Updated: Aug 25, 2020
What is depression?
It’s a diagnosable condition that’s classified as a mood disorder and can bring about long-lasting symptoms such as overwhelming sadness, low energy, loss of appetite, and a lack of interest in things that used to bring pleasure. Left untreated, depression can lead to serious health complications, including putting your life at risk. Fortunately, there are effective treatments for depression through options like therapy, medication, diet, and exercise.
One of the most effective treatments used is medication, so how does medication help? Antidepressants work by balancing the levels of the chemicals in your brain called neurotransmitters; the main one being serotonin as it is closely linked to your mood. Neurotransmitters may also affect pain signals sent by nerves, which may explain why some antidepressants can help relieve long-term pain. While antidepressants can treat the symptoms of depression, they do not always address their causes. This is why they're usually used in combination with therapy to treat more severe depression or other mental health disorders. It usually takes about 3-4 weeks to notice changes while taking antidepressants. There are three main types of antidepressants that will be discussed in this article; MAOIs, NDRIs and SARIs. Some anxiolytics discussed in the other article can also be prescribed for depression such as SSRIs and SNRIs.
Monoamine oxidase inhibitors (MAOIs)
MAOIS were the first type of antidepressants to be developed, the use of MAOIs typically requires diet restrictions because they can cause dangerously high blood pressure when taken with certain foods or medications. An enzyme called monoamine oxidase is involved in removing the neurotransmitters norepinephrine, serotonin and dopamine from the brain. MAOIs prevent this from happening, which makes more of these brain chemicals available to effect changes in both cells and circuits that have been impacted by depression. MAOIs are sometimes used to treat conditions other than depression, such as Parkinson's disease.
Rarely, an MAOI can cause dangerously high levels of serotonin, known as serotonin syndrome. It most often occurs when two medications that raise serotonin are combined. These include other antidepressants, certain pain or headache medications. A dangerous interaction can occur when a patient on MAOIs eats foods rich in the amino acid tyramine. Normally, the monoamine oxidase enzyme keeps tyramine at safe levels in the body. But when the enzyme is inhibited by MAOIs, tyramine metabolism is inhibited, and the amino acid may build up to excessive levels. Some foods high in tyramine that you should avoid if you are consuming MAOIs are cured meats, alcoholic beverages, pickled or fermented foods, soybeans and strong or aged cheese.
Some side effects that you may feel while on MAOIs:
Nausea, diarrhoea or constipation
Dizziness or lightheadedness
Norepinephrine and dopamine reuptake inhibitors (NDRIs)
NDRIs function primarily by inhibiting the reuptake of dopamine and to a lesser degree the reuptake of norepinephrine. It is known for producing a short-term euphoria as a result of increased dopamine. Reuptake refers to the reabsorption of a secreted substance by the cell that originally produced and secreted it. Reuptake usually affects serotonin levels. It can be used to treat ADHD, energy levels among individuals with fatigue, as well as to improve symptoms of depression. Some NDRIs has been withdrawn from markets due to abuse potential, but many are considered safe and well-tolerated.
Serotonin antagonist and reuptake inhibitors (SARIs)
SARIs are used as a treatment for major cases of depression, they can also be used to treat other conditions such as anxiety, psychomotor agitation and insomnia. They are most likely to be prescribed as a sedative, SARIs inhibit a certain serotonin receptor—known as the 5HT2a receptor—and block the function of the serotonin transporter protein, thereby increasing the amount of active serotonin throughout the central nervous system (CNS). The immediate effect on insomnia and anxiety but may take 2-4 weeks to have an effect on depression. There are two types of SARIs: Trazodone (previous trade names include Desyrel, Oleptro) and Nefazodone (previously marketed as Serzone).
Some side effects that you may feel while on SARIs:
Writer: Rhea Rangarajan
Illustration: Sarah Samad