Antidepressants: What are they, and how do they work?

By Dr. Gretchen KubackyDepression

If you struggle with depression or anxiety, you may have heard your psychologist (or a partner, or a particularly nosy friend) recommend taking antidepressant medication. But what exactly are antidepressants, and how do they work? And what might be some other alternatives?

Before we get into the nitty-gritty details of how antidepressants work, we first need to discuss some basic brain anatomy. As you may know, brain cells are called neurons, and while there are many types of neurons, they share a basic structure. Branching off from the cell body are various branches (like on a big oak tree) called dendrites. At various points along each dendrite it will touch the dendrites of other neurons, and these points of connection are called synapses. Think of a synapse as like two hands meeting for a handshake. Neurons communicate together by passing special chemicals called neurotransmitters from one cell to another through these synapses. The neurotransmitters most commonly implicated in depression and anxiety are serotonin, dopamine, and norepinephrine.

Some theories argue that depression and anxiety are caused, in part, by deficiencies of these mood-related neurotransmitters in certain parts of the brain. Antidepressant medications aim to help correct this by boosting levels of these neurotransmitters. When one neuron signals another, it releases a neurotransmitter into the synapse, or into the tiny space between where the two dendrites touch, which then pass into the other neuron. After a short time, excess neurotransmitter molecules are vacuumed back up by the first neuron in a process called reuptake. Antidepressants often work by inhibiting this reuptake process, which boosts the overall amount of neurotransmitter molecules in the synapse, which (in theory) aids neural signaling and can ease depression and anxiety symptoms.

The most common types of antidepressant medications, therefore, are named after this process and the type(s) of neurotransmitters they work on. For instance, the most common type of antidepressant medication is called a Selective Serotonin Reuptake Inhibitor (SSRI). Other common types include Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs) and Norepinephrine-Dopamine Reuptake Inhibitors (NDRIs). In addition, there are numerous other less-common types of medications, such as mood stabilizers, tricyclic and tetracyclic antidepressants, and atypical antipsychotics (so named because, at higher doses, they are used to treat schizophrenia and related disorders). Antidepressant medications are generally well tolerated, but common side effects include difficulty with sexual arousal or orgasm, minor weight gain, and upset stomach.

If you are suffering from depression or anxiety, it is important to consult with a licensed and qualified psychiatrist or psychiatric nurse practitioner about the benefits and drawbacks of these medications, and to find the right one for you. Often, several medications may need to be tried in order to find one that works well with no, or very few, side effects. Don’t worry, this is normal! While general practitioner doctors can prescribe antidepressants, they often have less training and knowledge about them than specialists such as psychiatrists.

It is important to note that prescription medications are far from the only effective treatment for depression! First off, psychotherapy with a qualified and licensed psychologist (like me!) has been proven to be effective at treating depression and anxiety. In particular, psychotherapy plus medication are often more effective than either one alone.

Second, regular aerobic exercise has been shown to be practically as effective as antidepressant medications, with the only “side effects” being better health, reduced weight, and improved cardiovascular functioning!

Finally, there are a number of over-the-counter supplements that you can take which have antidepressant effects. These include Sam-E, St. John’s Wort, and 5-HTP. Some of these supplements may have their own side effects or may interact with other medications you are taking, so make sure to ask your doctor or psychiatrist first before starting to take them!

Depression and anxiety are very common problems that many people struggle with at various points in their lives. If you believe you may suffer from these conditions, please know that it does not mean there is anything “wrong” with you, and remember that successful treatment is possible! Speak to your psychologist and doctor about your concerns and get the help you deserve!



Bet, P. M., Hugtenburg, J. G., Penninx, B. W. J. H., & Hoogendijk, W. J. G. (2013). Side effects of antidepressants during long-term use in a naturalistic setting. European Neuropsychopharmacology, 23(11), 1443–1451.

Blumenthal, J. A., Smith, P. J., & Hoffman, B. M. (2012). Opinion and evidence: Is exercise a viable treatment for depression? ACSM’s Health and Fitness Journal, 16(4), 14–21.