All About Antidepressants

By Lida Turner, MD

It’s common for people to have questions or concerns about medications for mental illnesses, or even to mistrust them. But medications are a valuable form of treatment for many people. The World Health Organization names depression as the leading cause of disability worldwide, and antidepressants make up a large portion of treatment for not only depression, but anxiety as well. Given that, it’s worth taking the time to understand them.

Antidepressants have been around since the mid-1950s, though over the decades they have become safer and more tolerable, with fewer side effects. There are multiple classes, each with a slightly different way of acting on brain chemical (neurotransmitter) receptors, though the main brain chemical they all seem to work on is serotonin. The classes have their own pros and cons, some of which differ by individual. Sometimes even a negative side effect can be used to help a patient.

What About The Side Effects?

Side effects are often an enormous concern to people, especially when they first start talking about medications. Across all classes, side effects generally occur within the first few weeks of treatment and subside thereafter. Frustratingly, the benefit of these medications can take 4-6 weeks, meaning the side effects often precede any feeling of improvement.

Side effects like dry mouth, stomach upset, and headaches are common across the classes. Sexual side effects are sometimes seen in the different classes, but to varying degrees. This includes things like low libido, anorgasmia (difficulty or not achieving orgasm despite proper stimulation) and erectile dysfunction. These side effects are not permanent and can often be alleviated by lowering the dose of medication; it’s important to be open and discuss this with your prescriber as they won’t know unless you say something.

The challenge for both prescribers and patients is that not everyone experiences the side effects the same way, and some not at all. Personal chemistry is a big factor, and as of yet there are no substantiated ways of determining which medications will be most effective and tolerable for any given patient. We’ll get into the common side effects of specific classes below.

When Are Antidepressants Used?

Medications are generally recommended when someone is diagnosed with depression, especially when symptoms are severe and include thoughts of suicide. Multiple studies have shown the combination of medication and therapy is better than either alone in the treatment of depression. For some, medication is what allows them to start therapy to begin with. With low energy, low interest, and difficulty with concentration, symptoms of depression can make it almost impossible to engage in therapy. Medication can increase energy, improve interest and untangle thoughts, helping patients not only schedule therapy, but engage in session and continue with recommendations after.

Many myths exist about antidepressants, and like the mental health culture in general, they can be heavily stigmatized. Antidepressants do not change your personality or change the situation around you. We repeat: antidepressants do not change your personality or the situation around you. Medications also may not be needed for very long. For less severe depression, 8-12 months at baseline may be all that’s needed. For those who have had 3 or more lifetime episodes of depression, or very, very severe depression, staying on medication long-term is generally recommended.

The Classes of Antidepressants

Tricyclic Antidepressants (TCAs)

The oldest class of antidepressant, dating back to the 1950s. TCAs are still the best choice for some patients.


  • Helpful with sleep
  • Often used with pain issues, migraines

  • Can be too sedating
  • Potential weight gain
  • Toxic in overdose (though doses prescribed now are much lower than they used to be, thus this risk is less)

Monoamine Oxidase Inhibitors (MAOIs)

Another classic, most popular between the 1950s and 1970s. Recent innovations have reinvigorated their use for some patients.


  • Particularly helpful in “atypical” depression (specific symptoms are slightly different than the textbook depression)
  • Available in patch form

  • Interact negatively with many medications (including common cold medication) as well as anything containing tyramine (aged cheeses, wine, meats among other things), so lifestyle changes are needed to take these medications.

Selective Serotonin Reuptake Inhibitors (SSRIs)

SSRIs came out in the 1980s with the advent of Prozac (fluoxetine), and are now the most commonly-used antidepressants.


  • Fewer side effects than the above two classes, and generally well tolerated
  • First-line treatment for anxiety disorders (including generalized anxiety, panic, social anxiety, and Obsessive Compulsive Disorder) as well as PTSD
  • Well-researched for safety

  • Common side effects like dry mouth, stomach upset, headaches, weight gain or loss, and sexual side effects.

Serotonin Norepinephrine Reuptake Inhibitors (SNRIs)

This class is a little newer than the SSRI class. Medications in this class include Effexor (venlafaxine) and Cymbalta (duloxetine).


  • Can be helpful for concurrent pain and migraine issues.

  • May increase blood pressure by a few points, which is limiting for some.

Atypical or “Novel” Antidepressants

These medications don’t fit well into the existing classes, but they also offer unique benefits.
Wellbutrin (bupropion) is a dopamine-norepinephrine reuptake inhibitor


  • Helpful when biggest symptoms include low energy and concentration issues
  • Not known to have sexual side effects like the vast majority of other antidepressants
  • Can actually be added to existing medication to treat sexual side effects

  • In patients with high anxiety or irritability, it may make these symptoms worse
  • Cannot be used in anyone with a seizure disorder or eating disorder

Remeron (mirtazapine) is another novel agent, working on “alpha” receptors in the brain.


  • Helpful in patients with insomnia. At its lowest dose, it can be somewhat sedating.

  • Weight gain in a small portion of patients, though generally only at the lowest dose.

Which Antidepressant Is Right For Me?

Is there a perfect pill for everyone? We wish. We’d invest in that company in a heartbeat. That’s why there are so many options – so your mental health prescriber can find the one that works for you.

That’s assuming medication is the right choice for you. That’s also something to talk over with your local mental health prescriber. They’re really the best source of information, as they know you, your health, and your situation. They can also walk you through the process and ease some anxieties you might have, and they can even translate some of the often-intimidating clinical language.


Lida Turner, MD is a psychiatry contributor to Take This Project. She is a graduate of the University of Washington Medical School and practices general psychiatry in the Seattle-area. In her spare time, she is an avid hiker, ruthless Settlers of Catan player, and admits to being “obsessed” with Final Fantasy and Kingdom Hearts.