How Do Antidepressants Work?

Published: July 18, 2024

Depression affects millions worldwide, but the workings of antidepressants are complex and often misunderstood. Let’s see how these medications function, focusing on brain chemistry, neural pathways, and psychological processes.

Neurotransmitters: The Brain’s Chemical Messengers

Neurotransmitters, such as serotonin, norepinephrine, and dopamine, play a vital role in regulating mood, and antidepressants often target these chemicals to increase their levels in the brain. For example, selective serotonin reuptake inhibitors (SSRIs) like Prozac and serotonin-norepinephrine reuptake inhibitors (SNRIs) like Cymbalta prevent the reabsorption of serotonin and norepinephrine, respectively, making them more available in the brain.

Top 10 Medications for Anxiety and Depression

Types of Antidepressants & How They Work

Antidepressants come in various types, each designed to affect neurotransmitter levels differently. Understanding antidepressant types can help you and your healthcare provider choose the most appropriate medication for your needs.

Selective Serotonin Reuptake Inhibitors (SSRIs)

SSRIs are among the most commonly prescribed antidepressants. They work by increasing serotonin levels in the brain, as serotonin is a neurotransmitter that plays a vital role in mood regulation. By blocking the reabsorption (reuptake) of serotonin into neurons, SSRIs ensure more serotonin is available in the synaptic cleft, the space between neurons. Common SSRIs include:

Fluoxetine (Prozac)
Sertraline (Zoloft)
Paroxetine (Paxil)
Citalopram (Celexa)
Escitalopram (Lexapro)

Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs)

SNRIs increase levels of both serotonin and norepinephrine, another neurotransmitter involved in mood and anxiety regulation. By blocking the reuptake of these neurotransmitters, SNRIs enhance their availability in the brain, which can help improve mood and alleviate anxiety. Common SNRIs include:

Duloxetine (Cymbalta)
Venlafaxine (Effexor)
Desvenlafaxine (Pristiq)
Levomilnacipran (Fetzima)

Norepinephrine-Dopamine Reuptake Inhibitors (NDRIs)

NDRIs primarily affect the reuptake of norepinephrine and dopamine, two neurotransmitters that are critical for mood regulation, motivation, and reward processing. By increasing the levels of these neurotransmitters, NDRIs can help improve mood and energy levels. The most well-known NDRI is Bupropion (Wellbutrin).

Tricyclic Antidepressants (TCAs)

TCAs are an older class of antidepressants that block the reuptake of multiple neurotransmitters, including serotonin and norepinephrine. This makes more of these chemicals available in the brain. TCAs are often used when newer antidepressants have not been effective. However, they tend to have more side effects due to their broader mechanism of action. Common TCAs include:

Amitriptyline (Elavil)
Imipramine (Tofranil)
Nortriptyline (Pamelor)
Clomipramine (Anafranil)

Monoamine Oxidase Inhibitors (MAOIs)

MAOIs work by inhibiting the activity of monoamine oxidase, an enzyme that breaks down neurotransmitters like serotonin, norepinephrine, and dopamine. By preventing this breakdown, MAOIs increase the levels of these neurotransmitters in the brain. MAOIs are usually prescribed when other antidepressants haven’t worked due to their potential for severe interactions with certain foods and other medications. Common MAOIs include:

Phenelzine (Nardil)
Tranylcypromine (Parnate)
Isocarboxazid (Marplan)
Selegiline (Emsam)

How Antidepressants Promote Neuroplasticity

Antidepressants help the brain reorganize and form new connections through neuroplasticity. They increase the expression of brain-derived neurotrophic factor (BDNF), which supports neuronal growth and synaptic plasticity. This helps counteract the negative effects of chronic stress and depression on brain structure and function.

Can Antidepressants Treat Conditions Other Than Depression?

Yes, antidepressants can also treat various other conditions, including:

How Long Does It Take for Antidepressants to Work?

It’s important to note that antidepressants can take several weeks to show their full benefits. This delay occurs because these medications do more than just increase neurotransmitter levels—they also promote long-term changes in brain chemistry and structure, such as neuroplasticity. Patience and adherence to the prescribed treatment plan are essential, as discontinuing medication prematurely can prevent the full therapeutic benefits from being realized. Regular follow-ups with your healthcare provider can help manage expectations and adjust the treatment plan as needed.

Can I Combine Medication and Online Therapy?

Yes, combining medications with therapies like cognitive-behavioral therapy (CBT) and lifestyle changes can enhance depression treatment outcomes. Not everyone responds to antidepressants the same way. Personalized approaches consider genetic markers, neuroimaging, emotional processing, and environmental factors to optimize treatment. Methods like transcranial magnetic stimulation (TMS) and ketamine therapy offer additional options for those who don’t respond to traditional treatments.

Medication Treatment for Depression at MindRX

Understanding how antidepressants work involves exploring their effects on brain chemistry, neuroplasticity, and emotional processing. At MindRx, we integrate pharmacological and complementary therapies to offer personalized, compassionate care, as our goal is to empower individuals on their journey to mental well-being, fostering resilience and hope. Schedule a consultation today to learn more about our medication management services and how we can support you on your journey.