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What different types of antidepressants are available?

Antidepressants are medicines that are designed to treat clinical depression but can also be used to treat conditions such as Obsessive-Compulsive Disorder (OCD), Post-traumatic Stress Disorder (PTSD) and Generalised Anxiety Disorder.

It isn’t known exactly how antidepressants work but they are thought to increase the levels of chemicals in the brain called neurotransmitters (, 2018). Some neurotransmitters are linked to our emotions and mood, so it is thought that increasing the levels of these can impact how we feel.

Antidepressants can help to ease some of the signs and symptoms of depression, but they don’t deal with the causes. Your doctor may therefore recommend that you also undertake therapy, alongside taking medication for your clinical depression.

There are currently many different antidepressant medications available, and they fall into a few different types, which include:

Selective serotonin reuptake inhibitors (SSRIs)

Antidepressant tablets that fall into this type include FluoxetineCitalopramParoxetine and Sertraline. It is thought that they work by increasing the levels of serotonin in the brain, which is a neurotransmitter that is thought to have an influence on things like sleep, mood and emotion (, 2018).

Selective serotonin and noradrenaline reuptake inhibitors (SNRIs)

These are antidepressants that act in a similar way to SSRIs but act particularly on the serotonin and noradrenaline neurotransmitter levels in the brain (, 2014). Medications from this group of antidepressants include Venlafaxine.

Atypical antidepressants

Atypical antidepressants are medications that don’t fit into one of the other classifications. They can work differently to each other, but ultimately, they increase the levels of specific neurotransmitters that are thought to regulate mood. Medications in this category include Mirtazapine and Trazadone.

Noradrenaline and specific serotonergic antidepressants (NASSAs) and tricyclic antidepressants (TCAs)

These are the types of antidepressants that are not usually recommended as the first treatment for depression as they can have more unpleasant or serious side effects, but if other types of antidepressants do not prove to be effective for you, you could be prescribed one of these types of medication instead (, 2018).

What are the most popular types of antidepressant medication?

The most widely prescribed antidepressants are SSRIs. They are often preferred to other types of antidepressants because they tend to cause fewer side effects (, 2018).

As it is not fully known how antidepressants work, and every patient’s body and mind are unique, it can be the case that a type of antidepressant medication has a different effect on one person to the next. Some patients will find specific medicines are more effective for treating their clinical depression than others, and it usually takes at least one-two weeks of taking the prescribed dose for patients to feel any benefits from the antidepressant medicine they are taking.

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What is the strongest type of antidepressant?

When you are first prescribed an antidepressant, you will be started on the lowest dose that your doctor thinks will be necessary to improve your symptoms. This approach is to help reduce the risks of you experiencing side effects. If your current antidepressant treatment does not seem to be improving your symptoms after giving it the recommended amount of time, consult your doctor, who may suggest an alternative treatment that is suitable for you.

As medications can affect people in different ways, there is no single antidepressant treatment that is the right fit for every patient, nor one dosage level that works for everyone. Finding the most effective way to treat your clinical depression can sometimes take some time and you should speak to your doctor if you have concerns about your condition.

Side effects of the different types of antidepressants

Whilst every antidepressant medication is different, there are some common side effects that some people may experience:

Side effects when taking SSRIs and SNRIs can include:

  • Feeling shaky, anxious or agitated
  • Feeling nauseous or vomiting
  • Dizziness
  • Drowsiness or problems sleeping (insomnia)
  • Constipation or diarrhoea
  • Indigestion or stomach aches
  • Loss of appetite
  • Lower sex drive than normal
  • Erectile dysfunction in male patients

Side effects when taking TCAs can include:

  • Dizziness or drowsiness
  • Dry mouth
  • Weight gain
  • Heart palpitations or a fast heartbeat
  • Minor blurring of vision
  • Constipation or difficulty passing urine

In most cases, side effects will lessen or disappear after a couple of weeks of taking the medication.

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Side effects if you stop taking antidepressants suddenly

You shouldn’t stop taking antidepressants suddenly, even if your symptoms improve and you feel better. Most antidepressants are prescribed as a six-month course initially and may be continued after this, if you and your doctor feel that it is required. When you do stop taking your antidepressant medicine, it should be done on your doctor’s advice, with a gradual reduction in dosage over several weeks.

If you stop taking your antidepressants suddenly, the side effects could include:

  • Flu-like symptoms
  • Stomach upsets
  • Anxiety
  • Dizziness
  • Seizures (fits) or sensations in the body that feel like electric shocks
  • The return of your original symptoms of depression

View the types of antidepressants available.

References:, (2014). Selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors (SNRIs): use and safety. [Online] [Accessed 10 May 2019]. Available at:

Nhs UK., (2018). Antidepressants. [Online] [Accessed 10 May 2019]. Available at:

Nhs UK., (2018). SSRIs. [Online] [Accessed 10 May 2019]. Available at:

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