Selective serotonin reuptake inhibitors (SSRIs) are a group of antidepressant medications that are prescribed to treat depression and anxiety. 

  1. Treat depression and anxiety symptoms.
  2. The most well-known is paroxetine (Prozac).
  3. Can take several weeks before they are effective 

If you are concerned about your mental health, you can speak with one of our registered clinicians via our online video consultation service, from 9.30m-4.30pm, Monday to Friday. 

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What are SSRIs?

SSRIs are a group of antidepressant medications that treat various mental health conditions. They are primarily prescribed to treat depression and anxiety, although they have been known to be of some benefit to people with premature ejaculation or irritable bowel syndrome (IBS).

What is depression?

Depression is a potentially serious mental health condition. While everyone experiences low mood from time to time, depression is a persistent feeling of low mood that may endure for weeks or months at a time. 

What symptoms can depression cause?

Symptoms of depression present both mentally and physically. Psychological symptoms are usually the first to become noticeable and include low mood, sadness, tearfulness, hopelessness, guilt, a loss of pleasure in things you used to enjoy, being unable to make decisions, anxiety, a lack of motivation and low self-esteem. In more severe cases, this can lead to suicidal thoughts and a compulsion to self-harm. 

In terms of physical symptoms, some people may experience weight changes, digestive issues, slow movements and speech, low energy, loss of sex drive, general pains, insomnia, too much sleep and an altered menstrual cycle. These symptoms can lead to social anxiety, which may result in the development of avoidance behaviours, such as cutting yourself off from seeing family and friends, and putting a strain on your relationships.

Depression can be categorised as one of three severities, although these should only be seen as broad descriptors as everyone reacts differently to the condition and it is somewhat dependent on its cause. There is mild depression, which will have some impact on your day to day life, moderate depression, when the impact can be described as significant, and severe depression, where your day to day life becomes unmanageable. In some cases, severe depression can lead to psychotic episodes that may result in hallucinations, delusions and disturbed thoughts.

What causes depression? 

Causes of depression may vary from person to person, although there are some common triggers. The most obvious include life events, such as grief, the loss of a job, the end of a relationship and money troubles. Other common triggers include a family history of depression (some studies suggest a genetic component), your personality type, giving birth, loneliness, substance abuse (including alcohol and prescription drugs) and physical illness. In some cases however, it’s not clear what causes depression. 

How is depression diagnosed? 

Your doctor will ask you about your symptoms, as well as general questions about your lifestyle and relationships. Because there is no physical test to diagnose depression, blood and urine tests, for example, will only be taken if your doctor believes your symptoms are triggered by another condition.

How is depression treated? 

Treatment for depression will depend on a number of factors, such as its cause and severity. In cases where depression is mild, your doctor may suggest you make certain lifestyle changes and wait to see if you feel better over the course of a few weeks. This can include getting exercise and joining a self-help group. 

In cases of moderate depression, a talking therapy such as cognitive behavioural therapy (CBT) can be very effective in helping to manage symptoms and prevent them from getting worse. CBT seeks to address negative thought patterns, and alter the way that you think and behave. 

If symptoms for mild or moderate depression do not clear up, antidepressants are usually prescribed. Severe depression is often treated with antidepressants alongside a talking therapy from the outset due to the risks involved. This is called combination therapy. Other talking therapies include counselling (where you can discuss your problems with someone who can help you find solutions), interpersonal therapy (or IPT, which puts a focus on your relationships, including coping with grief) and psychodynamic psychotherapy (where a therapist can help you analyse your patterns of thought).

What types of antidepressants are available?

Antidepressants are available in many forms. Tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs) are older types that tend to present with more side effects, although they are effective in some cases. 

The newest type of antidepressants are serotonin and norepinephrine reuptake inhibitors (SNRIs), but the most commonly prescribed are selective serotonin reuptake inhibitors (SSRIs) due to the fact that SNRIs can lead to high blood pressure in some patients. Exactly what antidepressant is right for you may require some trial and error, and your prescribing clinician will look to reduce the risk of potential side effects as much as possible. Antidepressants can take several weeks to take effect, and your doctor will monitor how you are finding them, particularly during the first month or two of treatment.

What is anxiety?

Anxiety is a common and natural experience for anyone in certain circumstances, such as prior to a job interview, a wedding or while awaiting test results. In some cases, however, it can be more persistent, and impact on peoples’ day to day lives. Experiences of anxiety on a frequent basis can lead to the development of an anxiety disorder, such as panic disorders, phobias, post traumatic stress disorder (PTSD) and social anxiety disorder. 

The following information relates to generalised anxiety disorder (GAD) which is a sense of anxiety about a broad range of events and situations, as opposed to one specific situation or event. People who experience GAD feel anxious most of the time, and find it difficult to recall when they last felt at ease. 

What symptoms does generalised anxiety disorder cause? 

Symptoms of generalised anxiety disorder fall into two categories: psychological and physical. Psychological symptoms include feeling on edge, irritability, a sense of constant fear, restlessness and problems concentrating. These symptoms can lead to you becoming isolated as you seek to avoid stressful social situations. 

Physical symptoms can develop as a result of psychological symptoms, and include fatigue, dizziness, palpitations, shaking, aches and pains, nausea, problems breathing, headaches, sweating, a dry mouth and pins and needles. In most cases, these symptoms occur as a consequence of a specific trigger, such as a phobia of heights when up a ladder, or claustrophobia in confined spaces. For people with generalised anxiety however, these symptoms can appear without an apparent cause.

How is generalised anxiety disorder diagnosed?

If you experience symptoms of generalised anxiety disorder on a regular basis, you should speak to your clinician, who can help to diagnose the condition. They will ask you about your day to day life, if you have any worries or fears, your personal relationships, and your physical and mental wellbeing. Due to the fact that anxiety can be a symptom of a physical condition, such as an overactive thyroid, they may also want you to undertake some blood tests to rule out any other health conditions.

How is generalised anxiety disorder treated?

Before any treatment related to anxiety will be offered, your doctor will want to treat any underlying condition that may need to be addressed, such as alcoholism or depression. This may define the treatment you receive. Treatment for generalised anxiety disorder comes in two forms: psychological (talking therapies) and medication. 

Psychological treatments will likely include CBT, which has been proven to be more effective than medication for some people. Applied relaxation techniques have also proven to be beneficial in some instances; it involves focusing on relaxing your muscles under the guidance of a trained therapist over the course of three to four months. 

Medication for anxiety is usually in the form of an antidepressant; typically, an SSRI or SNRI. Another option is benzodiazepines, but they are not suitable for long term use due to the risks of addiction. 

If the techniques and medications above are not effective, a referral to a specialist, such as a psychiatrist or psychologist, may be considered.

If you would like to discuss SSRIs or any related conditions with a GMC-registered clinician, our online video consultation service is available from 9.30am-4.30pm, five days a week. Our clinicians can also provide referrals to specialists for treatment and fit notes, where appropriate.     

Page last reviewed:  22/07/2020
Side effects and warnings

What side effects can SSRIs cause? 

All medications come with some risk of side effects, and SSRIs are no exception. In most cases, these side effects subside as the body becomes accustomed to the changing levels of serotonin in the body, but some people may experience more long-term side effects. 

It is therefore important to understand what these risks are before starting treatment. Your doctor can discuss any potential side effects with you, and you can also refer to the patient information leaflet that comes with your medication for details. 

Because there are many different SSRIs, the information listed below may not be relevant for your treatment.

The following side effects relate to the SSRI Citalopram. You should stop using Citalopram and seek immediate medical attention if you experience: difficulty breathing, swelling of the face, lips, tongue or throat, difficulty swallowing or breathing, severe itching of the skin, a fast and irregular heart beat, fainting fits, behavioural changes such as elation, fever, agitation, confusion, trembling, contractions of the muscles, confusion and twitching of the muscles. 

If you experience any suicidal thoughts or a compulsion for self-harm, you should contact your doctor immediately or go to your nearest hospital.

Other side effects tend to subside after a few days and include: 

Very common (may affect more than 1 in 10 people): nausea, dry mouth, headaches, sweating, sleepiness, insomnia, changes in sleeping pattern and weakness.

Common (may affect up to 1 in 10 people): tremor, dizziness, migraine, decreased appetite, decreased weight, anorexia, agitation, anxiety, nervousness, confusion, decreased libido, sensation of tingling, pricking or numbness in skin, concentration issues, tinnitus, palpitations, diarrhoea, vomiting, constipation, indigestion, stomach pain, flatulence, increased saliva, muscle pain, joint pain, itching, fatigue, yawning, blocked or runny nose, an inability in women to achieve orgasm, menstrual pain, impotence, ejaculation failure, abnormal dreams, memory loss and an absence of emotion or enthusiasm.

Uncommon (may affect up to 1 in 100 people): slow heartbeat, fast heart beat, increased appetite, increased weight, aggression, detachment, hallucinations, mania, euphoria, increased libido, fainting, dilated pupils, hives, rash, hair loss, redness or red spots on the skin, photosensitivity, urinary retention, heavy menstruation and oedema. 

Rare (may affect up to 1 in 1,000 people): bleeding, major fits, involuntary movements, taste disturbances, liver inflammation, fever, coughing and feeling unwell. 

The following side effects have been reported but there is not enough data to suggest their frequency: reduced number of blood platelets, arrhythmia, allergies, SIADH (syndrome of inappropriate secretion of antidiuretic hormone), low levels of potassium, panic attacks, teeth grinding, restlessness, extrapyramidal disorder, feeling of restlessness, movement disorders,  vision disturbances, QT-prolongation, dizziness when standing, nosebleed, blood in the stools, abnormal liver function test, bruising, milk secretion from the breasts in men, painful and prolonged erection, irregular menstrual bleeding and increased risk of bone fractures. 

Can SSRIs cause interactions with other medications?

You should tell your doctor about any other medications you are taking before starting treatment with SSRIs, so that the medication can be prescribed safely. This includes herbal supplements. 

In the case of Citalopram, you should avoid using it if you are also taking any of the following: heart rhythm medications, such as Class IA and III antiarrhythmics, antipsychotics, tricyclic antidepressants, certain antimicrobial agents, certain antihistamines, MAOIs (within the last two weeks), linezolid and St John’s wort (Hypericum perforatum). 

Your doctor may consider another treatment if you are taking any of the following: Sumatriptan, tramadol, lithium, tryptophan, pimozide, imipramine, desipramine, medications containing selegiline, cimetidine, mefloquine, bupropion, anticoagulants NSAIDs, metoprolol, neuroleptics and fluconazole. 

Warnings and precautions when taking SSRIs 

It’s important that you make your doctor aware of any conditions you have or are prone to before starting treatment with SSRIs, so that they can prescribe treatment safely for you. 

In the case of the SSRI Citalopram, your doctor may consider an alternative treatment if any of the following apply to you: diabetes, seizures, epilepsy, you are receiving electro-convulsive treatment (ECT), mania, panic disorder, a history of bleeding disorders, psychosis with depressive episodes, impaired kidney or liver function, heart rhythm disorders, heart problems or have recently had a heart attack.

Is it safe to take SSRIs if you are pregnant? 

If you are pregnant, think you might be pregnant, are planning on becoming pregnant during treatment, or are breastfeeding, you should tell your doctor before starting treatment. 

SSRIs have been known to cause a decrease in sperm quality in animals, which may indicate that they can cause reduced fertility in men, although this has yet to be proven in humans. 

What types of SSRIs are available? 

There are eight different types of SSRI medications available in the UK, each with a slightly different chemical makeup. This means that you may find some are easier to tolerate than others. The most commonly prescribed in the UK include: Citalopram, paroxetine, dapoxetine, sertraline, vortioxetine, escitalopram, fluvoxamine and fluoxetine.

Page last reviewed:  22/07/2020
Questions and Answers

Can SSRIs affect your ability to drive?

It’s likely that SSRI treatments will affect your ability to drive within the first few weeks of treatment. Their effects should settle down as the body becomes used to the changes in hormone levels in the body. 

It’s important to wait and see how your treatment affects you before operating any form of heavy machinery. 

Can I consume alcohol during treatment with SSRIs? 

It’s not advisable to consume alcohol during treatment with SSRIs. 

Can I buy SSRIs over the counter? 

No. SSRIs are available via prescription only. 

Can I buy SSRIs online?

You can discuss SSRI treatments and any related conditions with one of our GPhC-registered clinicians using our online video consultation service. You can book an appointment between 9.30am-4.30pm, Monday to Friday. Our clinicians can also issue fit notes and referrals to specialists for treatment, where appropriate. 


Page last reviewed:  22/07/2020

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