Do antidepressants work? How to know if antidepressants can be effective and safe for you
- Antidepressants can be effective at treating moderate, severe, or chronic depression.
- This medication may also be helpful at treating chronic pain and certain anxiety disorders.
- Here's what you need to know about the different types of antidepressants and how to use them safely and effectively.
- This article was medically reviewed by David A. Merrill, MD, PhD, psychiatrist and director of the Pacific Brain Health Center at Pacific Neuroscience Institute at Providence Saint John's Health Center.
Antidepressants are most effective at helping to treat the symptoms of moderate to severe depression.
About one out of 10 people over the age of 12 in the US takes antidepressants. In fact, from 1999 to 2014, antidepressant usage increased by 64%, the American Psychological Association (APA) reports.
There are a few different types of antidepressants, and some work better for certain people. Here's what you should know about the safety and effectiveness of antidepressant medications, and whether they are right for you.
What are antidepressants?
Antidepressant medications are prescribed to treat and relieve the symptoms of moderate to severe depression. They may also be helpful for treating anxiety disorders like panic disorder, obsessive-compulsive disorder (OCD), and chronic pain.
How do antidepressants work?
It's not known precisely how antidepressants work. It's believed that they help balance your brain's neurotransmitters. These are the chemicals that carry signals between your brain's nerve cells, or neurons, and regulate your emotional and physical health.
Specifically, the neurotransmitters serotonin and noradrenaline (also known as norepinephrine) are associated with emotion and mood. Serotonin, which enhances communication between neurons, affects your feelings of happiness and well-being, while noradrenaline affects your energy and alertness.
Some research suggests that people with depression may produce lower levels of these neurotransmitters, or there may be a disturbance in the signals between neurons.
Antidepressants prevent these neurotransmitters from being reabsorbed into the brain's neurons, and as a result, they are better able to transmit messages between neurons.
In turn, a higher level of neurotransmitters may help improve communication between the neurons, which can help regulate your mood and relieve symptoms of depression, anxiety, or chronic pain.
Types of antidepressants
There are three main types or classes of antidepressants:
Selective serotonin reuptake inhibitors (SSRIs)
SSRIs are the most commonly prescribed antidepressants for people with moderate to severe depression. They work by blocking serotonin from being absorbed into neurons. This increases the brain's serotonin level and enhances communication between neurons, leading to improved mood.
Examples include:
- Celexa (citalopram)
- Lexapro (escitalopram)
- Paxil (paroxetine)
- Prozac (fluoxetine)
- Zoloft (sertraline)
Serotonin and noradrenaline reuptake inhibitors (SNRIs)
SNRIs are newer types of antidepressants that treat depression as well as anxiety disorders. They are sometimes prescribed if SSRIs have not been effective. They work by blocking the reabsorption of serotonin and noradrenaline into the brain's neurons.
Examples include:
- Pristiq (desvenlafaxin)
- Fetzima (levomilnacipran)
- Cymbalta (duloxetine)
- Effexor XR (venlafaxine)
Tricyclic antidepressants (TCAs)
TCAs have been on the market the longest — since the 1950s — and may cause more side effects than newer antidepressants. They are usually prescribed only when other antidepressants haven't been effective.
TCAs also work by stopping serotonin and noradrenaline from binding with certain receptors on the neurons. Examples include:
- Anafranil (clomipramine)
- Tofranil (imipramine)
- Elavil (amitriptyline)
- Pamelor (nortriptyline)
- Sinequan (doxepin)
Do antidepressants work?
Research has found that about 40% to 60% of adults who take antidepressants noticed an improvement in their depression symptoms in six to eight weeks. However, the same studies have also found that about 20% to 40% of adults who took a placebo also noticed an improvement in their depression symptoms in the same time period.
This may be because the effectiveness of antidepressants varies among people who take them. Antidepressants are the most effective for people with moderate to severe depression.
Though specific types of antidepressants have been found to be more effective than others. In a 2018 study published in The Lancet, researchers analyzed 21 types of antidepressants prescribed to over 116,000 adults with major depression and found they were all more effective than placebos. Some antidepressants, including Cymbalta and Elavil, were found to be twice as effective than placebos, while others, such as Prozac and Anafranil, were about three times more effective.
It's not known why, but some people respond better to certain antidepressants than to others.
"Even the very best treatments we have don't work for everyone," says Daniel Strunk, PhD, an associate professor of psychology at Ohio State University. "Those considering antidepressant medications should be aware that trying an antidepressant often involves trying more than one drug."
Moreover, some people with depression don't necessarily need antidepressants. For example, Strunk says that cognitive behavioral therapy has been found to be as effective as antidepressant medication, even for people with moderate to severe depressive symptoms.
If you have mild to moderate depressive symptoms, Strunk recommends first considering other treatments such as psychotherapy or an exercise program.
Side effects of antidepressants
"It appears that antidepressant medications can be used safely in many cases, but these drugs come with some risks," Strunk says.
About 63% of people taking antidepressants experience at least one side effect, especially during the first two weeks. SSRIs generally have fewer side effects than other types of antidepressant medication.
TCAs have the most side effects and a greater potential for overdose because they have a narrow therapeutic index, meaning that the prescribed dose is close to the toxic dose.
These are some of the common side effects of the three main types of antidepressants:
SSRIs and SNRIs
- Headache
- Nausea and vomiting
- Diarrhea
- Drowsiness
- Insomnia
- Nervousness
- Dizziness
- Reduced sexual desire
- Increased suicidal thoughts or behavior, especially for young people under the age of 25
TCAs
- Drowsiness
- Constipation
- Blurred vision
- Dry mouth
- Lightheadedness when standing up due to a drop in blood pressure
Because antidepressant medications may increase suicidal thoughts and behavior in people under the age of 25, the FDA requires all of them to have black box warnings, which are the strictest warnings for prescription drugs.
How to use antidepressants safely
Antidepressants are usually taken daily for at least one year. It may take two to three weeks to start experiencing their benefits. And even if you begin feeling better, you should continue to take them as prescribed by your doctor.
Although antidepressants are not addictive, it's important to gradually stop taking them by reducing the dose. Stopping them suddenly could cause antidepressant discontinuation syndrome, with withdrawal-like symptoms such as uneasiness, nausea, and dizziness.
If your doctor prescribes antidepressants, you should work with them to create a treatment plan, and consult them before you adjust your dosage. In addition, to take antidepressants safely, you should be aware of the following:
- Antidepressants may trigger manic episodes in people with bipolar disorder.
- People over the age of 65 may have a higher risk of falls, fractures, and bone loss.
- Although the risks for birth defects are low for most antidepressants, Paxil (paroxetine) and Anafranil (clomipramine) are generally not recommended for women who are pregnant or breast-feeding due to the small possibility of a fetal heart defect.
The bottom line
For many people, antidepressants can be an important part of an effective treatment plan for depression, anxiety disorders, and chronic pain.
The antidepressant that's best for you depends on several factors, including your symptoms and physical health. When deciding which antidepressant to prescribe, your doctor may consider factors such as side effects, your history with specific drugs, and medication cost.
If you're experiencing moderate to severe depression, talk to your doctor about which antidepressant would be most effective for you.