"Extrapyramidal symptoms" (EPS) is the umbrella term for the movement-related side effects of antipsychotic medication. They're caused by the dopamine receptor blockade in brain regions that control movement (the basal ganglia). EPS is one of the main reasons people stop their antipsychotics — but each type has its own warning signs and effective treatments.
1. Acute dystonia — sudden muscle contractions, usually in the first days
2. Akathisia — inner restlessness, usually first weeks
3. Drug-induced parkinsonism — stiffness and slowness, weeks to months
4. Tardive dyskinesia — involuntary movements, months to years
1. Acute dystonia
What it is: Sudden, sustained muscle contractions. The muscles lock in an abnormal position. Most commonly affects:
- Neck (torticollis) — head pulled to one side
- Eyes (oculogyric crisis) — eyes rolled upward and stuck
- Jaw — locked open or closed
- Tongue — protruding or twisted
It can be terrifying for the patient and family but is generally not dangerous. Usually occurs in the first 1–5 days after starting an antipsychotic or after a dose increase. More common in young men and with first-generation antipsychotics (haloperidol).
Treatment: Anticholinergic medication (benztropine 1–2 mg IM, or diphenhydramine 25–50 mg IM) reverses it within minutes. After acute treatment, an oral anticholinergic is usually prescribed for a few weeks.
2. Akathisia
What it is: An intense inner restlessness — feeling unable to sit still, needing to keep moving. The classic sign is constant pacing, foot tapping, or shifting from foot to foot. Easy to misread as anxiety, agitation, or even worsening psychosis.
Akathisia is one of the most distressing side effects and a major driver of medication discontinuation. Untreated, it has been associated with increased suicide risk. Take it seriously and report it.
When it happens: Usually within the first weeks of treatment or after a dose increase. Most common with high-potency first-generation antipsychotics, but also frequent with risperidone, aripiprazole, and lurasidone.
Treatment:
- Lower the dose — first line
- Beta-blockers — propranolol 20–40 mg three times daily works well
- Benzodiazepines — short-term relief, e.g., lorazepam 0.5–1 mg
- Mirtazapine — small doses (15 mg) sometimes help
- Switch antipsychotic — if persistent, switch to one with lower akathisia profile (quetiapine, clozapine)
3. Drug-induced parkinsonism
What it looks like: Same features as Parkinson's disease — bradykinesia (slowness), rigidity, tremor, mask-like face, shuffling gait, micrographia (small handwriting). Onset is usually over weeks to a few months on the antipsychotic.
Why it happens: The antipsychotic blocks dopamine in the basal ganglia, mimicking the dopamine deficiency of Parkinson's disease. Reversible if the offending medication is reduced or stopped.
Treatment:
- Lower the dose
- Anticholinergics — benztropine, trihexyphenidyl. Often help, but can cause cognitive side effects, especially in older patients
- Amantadine — useful when anticholinergics aren't tolerated
- Switch antipsychotic — to one with lower D2 affinity (clozapine, quetiapine)
4. Tardive dyskinesia (TD)
Covered in detail in our TD guide. The short version: involuntary, repetitive movements (often of the face, mouth, tongue, fingers, toes) that develop after months to years of antipsychotic treatment. Can persist or become permanent. Risk is lower with second-generation antipsychotics but real.
Treatment: VMAT2 inhibitors (valbenazine, deutetrabenazine) are the new evidence-based treatment.
Other related movement side effects
Neuroleptic Malignant Syndrome (NMS)
Rare but life-threatening. Triad of high fever, severe muscle rigidity ("lead pipe"), and altered mental status, plus autonomic instability (high or unstable blood pressure and heart rate). Requires emergency care and immediate discontinuation of the antipsychotic.
Which antipsychotics cause the most EPS?
From highest to lowest EPS risk (rough ordering):
- Highest: Haloperidol, fluphenazine, perphenazine
- Moderate-high: Risperidone (especially >6 mg), paliperidone, lurasidone
- Moderate: Aripiprazole, brexpiprazole (especially akathisia)
- Low: Olanzapine, asenapine
- Lowest: Clozapine, quetiapine
What to do
- Tell your prescriber about any new movement, restlessness, or stiffness
- Never stop the antipsychotic on your own — sudden stops can trigger psychotic relapse and sometimes withdrawal dyskinesia
- Annual screening with the AIMS scale for any patient on long-term antipsychotic treatment
- Use the lowest effective dose
- Consider lower-EPS alternatives if symptoms are persistent
This article is for educational purposes only and is not medical advice. Always consult your prescribing clinician for personalised guidance.