Antidepressants for depression: types, uses and side effects

Depression is a complex mental health condition that can affect mood, energy, sleep, concentration, appetite, self-esteem and overall quality of life. For many people, alongside talking therapies and lifestyle support, medication in the form of antidepressants can play a vital role.

In this article, we explain what antidepressants are, the different types, when they may be prescribed, and what to know about possible benefits and side effects. Contact us today if you need support for depression.

What are antidepressants — and how do they help?

Antidepressants are a class of medications designed to alter brain chemistry, often by affecting neurotransmitters associated with mood regulation, to help relieve symptoms of depression and improve emotional wellbeing.

They are not a “cure” in themselves, but can help reduce the severity of depressive symptoms, restore interest in daily life, improve energy and motivation, and support engagement in therapy or other recovery strategies.

Whether to prescribe an antidepressant depends on several factors, including the severity of depression (mild, moderate, severe), previous history of mental health episodes, personal preference, and response to other interventions.

Main types of antidepressants

There are several classes of antidepressants. Which one is chosen depends on the individual’s symptoms, medical history, possible interactions, and side-effect profile.

Selective serotonin reuptake inhibitors (SSRIs)

• These are among the most commonly prescribed antidepressants and are often first-line due to relatively favourable tolerability. (nhs.uk)

• SSRIs increase serotonin levels in the brain, which can help improve mood, anxiety, sleep, and appetite regulation. Typical medications in this group include those commonly prescribed for depression and some anxiety disorders.

Serotonin–noradrenaline reuptake inhibitors (SNRIs) and other newer antidepressants

• SNRIs work on both serotonin and noradrenaline systems, which may benefit people whose depression includes low energy, lack of motivation or chronic pain components. (National Library of Medicine)

• Other modern antidepressants may affect multiple neurotransmitter systems or have slightly different mechanisms — selection depends on symptoms and individual factors.

Tricyclic antidepressants (TCAs) and older medications

• TCAs are an older class, less commonly used as first-line now because they tend to have more side effects and less favourable safety profile compared with newer drugs. (HSE)

• They may still be considered in certain cases, e.g., when newer medications are ineffective or if there are specific symptom patterns.

When are antidepressants usually prescribed for depression

Antidepressants may be recommended when:

• Depression is moderate to severe, significantly impacting daily functioning or quality of life.

• Previous treatments (therapy, lifestyle, social support) have not led to sufficient improvement or aren’t feasible on their own.

• There is a recurrence of depressive episodes or ongoing risk factors that make longer-term treatment more appropriate.

Treatment should always involve shared decision-making: the patient and clinician discuss benefits and risks, consider the person's preferences and medical history, and agree on a treatment plan.

Once started, antidepressants are usually reviewed regularly. In many cases, they are continued for at least 6 months after symptom improvement; for recurrent depression, longer-term use may be considered. (NHS) Specialist Pharmacy Service

What to expect — benefits and timeline

• Some people begin to notice improvements (better mood, sleep, energy, interest) within 2–4 weeks, though full effect often takes longer.

• Medication can make therapy, daily activities and recovery more manageable by stabilising mood enough that other treatments (talking therapy, lifestyle changes) become more effective.

• Antidepressants may help reduce relapse risk when depression has recurred, when psychosocial factors remain, or when stressors continue.

Possible side effects and risks

Because antidepressants affect brain chemistry, they can produce side effects, which vary depending on the class of medication and the individual. Most are mild and may ease over time; some persist or require changing medication.

Common side effects include:

• Nausea, digestive problems, dry mouth, dizziness

• Sleep disturbances (insomnia or drowsiness), fatigue

• Headaches, blurred vision, sweating changes

• Changes in appetite or weight, weight gain or loss

• Sexual side effects (reduced libido, erectile difficulties, difficulty achieving orgasm) — especially with SSRIs.

Less common but more serious risks (which need monitoring) may include:

• Emotional changes: irritability, increased anxiety, mood changes, in rare cases activation of suicidal thoughts or behaviour, especially earlier in treatment or in younger people. (GOV)

• Withdrawal or discontinuation symptoms if medication is stopped too quickly — so tapering under supervision is often recommended.

• Rare physiological effects: changes to sodium levels or other side effects depending on the drug class and the person’s health history.

Because of varying responses, it's common for prescribers to start with an SSRI and, if side effects are problematic or symptoms persist, adjust the dose or switch to a different class or medication.

How antidepressants fit into a broader care plan

Medication alone is rarely the full answer. Best practice combines antidepressants with:

• Psychological therapies (talking therapy, CBT, trauma-informed therapy)

• Lifestyle changes: regular exercise, healthy sleep, balanced nutrition, social connection

• Monitoring and review: regular check-ins with GP or mental health professional, especially when starting, adjusting or stopping medication

• Person-centred planning: considering patient preferences, history, comorbidities, and risk factors

At Schoen Clinic Chelsea, this holistic approach can be tailored to the individual, blending medication, psychotherapy, and supportive care in a confidential, flexible setting.

Practical advice if you or someone you know is prescribed antidepressants

• Ask your prescriber what to expect: likely benefits, possible side effects, average timeline for improvement

• Keep a simple log or diary for the first weeks: mood, sleep, appetite, side effects — this helps with follow-up reviews

• Never stop or change dose suddenly without consulting a clinician — gradual tapering may be needed to avoid withdrawal effects

• Combine medication with therapy and healthy habits — antidepressants are most effective when part of a wider recovery plan

• If you experience serious side effects (e.g., severe mood changes, suicidal thoughts, physical symptoms), contact a GP or mental health professional immediately

Antidepressants: useful tools, not magic bullets

Antidepressants for depression can be effective, evidence-based tools to help relieve symptoms, improve mood, and support recovery. They are most helpful when used as part of a broader, tailored treatment plan, ideally combining medication, therapy, lifestyle support, and regular review.

They are not a quick fix, and their benefits must be weighed against possible side effects. A thoughtful, shared decision-making process between patient and clinician is vital.

If you or someone you know is considering antidepressants, or is already on them and has questions, a professional mental health clinic, such as Schoen Clinic Chelsea, can offer assessment, guidance, monitoring and support every step of the way.

Written by the Schoen Clinic UK Editorial Team, drawing on expertise from our clinicians to provide accurate and up-to-date mental health information.