Depression can be experienced in completely different ways, depending on each person. The same goes for treatment—just because something worked for someone you know doesn't mean it will work for you too.
Additionally, a single treatment isn't always enough to alleviate symptoms. It's common to combine different medication classes or formulations, or to try more than one, to understand the best option for each case, since not every body responds the same way.
I want to remind you that the techniques we've learned throughout this journey are part of CBT (Cognitive Behavioral Therapy), a non-pharmacological treatment option that can be recommended independently or combined with medication.
When we look at the main drugs currently available on the market, we have:
Selective Serotonin Reuptake Inhibitors (SSRIs)
SSRIs are the most commonly prescribed antidepressant medications and tend to have few side effects. They treat depression but can also be used to treat anxiety. They work by increasing the availability of the neurotransmitter serotonin in the brain.
Serotonin is a neurotransmitter, but it's popularly known as the happiness hormone, with an extremely important function: maintaining communication between different nerve cells and brain and body regions related to regulating heartbeat, intestinal function, sleep, mood, appetite, memory, among others.
Some side effects of SSRIs may include:
- Sexual dysfunction
- Nausea
- Diarrhea
- Headache
- Short-term weight loss
- Long-term weight gain
- Forgetfulness
- Easy bruising
Norepinephrine-Dopamine Reuptake Inhibitors
This type of medication can treat depression by increasing both dopamine and norepinephrine levels. Both are also neurotransmitters, like serotonin, linked to related functions such as mood and memory, but with specific actions.
Just to clarify, since we're talking about neurotransmitters, they all act as chemical messengers, carrying and balancing signals between neurons and other cells in the body. These signals can aim to either stimulate or inhibit cells in their own functions and characteristics.
Dopamine, in this case, is linked to the regulation of emotions, cognition, and learning. It stimulates the brain to complete tasks and also acts in movement control, which is why Parkinson's disease is linked to the death of cells in a brain region responsible for synthesizing dopamine. The sensation of pleasure also comes from dopamine, which is why its release is connected to addictive drugs.
Norepinephrine, on the other hand, is more related to our ability to stay alert and have good memory. It's responsible for our ability to respond quickly in stressful situations, as its release increases blood pressure and vasoconstriction.
Norepinephrine-dopamine reuptake inhibitors are commonly used for depression in people who also have attention deficit hyperactivity disorder, cocaine use disorder, or who are trying to quit smoking.
Common side effects include:
- Headache
- Agitation
- Withdrawal syndrome
- High blood pressure
Serotonin Modulators (5-HT2 Blockers)
This type of medication is what we call a tetracyclic antidepressant, a medication with few side effects that works by increasing the amount of serotonin, known as the pleasure hormone, and norepinephrine in the brain.
The most common side effects are:
- Apathy
- Weight gain
- Drop in blood pressure when standing up
Heterocyclic Antidepressants
Heterocyclic antidepressants (including tricyclics) treat depression by also increasing the amounts of serotonin and norepinephrine, and to a lesser extent may affect dopamine release, thus acting on mood regulation, concentration, attention, and memory. They can also be useful in treating chronic neuropathic pain.
The issue is that this class of antidepressants has many side effects, the main one being cardiotoxicity—meaning they can cause arrhythmias and harm the heart. Therefore, they're not recommended for elderly patients, since older people are more susceptible to such effects.
Other side effects may include:
- Drowsiness
- Weight gain
- Increased heart rate
- Drop in blood pressure when standing up
- Dry mouth
- Confusion
- Blurred vision
- Constipation
- Difficulty starting urination
- Delayed orgasm
- Withdrawal syndrome
Monoamine Oxidase Inhibitors (MAOIs)
MAOIs treat depression by causing an increase in levels of norepinephrine, serotonin, dopamine, and tyramine, which is linked to blood pressure regulation in the brain.
Similar to heterocyclics, they also have many side effects, which is why MAOIs are not the first choice for treating mental disorders. Generally, they're used as a last resort, only if other medications really don't work.
People who use MAOIs need to follow certain dietary restrictions and avoid using some medications to prevent a bad interaction between them, which could cause a sudden and severe increase in blood pressure. There are now patch options that are safer and don't require as many precautions.
Among the most common side effects, we have:
- Insomnia
- Nausea
- Weight gain
- Sexual dysfunction
- Tingling sensation
- Dizziness
- Drop in blood pressure when standing up
- Withdrawal syndrome
These are some of the most common medication classes used in treating depressive symptoms, but only a doctor can analyze each case individually to prescribe the best option, weighing all the pros and cons together with each patient.
It's very important to have shared decision-making between clinician and patient when medication use is necessary, because it's not just about starting to take a medication—later comes the stage of thinking about and deciding when and whether to stop taking it.
Therefore, never, I said never, use any medication without the supervision of a healthcare professional who specializes in the subject.