What are Antidepressants for?
Antidepressants are psychiatric medications that can help relieve symptoms of depressive disorders and anxiety disorders, as well as other mental health disorders [1].
What is the Science behind it?
They aim to correct chemical imbalances of neurotransmitters in the brain, that are believed to be responsible for changes in mood and behaviour, by increasing its activity.
Different Types of Antidepressants
Second-generation Antidepressants
Generally, second-generation antidepressants, and those with similar mechanisms that selectively target neurotransmitters, are the first line of treatment for depressive disorders.
Selective Serotonin Reuptake Inhibitors (SSRIs)
SSRIs are the most commonly prescribed antidepressants. They block the reuptake (i.e., absorption) of serotonin in the brain. This makes it easier for the brain cells to receive and send messages, resulting in better and more stable moods.
Examples of SSRIs include citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac, Sarafem), fluvoxamine (Luvox), paroxetine (Paxil) and sertraline (Zoloft) [2].
Serotonin and Noradrenaline Reuptake Inhibitors (SNRIs)
Licensed practitioners also commonly prescribe SNRIs for major depression and mood disorders. SNRIs raise levels of serotonin and norepinephrine, two neurotransmitters in the brain that play a key role in stabilising mood, which help lessen symptoms of anxiety and depression [3].
Examples of SNRI antidepressants include Venlafaxine, Duloxetine, Desvenlafaxine, Milnacipran, and Levomilnacipran [4].
First-generation Antidepressants
Tricyclic Antidepressants (TCAs)
Tricyclic and tetracyclic antidepressants (TCAs), also called cyclic antidepressants, are among the earliest antidepressants developed. They are effective, but they have generally been replaced by second-generation antidepressants that cause fewer side effects. However, TCAs may be a good option for some people — in certain cases, they relieve depression when other treatments have failed [5].
Like most antidepressants, TCAs increase levels of concentration of neurotransmitters, serotonin and norepinephrine, by preventing the reabsorption of these neurotransmitters. This helps to regulate mood and relieve depression symptoms. However, due to the severe adverse effects (refer to ‘side effects‘), they are typically not used as the first line of treatment [6].
Examples of TCAs include Amitriptyline, Clomipramine, Desipramine, Doxepin, Imipramine, Nortriptyline, Amoxapine, Protriptyline, and Trimipramine [7].
Monoamine Oxidase Inhibitors (MAOIs)
MAOIs are one of the earliest types of antidepressants used to treat various disorders including different types of depressive disorders, panic disorder, social phobia and depression with atypical features.
MAOIs serve to retain levels of neurotransmitters such as norepinephrine, serotonin, dopamine and tyramine by preventing monoamine oxidase enzymes from breaking these neurotransmitters down. This allows the neurotransmitters to continue interacting with cells affected by depression.
However, doctors rarely prescribe MAOIs as the first line of treatment due to the severity of possible side effects and strict dietary requirements [8].
Examples of MAOIs include Tranylcypromine, Phenelzine, Selegiline and Isocarboxazid [7].
How Effective are Antidepressants?
The effectiveness of antidepressants varies for different people, just like how different types of medication for physical illnesses vary in their effects on individuals according to the way their bodies react to the medication.
Antidepressants are used mainly to alleviate symptoms rather than function as a cure. This means that while these medications reduce symptoms of low mood or help a person sleep better, it is most effective in helping someone struggling with a mental health condition when coupled with therapy to treat a mental disorder.
Doctors usually recommend patients antidepressants when they struggle with prolonged and severe mental health conditions. However, this is seldom the first resort as these forms of medication can easily cause a person to become reliant on it.
What are the Possible Side Effects?
Potential side effects of the drug include [9]:
- Nausea
- Rash
- Dry mouth
- Constipation or diarrhoea
- Weight loss
- Sedation
- Sexual dysfunction
- Insomnia
- Dizziness
- Anxiety and agitation
- Abnormal thinking
However, consuming first-generation antidepressants (MAOIs and TCAs) generally pose higher risks of causing more severe effects compared to the second-generation counterparts (SSRIs and SNRIs).
MAOIs, when consumed with certain foods containing tyramine, can cause a large increase in blood pressure leading to stroke [10]. TCAs also tend to cause dry eyes, urinary retention, orthostatic hypotension [11], cardiovascular complications such as arrhythmias, and sudden cardiac arrests [12], and increased risk of suicide ideation [13]. Using TCAs during pregnancy is also correlated with congenital eye, ear, face, and neck defects [14].
As such, doctors seldom prescribe MAOIs and TCAs as first-line treatment of mental disorders due to their adverse and hard to manage side effects.
FAQ
1. How do antidepressants actually work?
40% of people treated with antidepressants usually see improvement within 2-4 weeks after their first trial with the medication. Nevertheless, it is important to keep in mind that everyone responds differently to medication. Most people will eventually find a type of antidepressant that works for them. Though the majority generally notice their sleep and appetite getting better first before their mood and energy.
If your symptoms are not improving or you are experiencing serious side effects, your doctor may adjust your dosage or change your medication.
2. Will antidepressants make me suicidal?
When a person first starts an antidepressant, they might feel worse before feeling better [15]. There is a period between starting an antidepressant and before symptoms start to lift — that may last up to a month — where individuals are at increased risk of engaging in harmful behaviours. This is because when a person starts an antidepressant, they experience a bout of energy that might prompt them to act on their impulses.
This could be due to the effect of SSRIs upon consumption. SSRIs affect the brain by releasing two chemicals — serotonin, which is released very soon after an SSRI is taken, but does not alleviate depressive symptoms until a few weeks; and glutamate, which usually takes a few days before it is fully released into an individual’s system. These two chemicals take effect at different times, resulting in a period of negative and vulnerable mental health. This might lead to a higher risk of acting on suicidal impulses [16].
However, one may not necessarily act on suicidal thoughts, nor will antidepressants always lead to suicidal thoughts. It is important to know that these side effects typically do not last longer than the first week. Nevertheless, you should always bring up any concerns or worries with your doctor at the earliest possibility.
3. When will I be prescribed antidepressants?
Antidepressants are usually prescribed alongside talk therapy to help manage the symptoms of mental health disorders [16].
Your mental health professional might suggest antidepressants if you have a more severe and prolonged condition, and they discern that you would benefit from medication which helps to balance internal hormonal and neurotransmitter levels in order to position you to be at a healthier baseline, to have the capacity to work through deeper-seated root issues and implement lifestyle changes.
