The Science Behind Antidepressants – Understanding Your Medication

Perhaps you’re feeling a bit nervous about starting antidepressants, or you’ve been on them for a while and just want to know how they work. The science behind antidepressants is fascinating, and has helped millions of people to lessen their mental illness symptoms. 

What Are They For? 

As the name suggests, they are most commonly used to ease the symptoms of depression. However, they are also a useful tool for the treatment of anxiety, PTSD, OCD and eating disorders. 

Medications are not the only option for treating these disorders. Typically, the first line of defense is lifestyle changes such as exercise and diet, followed by psychotherapy. However, if these strategies are unsuccessful, professionals often turn to antidepressants. When used as part of a holistic approach, they have a fairly high success rate. 

How Do They Actually Work?

To understand the mechanisms behind this medication, we need to dive into how the brain communicates. 

Neurons

The brain and nervous system communicate using a type of nerve cell called a neuron. Think of this as a network of connected wires. One neuron is connected to many, many others, which are connected to many more, and so on. When the brain needs to communicate, such as when you perceive stimuli, think, or perform an action, an electrical signal is sent down a neuron. 

The electrical signal starts at the dendrites, the little branches on the left side of the photo above. It then travels down the cell body, all the way to the axon terminal (the end of the neuron). 

You’ll see at the very end of the axon terminal, is the synapse. This is really the space between one neuron and the next. This is where the magic happens. 

When the electrical signal reaches the synapse, a bunch of chemicals, called neurotransmitters, are released. These latch onto the next neuron, telling it to send it’s electrical signal forward, and the cascade continues. 

The Synapse

When the neurotransmitters (little yellow dots) have done their job by communicating with the next neuron, they are either brought back into the original neuron (reuptake) or broken down by enzymes in the synapse. Stay with me – we’re almost to the antidepressant part.

Two neurotransmitters called serotonin and norepinephrine are important for mood, executive function, energy levels, and more. Lower levels of these neurotransmitters have been associated with many mental illnesses. 

What Do Antidepressants Have to Do With It?

The two most common types of antidepressants are SSRIs and SNRIs. Now that we have some background information, it’s easier to understand what these actually mean.

SSRI stands for selective serotonin reuptake inhibitor. Let’s break down that name. 

Serotonin: One of your mood-boosting neurotransmitters 

Reuptake: When the neurotransmitter is brought back into the neuron 

Inhibitor: Stops an action from happening

When we put this all together, it really means that the drug is stopping the serotonin from going back into the neuron. This allows for the neurotransmitter to build up in the synapse. Over time, this eases symptoms of mental illness. Some common SSRIs are Lexapro, Prozac and Zoloft. 

SNRIs work nearly the same way. Serotonin and Norepinephrine Reuptake Inhibitors not only block serotonin from re-entering the cell, but norepinephrine too. Some SNRIs you may have heard of are Effexor and Fetzima. 

In short, they increase the amount of neurotransmitters available to your brain. 

How Long Does It Take?

Unfortunately, this is a bit of a slower process. It usually takes around 4-6 weeks to start noticing a difference when on antidepressants, though this can vary. Building up the chemical levels in your brain doesn’t happen instantaneously, which is why it takes a while to kick in. 

Side Effects

Both types of medications are pretty well tolerated by most. Typical side effects go away within a few weeks as your body adjusts to the drug. The most common include nausea, headaches, dry mouth, fatigue, decreased appetite and dizziness. Many of these can be eased by changing the time of day you take your medication. Some find they tolerate it best right after a meal, some on an empty stomach. If they make you fatigued, you can take them at night! If they keep you awake, take them in the morning. 

Is It Worth It?

It’s hard to predict what medication is right for you. There’s typically some trial-and-error involved as you find the right combination. The good news is that many individuals see a reduction in symptoms.

It’s important to keep in mind that medication often has the best results when used in conjunction with therapy (Voderholzer et al., 2024). Book a consultation with our counsellors here to learn more about therapeutic options for the treatment of mental illness. 

Source:

Voderholzer, U., Barton, B. B., Favreau, M., Zisler, E. M., Rief, W., Wilhelm, M., & Schramm, E. (2024). Enduring effects of psychotherapy, antidepressants and their combination for depression: a systematic review and meta-analysis. Frontiers in Psychiatry, 15. https://doi.org/10.3389/fpsyt.2024.1415905