What Are SNRIs and Other Types of Antidepressants
SSRIs are only one type of antidepressant.
SSRIs are only one type of antidepressant.
Other classes include serotonin and noradrenaline reuptake inhibitors, usually shortened to SNRIs, tricyclic antidepressants and monoamine oxidase inhibitors. There are also antidepressants that do not fit neatly into those groups.
These names describe groups of medicines and aspects of how they work. They do not tell you which medicine is appropriate for you.
What are SNRIs?
SNRIs affect signalling involving serotonin and noradrenaline, two chemical messengers in the nervous system.
They can be used in the treatment of depression and, in some circumstances, anxiety or other conditions.
Knowing that a medicine is an SNRI helps explain its drug class. It does not predict your personal response, side effects or how long you should take it.
What about older antidepressant classes?
Tricyclic antidepressants and monoamine oxidase inhibitors are established antidepressant classes.
Some older antidepressants are now used less commonly for depression than SSRIs because prescribing decisions also take account of matters such as side effects, interactions and safety.
That does not mean an older class is automatically unsuitable. The reason a particular medicine has been prescribed is an individual clinical question for your prescriber.
Why are there so many different antidepressants?
People do not all respond to treatment in the same way.
NICE guidance asks clinicians to consider benefits, possible harms, side effects, interactions, previous treatment, other health conditions and the person’s preferences when making prescribing decisions.
Different options allow treatment to be considered in the context of the individual rather than assuming one medicine suits everybody.
Do class names tell me which is stronger?
No.
It is not helpful to think of antidepressant classes as a simple ladder from weak to strong.
They work in different ways and have different prescribing considerations. A medicine being offered after another treatment does not necessarily mean your condition has become more severe.
What should I ask if I do not recognise the type I have been prescribed?
Ask your pharmacist, GP or prescribing clinician what class the medicine belongs to, why it has been suggested and what information is particularly relevant to your prescription.
You can also read the patient information supplied with the medicine.
Do not compare medicines or change treatment based on class descriptions alone.
Last reviewed
6 September 2026
Important medication and mental health information
This guide provides general information only and is not medical advice. It is not intended to recommend any particular medicine, treatment, dose, change to medication or course of action.
Medicines can affect people differently. The appropriate treatment will depend on your individual circumstances, health, other medicines you take and the reason treatment has been prescribed.
Do not start, stop, reduce, increase, change or switch prescribed medication based on information in this guide. If you have questions or concerns about your medication, side effects, missed doses, withdrawal symptoms or whether treatment is helping, speak to your GP, prescribing clinician, pharmacist or another appropriately qualified healthcare professional.
Some medicines used in mental-health treatment can be associated with dependence or withdrawal symptoms. Do not change or stop prescribed medication without professional advice.
If you think you may be experiencing a serious reaction to medication, seek urgent medical advice.
If you or somebody else is in immediate danger or there is a life-threatening emergency, call 999 or go to A&E. If you are experiencing a mental health crisis and need urgent help but it is not a life-threatening emergency, contact NHS 111 and select the mental health option, or use your local NHS urgent mental health service.