Antidepressants: How does it work?

The use of medication to manage symptoms of mental illness has improved a lot since its inception in the mid 20th century. This blog hopes to answer some of the common questions about psychiatric medication specifically focusing on how antidepressants work.

Neurotransmitters

Neurotransmitters are chemicals in your brain that carry signals between cells. There are many different types of neurotransmitters such as Dopamine, Serotonin and Noradrenaline etc., which are thought to have some sort of affect on your mood. Different body functions are controlled by different neurotransmitters, and we are yet to discover and fully understand which neurotransmitter is responsible for depression. Antidepressants, in essence, increases the amount of certain neurotransmitters in the brain, which is believed to subdue some of the symptoms of depression.

Types of antidepressants

There are many classes of antidepressants grouped according to how they work. Within each class, there are a variety of drugs. For these medications to be approved for consumption, they go through rigorous clinical trials. The type of antidepressant prescribed to you will completely depend on you and your context. Your psychiatrist or general practitioner will consider your age, medical condition, allergies and other medication you may be on (some medicines can interact with each other). It’s important to remember that no antidepressant is “stronger” than the other. When tested, each type is of an approximately similar effect as the other. However, different individuals respond differently to each antidepressant. It is vital to find one that works best for you, and it may be the case that the only way to find the best one is through trial-and-error.

Here are some types of antidepressant classes:

  • Selective serotonin reuptake inhibitors (SSRI’s)
  • Serotonin and noradrenaline reuptake inhibitors (SNRI’s)
  • Noradrenaline reuptake inhibitors
  • Tricyclic antidepressants (TCA’s)
  • Reversible inhibitors of monoamine oxidase A (RIMA’s )
  • Tetracyclic antidepressants
  • Tetracyclic analogues of mianserin are sometimes called noradrenergic and specific serotonergic antidepressant (NaSSA)
  • Monoamine oxidase inhibitors (MAOI’s)
  • Melatonergic antidepressants

Puzzles in the synaptic cleft

Neurotransmitters move between neurons (brain cells) through the synaptic cleft (a space
between the two neurons). The neurotransmitter will be released from one axon, through the synaptic cleft, and to the waiting dendrite of the next neuron. Just like the shape fitting puzzle you played as a child, the neurotransmitter goes to specific matching receptor sites. 

Medication will interact with these matching sites to either prevent or enhance the re-uptake of the neurotransmitters. As medication is not perfect, it does not fit perfectly into the “shapes” and therefore could trigger other bodily systems resulting in side effects. Different people respond differently to different drugs. It is always important to discuss any potential side-effects with your health care provider.

Long term use of antidepressants

Often you feel begin to feel the effects after 2 weeks of taking antidepressants, but sometimes treatment can go as long as 8 weeks for the full effect to be felt. Again, it depends on the way your body reacts to the antidepressants that determine the rate at which they will begin to work. It’s important to stay in contact with your health care worker to make certain that optimum results are being obtained. In cases where no results are felt after a certain time frame, advise your psychologist and they will work with you to find an alternative solution.

Treatment usually lasts between 6-12 months once an antidepressant that works has been established. Some choose to stay on the medication for longer time periods, while others choose to live without them. Generally, the effects of antidepressants last longer if therapy is done simultaneously.