What are extrapyramidal symptoms (EPS)?

What are the main types of extrapyramidal symptoms?

Extrapyramidal symptoms are usually described as four separate effects. A person can have one of them, several at once, or none at all. Each has an everyday description and a clinical name, and knowing both makes it easier to talk to a doctor.

• Shaky hands or trembling (tremor): a shaking you can see or feel, often most noticeable when holding a cup or phone.
• Can't sit still, restless inside (akathisia): an inner restlessness with a strong urge to keep moving.
• Stiff, tight muscles (muscle rigidity): muscles that feel tight and make everyday movement more effortful.
• Slowed down, moving heavily (bradykinesia): movements that feel slower, smaller or harder to start.

When stiffness, slowness and tremor appear together, doctors often call it drug-induced parkinsonism, because it can look like Parkinson's disease even though a medicine is the cause.

Why do some medications cause movement side effects?

Many antipsychotic medications work partly by blocking dopamine, a chemical messenger in the brain. Dopamine also helps a group of brain structures called the basal ganglia coordinate smooth, controlled movement. When dopamine signalling in those movement pathways is reduced, movement side effects can appear.

Some antidepressant medications affect related brain systems as well, which is why restlessness and tremor are also reported in people taking antidepressants. Published comparisons of antipsychotic medicines show that the chance of movement side effects differs considerably from one medicine to another.

Which medications can cause extrapyramidal symptoms?

Extrapyramidal symptoms are most often linked to a few groups of medicines. Within each group, individual medicines differ, and the dose and how recently it changed matter too.

• Antipsychotic medications, both older (first-generation) and newer (second-generation) ones. On average, older antipsychotics are linked to more movement side effects, but some newer ones can cause them too.
• Some antidepressant medications, including the group known as SSRIs, which are a recognised cause of restlessness (akathisia) and tremor in some people.
• Some other medicines that block dopamine, such as certain anti-nausea medicines.

This site does not name individual medicines. Your doctor or pharmacist can tell you how the medicine you take compares, and the Consumer Medicine Information leaflet that comes with every prescription medicine in Australia lists its known side effects.

How common are extrapyramidal symptoms?

Movement side effects are among the most commonly discussed side effects of antipsychotic medication, and how often they happen depends heavily on the medicine and the dose. They are a well-known and well-studied group of side effects, and doctors expect to hear about them.

Because they can start gradually, people do not always connect them with a medicine. A slight tremor or a restlessness that is hard to put into words is easy to put down to stress or tiredness, which is one reason keeping a simple record helps.

When do extrapyramidal symptoms usually start?

Timing differs by type. Inner restlessness (akathisia) often begins within days to a few weeks of starting a medicine or increasing a dose. Stiffness, slowness and tremor usually build up more gradually, over weeks to a few months.

A change in how you feel or move soon after starting, stopping, switching or changing the dose of a medicine is useful for your doctor to know about, even if you are not sure the two are connected.

What are anticholinergic side effects?

Anticholinergic side effects come from medicines blocking acetylcholine, another chemical messenger. They are not movement symptoms, but they are common with some psychiatric medicines and are often discussed alongside EPS.

• Dry mouth
• Constipation
• Blurred vision
• Difficulty passing urine
• Feeling foggy, or finding it harder to concentrate and remember things

When several medicines with anticholinergic effects are taken together, doctors sometimes talk about the anticholinergic burden. EPSpeak's medication profiles include anticholinergic effects as one of three scores, drawn from published research.

Is it EPS, or something else?

Many things besides medication can cause shakiness, restlessness, stiffness or slowness. Anxiety, poor sleep, caffeine, alcohol, low blood sugar, thyroid problems, other health conditions and other medicines can all play a part. Low mood itself can also make movement feel slower and heavier.

Only a doctor can say whether a medicine is behind a change. What you can do is notice it, write it down, and bring it to your appointment so your doctor has something specific to work with.

What should I do if I think I have EPS?

Do not stop or change your medication on your own. Stopping suddenly can bring back the symptoms the medicine was prescribed for, or cause other effects. Instead, contact your doctor or care team and let them know what you have noticed.

• Write down what you noticed, in your own words.
• Note when it started, and whether any medicine or dose changed around that time.
• Record how often it happens, how long it lasts and what makes it better or worse.
• Describe how it affects your day, such as sleep, work, walking or sitting through a meal.
• Bring your notes to your appointment, or share your record with your clinician.

Movement side effects are well recognised, and there are usually options your doctor can talk through with you.

Other movement effects this site does not cover

Two other movement effects can be linked to these medicines: sudden muscle spasms that pull the body into a fixed position (dystonia), and involuntary movements that develop over a longer time, often in the face or mouth (tardive dyskinesia). EPSpeak's medication profiles do not cover them, so this site does not explain them in detail. If you notice either, tell your doctor.

How EPSpeak helps you keep track

EPSpeak is a medication and symptom companion for people taking antidepressant or antipsychotic medication. It lets you log your medications and doses, complete a short daily voice and wellness check-in, note movement changes in your own words, and see your history build up over days and weeks.

When you are ready, you can share your record with a clinician you choose using a QR code. EPSpeak does not diagnose anything and does not tell you what is causing a change. It gives you and your care team a clearer record to talk through.