for longer.

Tactics that can help people cope with side effects include taking medication with food, increasing fluid intake, getting enough rest, and engaging in regular exercise.

Serious Side Effects

Though they are rare, some side effects of antidepressants are serious, so you should be aware of them. Among these are:

Serotonin Syndrome

Serotonin syndrome occurs when a neurotransmitter, or a chemical messenger, in the brain called serotonin reaches dangerously high levels. Symptoms of serotonin syndrome include confusion, agitation, muscle twitching, sweating, shivering, and diarrhea. In severe cases, people may have symptoms such as very high fever, seizures, irregular heartbeat, and unconsciousness.

This side effect is linked to the use of antidepressants, including:

Serotonin syndrome is generally triggered when an SSRI or SNRI medication is used in combination with a second medication that also affects serotonin levels, such as another antidepressant.

If a person begins to exhibit any of the above symptoms, medical care should be sought immediately as this condition can be life-threatening.


Hyponatremia is a condition in which sodium, or salt, levels in the blood fall to abnormally low levels. When this happens, dangerous amounts of fluid can build up inside the body's cells.

This side effect can occur with SSRIs because these drugs can potentially impact the effects of a hormone involved in regulating sodium and fluid levels within the body. Older people may be especially prone to hyponatremia.

Mild cases of hyponatremia can cause symptoms such as:

  • Confusion
  • Feeling ill
  • Headache
  • Loss of appetite
  • Muscle pain

In more severe cases, people may also experience such symptoms as listlessness and fatigue, disorientation, agitation, psychosis, and seizures. In addition, hyponatremia has the potential to lead to coma or death.

People who experience even mild symptoms of hyponatremia should seek immediate medical care.

Suicidal Thoughts

You should be aware that when you're first starting an antidepressant, you may experience a temporary worsening of your depression and potentially even increased thoughts of suicide. Studies indicate that this may be especially true for people younger than age 25.

If you, or someone you are caring for, experience any worsening of depression, increased thoughts of suicide or death, or unusual changes in behavior in the first weeks after starting a new antidepressant, it is important to get medical assistance immediately.

If you are having suicidal thoughts, contact the National Suicide Prevention Lifeline at 988 for support and assistance from a trained counselor. If you or a loved one are in immediate danger, call 911.

For more mental health resources, see our National Helpline Database.

Allergic Reactions

Allergic reactions can occur with antidepressants, either because a person is allergic to the active ingredient of the medication or because they are allergic to the dyes, fillers, or other inactive ingredients present in the pill or capsule.

Symptoms of an allergic reaction can include swelling, itchy rash, hives, blisters, or difficulty breathing. A severe allergic reaction can become life-threatening if it blocks a person's ability to breathe. Medical help should be sought for an allergic reaction, especially if there is swelling in the face or breathing difficulty.


In people with bipolar disorder, antidepressants can potentially trigger an episode of mania, especially if used without a mood-stabilizing drug. Symptoms of mania include increased energy and activity, problems with sleeping, racing thoughts, impulsive behavior, grandiose thinking, extreme elevation of mood, irritability, and pressured speech.

While mania is not necessarily life-threatening, it requires medical assistance to treat.


Certain antidepressants can increase a person's risk of having a seizure. In some cases, the seizures may happen in a person who has never had one before. Most antidepressants do not increase seizure risk, although Wellbutrin (bupropion) is the antidepressant that is most likely to trigger one.

Certain older antidepressants called tricyclics can also increase a person's seizure risk. Generally, the newer antidepressants are less likely to trigger seizures.

Seizures involve such symptoms as uncontrollable jerking movements of the arms and legs, staring spells, confusion, abnormal sensations, and loss of consciousness. All seizures should be reported to a doctor. If it is the first time a person has had a seizure, emergency services should be called.

When to Call 911

  • A seizure lasts more than five minutes
  • The person does not wake up
  • Another seizure begins immediately afterward
  • The person is pregnant, injured, or has diabetes
  • The seizure occurs in water
  • There is anything unusual about the seizure compared to others that the person has had before

Consult Your Doctor

Keep in mind, however, that it is never a good idea to stop taking your antidepressant without first discussing it with your doctor. An unpleasant set of symptoms known as discontinuation syndrome may occur if you stop taking your medication too abruptly.

Symptoms of discontinuation syndrome include:

  • Agitation
  • Anxiety
  • Blurred vision
  • Electric shock sensations
  • Fatigue
  • Hallucinations
  • Insomnia
  • Irritability
  • Muscle pain
  • Sweating
  • Tingling
  • Upset stomach
  • Vivid dreams

It's always best to taper off of your antidepressant very slowly with your doctor's guidance. This gives your brain time to get used to the changes, and you will notice fewer effects if you stick with your doctor's plan.

10 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Nancy Schimelpfening
Nancy Schimelpfening, MS is the administrator for the non-profit depression support group Depression Sanctuary. Nancy has a lifetime of experience with depression, experiencing firsthand how devastating this illness can be.