What is the cause for hand tremors?

See below. 1. Essential tremors or parkinson's disease or diseases of cerebellum or certain drugs like asthma inhalers, depakote, and some others.
Many causes. Hand tremors can have multiple causes. Genetic or "familial" tremors are, by far, one of the most common. Degenerative or metabolic neurological conditions along with medication side effects make up the vast majority of the other causes. Since tremors vary in their frequency (the speed of the tremor), their direction, their severity, and their course, a neurologist should perform an evaluation.