What Are the Different Types of Tremors, and What Causes Them?

What is a tremor?

A tremor is a repeated involuntary movement of some part of your body. This can happen in your hands, arms, legs, head, or even vocal cords. You have probably experienced shaky hands at some point in your life — maybe when you were hungry, feeling anxious, or had a bit too much caffeine. And this is completely normal. But there are many different types and causes of tremors, which we will go over here. 

First, tremors are divided into two main types: 

1) Action tremor

This describes a tremor that is most noticeable when you are moving part of your body and improves when you are still. There are different kinds of action tremors. One type is an intention tremor, which happens when you move part of your body purposefully to reach or aim for something. For example, if you have an action tremor, you may notice a tremor in your hand that gets worse as you reach for a pen.

2) Resting tremor

This type of tremor happens when you are still and improves when you start moving. For example, a resting tremor in your hand will go away when you start to reach for a cup. This kind of tremor can be seen in Parkinson’s disease, but it can also have other causes.

What are the different causes of tremors?

There are many different types and causes of tremors. The type of tremor you have often gives important clues into the underlying cause or diagnosis. 

Physiologic tremor

This is the most common type of tremor, and it’s completely normal. If you hold out your hand in front of you or reach for an object, you may see that your hand has a small shake. For some people, this is more visible than for others. This is an action tremor that can be worsened if you have too much caffeine, take certain medications, or are feeling stressed.

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Essential tremor

This is the second-most common kind of tremor. It is an action tremor that worsens with purposeful movement like writing. It is common and affects 10 million people in the U.S. It is not dangerous to your health but for some people can lead to difficulty doing tasks. And some are bothered by the appearance of their tremor in social situations. 

Essential tremor most often affects hands and arms on both sides of your body. It can also affect your head or vocal cords and cause difficulty speaking. You may notice that one side of your body is affected more than the other, depending on if you are right- or left-handed. 

About half the time, essential tremor runs in families, which is why it is also sometimes called familial tremor. It can start at a young age, but it also can affect adults. People with essential tremor have it their whole lives, and, for some, it may worsen as they age. Some people choose to start taking medications to decrease the tremor when it becomes bothersome to them. 

Parkinson’s disease tremor

The tremor seen in Parkinson’s disease is typically a resting tremor that gets better with purposeful movement. It may be the very first sign of this condition, but some people with Parkinson’s disease never develop a tremor. 

This tremor often begins in the fingertips and progresses over time to involve the hands or other parts of the body. It is sometimes known as a “pill-rolling” tremor because it can look like you are rolling a very small object using your thumb and forefinger. A Parkinson’s disease tremor also usually starts on one side of the body, but over time it can affect both sides. It is usually seen in adults over the age of 65, though it can develop in younger individuals.

Tremors from brain injury

Any condition that leads to damage or injury in the brain can cause a tremor. Examples include strokes, multiple sclerosis, tumors, or trauma to the brain. The kinds of tremors seen in these conditions are as varied as the causes.

Tremors from medication, substances, or toxins

Certain medications can cause a tremor, including:

• Asthma medications, such as albuterol

• Depression medications, such as selective serotonin reuptake inhibitors (SSRIs)

• Antipsychotic medications, such as lithium

• Seizure medications, such as valproate sodium

• ADHD medications, such as amphetamines

Another common cause of tremor is caffeine ingestion. Tremors caused by medications or caffeine are not dangerous and usually go away if the medication or caffeine intake is stopped.

Toxins, like mercury or lead, can also cause tremors. This cause of tremor is very uncommon and only occurs after substantial exposure to the toxin.

Withdrawal tremors 

People who drink alcohol or take benzodiazepines every day over a long period of time are at risk for withdrawal. One of the first symptoms of this is a tremor. Alcohol and benzodiazepine withdrawal can be dangerous, and, in severe cases, life-threatening. If you develop a tremor that you think is related to withdrawal, consider getting help or going to see your healthcare provider. They can help you with a plan and prescribe medications so you can do this safely.

Tremors associated with other medical conditions

Certain other medical conditions can also lead to tremor. One of the most common examples is overactive thyroid (hyperthyroidism). Your healthcare provider may check a blood test if this is suspected.

How is a tremor diagnosed?

If you notice a tremor, your healthcare provider can help. Many times, they can diagnose the tremor based on how you describe your tremor and when you notice it the most. Sometimes, your provider may refer you to a neurologist — a doctor that specializes in the nervous system — who can help make a diagnosis. 

Occasionally, your provider will recommend some testing when the cause of your tremor is unclear. Some examples of these tests are: 

• Blood tests

• Imaging studies, like an MRI, of the brain or spine

• An electromyography (EMG), which measures your muscle and nerve function

How are tremors treated?

The treatment options for tremors depend on the cause. Most tremors, like essential tremor, are not harmful to your physical health — but they may affect your day-to-day functioning. If this is the case, medications can help treat your symptoms. When a tremor is a symptom of another medical condition, like Parkinson’s disease or hyperthyroidism, the treatment is aimed at the underlying condition. 

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Written by:

Joanna Jan, MD

Joanna Jan, MD, is board-certified in internal medicine and licensed to practice medicine in the state of Pennsylvania. In 2017, she received her board certification from the American Board of Internal Medicine.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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