Health A-Z

Medical Content Created by the Faculty of the
Harvard Medical School

Essential Tremor

What Is It?

Tremor is shaky movements of your hands, limbs, head or voice that you can't control. Sometimes tremor is a normal reaction to a situation such as fear, fatigue or anger. It also can be a side effect of too much caffeine, a medication, or withdrawal from a drug or medicine. When tremor occurs during activities and there is no emotional or chemical cause, it can be a sign of a neurological disease called essential tremor.

Essential tremor is most noticeable when your body is in action, such as when you are writing, typing or pouring a beverage. This is one way essential tremor is different from Parkinson's disease, another neurological illness. The tremors of Parkinson's are more noticeable at rest. People with Parkinson's watch their hands shake when they rest in their lap, but when they reach out to grab or hold something, such as a cup of coffee, the shaking stops. Just the opposite happens in people with essential tremor. Their tremors begin when they use their hands, for example, when holding a pen or pencil. Essential tremor often begins in the dominant hand (the one used for writing).

As many as one in four people develop essential tremor as they age. You are more likely to develop essential tremor if you have a parent or sibling with the condition. People who have an elderly parent or sibling with essential tremor are five times more likely to develop tremor than people without affected relatives. If your parent or sibling had essential tremor before age 50, then you are 10 times more likely to get it than average, and it may start at an early age. Essential tremor is 20 times more common than Parkinson's disease. It is much more common in the elderly.