What Are SSRIs and Why Are They Prescribed
SSRIs are selective serotonin reuptake inhibitors, a class of antidepressant medicines.
SSRIs are selective serotonin reuptake inhibitors, a class of antidepressant medicines.
They are used in the treatment of depression and can also be prescribed for some other mental-health conditions.
The name describes how the medicines affect serotonin signalling. It does not mean that somebody’s mental-health difficulty can be reduced to a simple serotonin deficiency, and it does not tell you whether an SSRI is the right treatment for you.
Why are SSRIs commonly discussed?
NHS information describes SSRIs as a commonly used type of antidepressant.
Clinicians consider a range of factors when discussing medication, including the condition being treated, possible benefits and harms, side effects, interactions, previous treatment, other health conditions and the person’s preferences.
Being commonly prescribed does not make a medicine suitable for everybody.
What does ‘selective serotonin reuptake inhibitor’ mean?
Serotonin is one of the chemical messengers involved in communication within the nervous system.
SSRIs change serotonin signalling by inhibiting its reuptake.
That is a description of a pharmacological action, not a complete explanation of depression, anxiety or why one individual improves with treatment and another may not.
Are all SSRIs the same?
No.
Medicines within the same class share broad characteristics but can differ in interactions, side effects, withdrawal considerations and other prescribing factors.
MH360 avoids comparing individual products or suggesting which medicine might be preferable. Those are questions for a qualified prescriber who knows your circumstances.
What might I want to understand if I have been prescribed one?
You may want to ask why the medicine has been offered, what symptoms or difficulties it is intended to help, what unwanted effects you should know about, when treatment will be reviewed and who to contact if you have concerns.
You can also ask a pharmacist about medicine information and the instructions supplied with your prescription.
These questions help you understand treatment without trying to manage the prescription yourself.
What if I am worried about taking an SSRI?
Tell the prescriber what worries you.
Concerns about side effects, dependence, withdrawal, long-term treatment or previous experiences with medication are legitimate subjects for a clinical conversation.
Do not start, stop or change prescribed medication because of something you have read in a general guide. Use the information to help you ask informed questions of the professional responsible for your care.
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.
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.