Some causes of tremor are multiple sclerosis, hyperthyroidism, liver failure, stroke and traumatic brain injury, says the National Institute of Neurological Disorders and Stroke. Other causes are diseases that damage the central nervous system, such as Parkinson's disease. Certain drugs that stimulate the nervous system can cause tremor.
Alcohol abuse or withdrawal can cause tremor, as can mercury poisoning, says the National Institute of Neurological Disorders and Stroke. Some causes of tremor are unknown and might be hereditary.
There are different types of tremors, claims NINDS. Essential or benign tremor mostly affects a patient's hands, though the head and other areas of the body can be involved. Essential tremor is often worsened by stress, illness, fatigue and hypoglycemia.
Tremor caused by Parkinson's disease is often the first sign that the disease is present, quotes the National Institute of Neurological Disorders and Stroke. Parkinsonian tremor is caused by a disease that damages areas in the brain that regulate movement. It presents with the classical "pill rolling" of the hands.
Dystonic tremor accompanies dystonia, a disorder in which the muscles involuntarily contract and cause parts of the body to twist or freeze into painful attitudes, claims NINDS. This type of tremor is usually eased by rest. Cerebellar tremor is caused by damage to the cerebellum through stroke or disease, or from alcoholism.