What are antidepressants?

Antidepressants are medicines used to treat mental health conditions including:

• depression
• anxiety
• eating disorders
• obsessive-compulsive disorder
• post-traumatic stress disorder

Medicines are just one strategy used to treat depression and anxiety. Other treatments may also be needed, or used first. Examples include psychological treatments (talking therapy) or lifestyle changes.

How do antidepressants work?

Antidepressants are thought to work by affecting the levels of several chemicals in the brain (neurotransmitters) that influence mood and anxiety, including:

• serotonin
• noradrenaline
• dopamine
• melatonin

However, this process isn't fully understood.

Antidepressants can take some time to work, so you might need to keep taking them for a while before your symptoms improve.
If you have depression, you may begin to feel an improvement between 2 to 4 weeks after starting an antidepressant medicine. It can take up to 6 to 8 weeks to feel the full effect of treatment.

If you have an anxiety disorder, it may take 4 to 6 weeks before you start feeling better. It may take up to 12 weeks to feel the full effect of treatment.

In some people, antidepressants are not effective, no matter how long you take them. In this case, your doctor will discuss other ways to treat your mental health conditions.

What types of antidepressants might I be prescribed?

There are many different types of antidepressants. They are grouped according to how they work in the body. Within each group, there are several different medicines that work in a similar way.

• Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed antidepressant class in Australia. They are not more effective than other antidepressants, but they are usually well-tolerated by most people. This means that most people find that side effects are not too troublesome. Examples include citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine and sertraline.
• Serotonin and noradrenaline reuptake inhibitors (SNRIs) may be used for more severe or persistent depression. They include duloxetine, venlafaxine and desvenlafaxine.
• Noradrenaline reuptake inhibitors (NARIs) are less likely to cause drowsiness than other classes. This class includes reboxetine.
• Tricyclic antidepressants (TCAs) tend to have more harmful side effects than newer medicines. They are less commonly prescribed today. They include amitriptyline, nortriptyline, clomipramine, dothiepin, doxepin, imipramine and trimipramine.
• Reversible inhibitors of monoamine oxidase A (RIMAs) are more commonly used to treat anxiety than depression. They include moclobemide.
• Noradrenaline-serotonin specific antidepressants (NaSSAs) are used to treat depression and insomnia. They can cause weight gain. This class includes mirtazapine.
• MAOIs (monoamine oxidase inhibitors) are rarely prescribed today due to the chance of side effects and interactions with other medicines. They include phenelzine and tranylcypromine.
• 'Atypical' antidepressants don't fit into the classes above. They include agomelatine and vortioxetine. Agomelatine stimulates melatonin receptors, while vortioxetine works on serotonin receptors, but in a different way to SSRIs and SNRIs.

Read more on a specific antidepressant medicine by searching the name in the online healthdirect Medicines tool.

What are the side effects or risks associated with antidepressants?

Like all medicines, antidepressants may have side effects.

Side effects differ between different antidepressant medicines and classes. Some antidepressant side effects may include:

• headaches and dizziness
• nausea
• weight gain
• anxiety or restlessness
• difficulty sleeping, or excessive sleepiness
• sexual problems, such as a low sex drive

Some of these side effects improve as your body gets used to the medicine. Your doctor may change your dose to help reduce side effects. They may also suggest ways to manage these side effects.

For most people, the side effects are not severe enough that they need to stop taking the medicine.

Different people may experience different side effects. It's important to talk to your doctor about your individual situation. Some people experience no side effects at all.

It's a good idea to ask your doctor or pharmacist about any common side effects associated with the antidepressant you have been prescribed.

Suicide risk when starting antidepressants

Some people, especially children and young people, can experience an increase in self-harm and suicidal thoughts when they start taking antidepressants. These symptoms generally go away over time as the medicine starts to work.

If someone you care about is starting antidepressants, it's a good idea to look out for signs of suicidal thoughts or plans. If you are starting antidepressants yourself, think about what you can do to keep yourself safe if you start thinking about suicide.

Learn about suicide warning signs and what to do.

Serotonin toxicity

A rare side effect of some antidepressants is serotonin toxicity (also known as serotonin syndrome). This can happen when the levels of serotonin in your body are too high.

Symptoms of serotonin syndrome include:

• tremor
• poor coordination
• confusion or restlessness
• shivering, sweating or fever
• diarrhoea

If you suspect that you, or someone else, is experiencing serotonin toxicity, seek urgent medical advice or visit the emergency department of your local hospital.

Serotonin toxicity is more common if you are taking more than one antidepressant or are taking other medicines, including opioid medicines, migraine medicines or recreational drugs.

You can reduce your chance of developing serotonin syndrome by taking your medicines exactly as prescribed by your doctor and avoiding recreational drugs.

Antidepressants during pregnancy or breastfeeding

If you take antidepressants and are pregnant, planning a pregnancy or breastfeeding, it's a good idea to talk to your doctor. Some medicines are not recommended during pregnancy or breastfeeding.

Your doctor will be able to help you stop the antidepressant in a safe way, or help you switch to a type of antidepressant that is safe to take while pregnant or breastfeeding.

If you are pregnant or breastfeeding and would like to find out more about your medicines call Medicines Line on 1300 633 424.

You can also contact a local pregnancy drug information centre to find out more.

How do I know which antidepressant is right for me?

Your doctor will consider different factors when deciding which antidepressant to prescribe, including:

• your age
• your sex
• your main symptoms
• potential side effects
• potential interactions with any other medicines you are taking
• if you are pregnant or breastfeeding
• your preferences and lifestyle

You may find that one type of antidepressant is more effective than others at relieving your symptoms. It can take some time to identify which antidepressant is right for you.

It's important to talk to your doctor on a regular basis, especially when you first start taking an antidepressant. If the medicine is causing side effects, or isn't working, your doctor can advise whether another type of antidepressant might be better.

How do I take antidepressants?

Most antidepressants are taken daily. Your doctor or pharmacist may recommend that you take your medicine at a certain time of day to lower the chance of side effects. For example, you might prefer to take a medicine that can make you drowsy at night before bed.

How long you will need to take antidepressants for depends on your situation and response to treatment. Some people take antidepressants for 6 to 12 months before stopping and their symptoms do not come back. Other people need to take antidepressants for longer, sometimes for life.

Stopping antidepressants

Stopping antidepressants suddenly is likely to cause withdrawal symptoms, including:

• nausea or vomiting
• dizziness
• confusion
• anxiety or agitation
• sweating
• sleeping difficulties

The specific withdrawal effects depend on the class of medicine you have been taking, your dosage, and how long you have been taking them for.

If you want or need to stop your antidepressant medicine, make sure to ask your doctor how to taper (gradually reduce) your medicine safely. Gradually reducing the dose of medicine you take can lower the chance of you experiencing withdrawal symptoms.

If you experience withdrawal effects despite tapering your medicine, speak to your doctor. They may recommend a slower rate of tapering of your dose.

For more information on discontinuing antidepressants see 'stopping antidepressants'.

In some cases, you may wish to switch to a different type of antidepressant medicine. If your doctor recommends that you switch to a different antidepressant, ask them for specific instructions about when to taper and stop your current medicine, and when to start the new one.

When should I see my doctor?

If you are experiencing symptoms of depression or anxiety, see your doctor. They can help you identify the best strategy to relieve your symptoms.

You should also speak to your doctor if you:

• experience side effects that trouble you
• continue to experience symptoms, despite treatment
• become pregnant, are planning to become pregnant or start breastfeeding

Are there any alternatives to treat depression and anxiety?

There are many ways to help your symptoms of depression and anxiety, including:

• psychological therapies
• lifestyle changes
• medicines
• medical procedures such as electroconvulsive therapy (ECT) and transcranial magnetic stimulation (TMS)

Some people feel better with psychological therapy alone. Others find it best to use a combination of antidepressant medicines and psychological therapy.

There are many different psychological therapies. The most common is cognitive behavioural therapy. This therapy aims to identify and change your negative thoughts and how you react to them. Other types of therapy aim to get you to accept your thoughts and environment.

Lifestyle changes can also help:

• Exercise can help improve your mood and self-esteem as well as reduce the chance of weight gain (a common side effect of antidepressants).
• Stop smoking, because it can interfere with some antidepressant medicines.
• Reduce or avoid alcohol, because having alcohol can make depression worse.
• Ensure you get enough sleep — sleep deprivation can make your mood symptoms worse.
• Eat a healthy and balanced diet.
• Relaxation and meditation can help improve symptoms of depression.

Some people find that certain herbal medicines help relieve mild symptoms of depression and anxiety. Other people take herbal medicines to help with sleep.

If you choose to take herbal medicines or remedies, make sure to let your doctor know, as they might interact with medicines your doctor prescribes.

Resources and support

Asking about your treatment or medicine is important to help you understand your options. Read healthdirect's guide to important questions to ask your pharmacist or doctor before taking a medicine.

You can read more about your antidepressant medicine by reading the Consumer Medicines Information (CMI).

Call 1300 MEDICINE (1300 633 424) to speak with a pharmacist who can answer your questions about medicines.

Here are some resources about antidepressants for people with depression and their families:

• Call Beyond Blue on 1300 22 4636 or visit its website for information and support for people with depression and anxiety and their families.
• Call SANE on 1800 187 263 or visit its website for information and support for people with mental health conditions and their friends, families and communities.
• The Black Dog Institute researches mental health in Australia across the lifespan, and has resources about mental health conditions or the wider community.

Other languages

Embrace Multicultural Mental Health offers mental health resources and personal stories translated in more than 30 languages.

You can find translated information about medicines on the NPS MedicineWise website.

Information for Aboriginal and/or Torres Strait Islander people

Visit a National Aboriginal Community Controlled Health Organisation (NACCHO) for culturally safe support — find one near you.

• 13YARN — to talk with Aboriginal and/or Torres Strait Islander Crisis Support. Call 13 92 76.
• NPS MedicineWise — About Depression Medicines; Information for Aboriginal and Torres Strait Islander people.