The medical term you’re most likely looking for is akathisia, a neuropsychiatric condition that creates an overwhelming inner restlessness and a compulsion to keep moving. The name comes from the Greek word “akathemi,” meaning “inability to sit.” But akathisia isn’t the only possibility. Depending on what the movement looks like, when it happens, and what’s driving it, the answer could also be restless legs syndrome, psychomotor agitation, or tardive dyskinesia.
Akathisia: The Inner Urge to Keep Moving
Akathisia is the condition most people are describing when they say they physically cannot stop moving, especially in their legs. What makes it distinct is that the restlessness starts on the inside. You feel a deep, uncomfortable tension or unease that only gets better when you move. The movements themselves, the leg crossing, foot tapping, weight shifting, pacing, are a response to that internal sensation, not something that happens on its own.
People with akathisia describe it in different ways: “restless,” “tense,” “must move,” “can’t sit still,” or “can no longer concentrate.” Some also feel irritable or deeply uneasy in a way that’s hard to put into words. When sitting, the signs often include repeatedly crossing and uncrossing legs, wobbling or kicking the feet, or rotating the ankles back and forth. When standing, you might pace in place, shift your weight from one leg to the other, or repeatedly flex your calf muscles.
The condition is frequently misdiagnosed as anxiety, agitation, mania, or ADHD because the symptoms overlap so much. Two straightforward screening questions can help distinguish it: “Do you feel restless inside?” and “Is it difficult for you to sit still?” If the answer to both is yes, and the restlessness feels like it originates from within your body rather than from worry or racing thoughts, akathisia is a strong possibility.
What Causes Akathisia
The most common cause is medication. Akathisia is a well-documented side effect of drugs that block dopamine receptors in the brain, particularly antipsychotic medications. Among older (first-generation) antipsychotics, 20% to 52% of patients develop akathisia. Newer (second-generation) antipsychotics carry a lower but still significant risk, affecting roughly 10% to 20% of patients.
Antipsychotics aren’t the only culprits. Antidepressants (especially SSRIs), mood stabilizers, anti-nausea medications like metoclopramide, lithium, and even some anti-seizure drugs can trigger it. Metoclopramide, commonly prescribed for nausea and gastroparesis, causes movement-related side effects in 4% to 25% of patients. The risk is highest in the first days to weeks after starting a new medication or increasing a dose.
If you suspect a medication is making you unable to sit still, don’t stop it abruptly. The usual approach involves lowering the dose, switching to a different medication, or adding a treatment specifically for the restlessness. A type of blood pressure medication (a beta blocker) taken at low doses is one of the more commonly used options and can provide noticeable relief.
Restless Legs Syndrome
Restless legs syndrome (RLS) shares some features with akathisia but follows a very specific pattern. You feel an urge to move your legs, usually accompanied by uncomfortable sensations like crawling, pulling, or aching deep in the limbs. Four characteristics define it: the urge begins or worsens during rest or inactivity, movement partially or fully relieves it (but only as long as you keep moving), symptoms are worse in the evening or at night, and the sensations aren’t better explained by another condition.
The key distinction from akathisia is timing. RLS is strongly tied to the body’s circadian rhythm, peaking at night and often disrupting sleep. Akathisia tends to be more constant throughout the day. RLS also isn’t typically caused by medications (though some drugs can worsen it) and is instead linked to iron levels in the brain and genetics. About 5% to 10% of adults experience RLS to some degree.
Psychomotor Agitation
Psychomotor agitation is a broader term for a state of physical restlessness driven by mental distress. It shows up as pacing, hand-wringing, fidgeting, inability to sit, pulling at clothes or skin, or rapid, pressured speech. Unlike akathisia, it’s not primarily a movement disorder. It’s a feature of an underlying psychiatric condition.
This kind of restlessness is most commonly associated with bipolar disorder (during manic or mixed episodes), schizophrenia spectrum disorders, and agitated depression, a form of depression where instead of slowing down and withdrawing, you feel wired and unable to be still. It can also appear during severe anxiety, personality disorders, or as a reaction to traumatic events. Psychomotor agitation can escalate unpredictably, which is one reason clinicians take it seriously as a warning sign.
Tardive Dyskinesia
Tardive dyskinesia (TD) is another movement disorder caused by medications, but it looks and feels quite different from akathisia. The movements in TD are involuntary and repetitive, often affecting the face and mouth first: lip smacking, tongue thrusting, jaw clenching, or grimacing. It can also involve the limbs with slow, writhing movements.
The critical difference is that akathisia involves voluntary movements driven by an inner urge (you move because you feel like you have to), while tardive dyskinesia involves truly involuntary movements (they happen without your intention or control). TD also develops later, typically after months or years of medication use, whereas akathisia tends to appear within days to weeks. Both conditions can occur in the same person at the same time, which is part of why they’re sometimes confused.
How These Conditions Are Told Apart
Because these conditions overlap, doctors often use structured assessment tools. For akathisia, the most widely used is the Barnes Akathisia Rating Scale, which scores three components separately: the visible restless movements a clinician can observe, the patient’s own awareness of inner restlessness, and the level of distress the restlessness causes. A global severity rating ties them together. This matters because some people have intense inner restlessness with minimal visible movement, while others show obvious fidgeting without reporting much internal discomfort.
The location of movement helps narrow things down as well. Akathisia concentrates in the legs and lower body. Tardive dyskinesia typically starts in the face and mouth. Restless legs syndrome is confined to the legs and sometimes the arms. Psychomotor agitation tends to involve the whole body, including the hands, voice, and general posture.
Less Common Causes of Constant Movement
A few other conditions can produce an inability to stop moving. Chorea refers to rapid, irregular, and unpredictable movements that flow from one body part to another, seen in conditions like Huntington’s disease. Myoclonus involves sudden, brief muscle jerks and can be caused by certain antidepressants, antipsychotics, or mood stabilizers. Stimulant medications (prescribed for ADHD or used recreationally) can also cause restlessness and repetitive movements, though this usually resolves when the drug wears off.
Thyroid overactivity, high caffeine intake, and withdrawal from alcohol or sedatives can all produce a physical restlessness that makes staying still feel impossible. These causes are usually identifiable through blood tests or by reviewing recent changes in substance use.