Antidepressants faqs

Sony Rai, registered pharmacist in our 24/7 health support team

What to know before starting antidepressants

25 June 2025

Depression is a common condition that can manifest in various ways, primarily characterised by a low mood and a loss of interest in activities that once brought joy. While most experience periods of feeling down for different reasons, it becomes a concern when this feeling persists long-term and negatively impacts overall wellbeing, potentially becoming debilitating.

The severity of depression can range from mild-to-moderate-to-severe, and treatment options will be based on this severity. Healthcare professionals often promote lifestyle changes first, if feasible, such as incorporating daily physical activity, eating a balanced diet, and ensuring adequate sleep.

Non-medicinal approaches, such as talking therapies or group activities led by trained healthcare professionals, may also be beneficial. However, if these approaches have been trialled with limited success or if symptoms are moderate or severe, then medication (antidepressants) may be considered.

It’s important to remember that depression is a medical condition, and, as with all medical conditions, sometimes the help of medication is required.

Starting medication for depression can be daunting for many individuals, as it often comes with a range of concerns and uncertainties. Sony Rai, registered pharmacist in our 24/7 health support team, for members, explores some commonly asked questions and concerns around starting antidepressants.

Once I start antidepressants, will I have to be on them forever?

The duration of antidepressants use is different for everyone. Your prescriber will review your symptoms and medications regularly, and if it’s deemed unnecessary in the future, the medication can be stopped, gradually and in a controlled way. It doesn’t have to be a lifelong requirement.

Will antidepressants change my personality?

Antidepressants are designed to restore the balance of neurotransmitters (chemical messengers in the brain that help send signals between nerve cells) such as serotonin and norepinephrine. These play crucial roles in regulating mood and emotion.

Many individuals with depression may experience an imbalance of these chemicals. While these medications can help alleviate symptoms of depression, they don’t change your core personality.

Additionally, since these medications don’t address the underlying causes of depression, it’s important to consider a combination of medication and talking therapy in many cases.

What types of antidepressants are available?

There are several major classes of antidepressant drugs, as well as some that can’t be categorised into specific classes.

The most widely used class is called selective serotonin reuptake inhibitors (SSRIs). These are generally the first choice as they are well tolerated and have a good safety profile. Examples include:

  • citalopram,
  • fluoxetine,
  • and sertraline, among others.

In addition to SSRIs, other classes of antidepressant include:

  • Serotonin and noradrenaline reuptake inhibitors (SNRIs) – Duloxetine and Venlafaxine.
  • Noradrenaline and specific serotonergic antidepressants (NASSAs) – Mirtazapine.
  • Tricyclic antidepressants (TCAs) – Amitriptyline, Clomipramine and Dosulepin.
  • Serotonin antagonist and reuptake inhibitors (SARIs) – Trazadone.
  • Monoamine Oxidase Inhibitors (MAOIs) – Phenelzine, Tranylcypromine and Isocarboxazid.1

While SSRIs are often considered the gold standard in antidepressant treatment, some individuals may respond better to other classes, making the process somewhat of a trial and error.

Side effects can also prompt changes in medication, for instance, NASSAs are associated with fewer sexual side effects compared to SSRIs. TCAs are typically reserved for cases of severe depression and may be suitable for individuals with multiple conditions, such as pain or insomnia.

However, since TCAs are older antidepressants, they aren’t commonly prescribed solely for depression due to their potential for unpleasant side effects and increased risk in overdose situations. They also must be used in caution with individuals with cardiac conditions.

MAOIs, another class of older antidepressants, are used very rarely today because they require strict dietary restrictions to avoid serious interactions and side effects.1

How do antidepressants work?

In essence, SSRIs work by blocking the reabsorption of serotonin. This means that more serotonin is available to send signals between nerve cells, which can help lift your mood.

Each class of antidepressants has a unique mechanism of action, but fundamentally, they all aim to increase the levels of neurotransmitters available that are available to send messages between nerve cells.

Although depression is not caused by low levels of neurotransmitters, by enhancing the availability of neurotransmitters, such as serotonin, norepinephrine, and others, these medications work to improve mood and alleviate symptoms of depression.

What if antidepressants don’t work for me?

Currently, the choice of antidepressants for most people isn’t tailored to individual genetics. As a result, selecting medications, whether from the same class or different classes, often involves a process of trial and error.

Your prescriber will consider patient preferences and medical history, but with the many available options and varying dosages, it can take time for individuals to find the most effective medication at the right dose for them.

Will I feel better right away?

Everyone will have different responses to the medication. Some individuals may feel improvements almost immediately after taking their first dose (placebo effect), while others might experience a worsening of symptoms before they start to feel better.

During the initial few weeks, there is a possibility of:

  • increased agitation,
  • anxiety,
  • disruption or promotion of sleep (depending on the type of medication given),2
  • a small increased risk of suicidal thoughts3,

as the body adjusts to changes in neurotransmitter levels.

It’s crucial to have regular check-ins with your prescriber during this initial period, typically every one to two weeks, to discuss any concerns and ensure that an appropriate treatment plan is in place.

While some benefits of antidepressants may be noticeable within one to two weeks, it can take up to four weeks (or six weeks in elderly) to experience their full effects.

Therefore, patience is important during this time. Your prescriber will evaluate your progress and decide if any adjustments to your dosage or medication are necessary.

>Read more on what to expect when you start taking antidepressants

The best thing you can do if you’re struggling is reach out and seek help from your GP, where you can discuss your symptoms and what you’re experiencing. If this feels overwhelming to do alone, seek support from a friend or loved one, who can go with you and offer some guidance.

Further reading

References

  1. Overview – Antidepressants – NHS
  2. Effects of Antidepressants on Sleep – National Library of Medicine
  3. Do SSRIs or antidepressants in general increase suicidality? – National Library of Medicine