Cause

• According to FamilyDoctor.org, depression may be caused by genetics, environment or an imbalance of neurotransmitters. Tremors may be inherited or may result from a disease such as Parkinson's disease or multiple sclerosis.
  
  

Treatment

• Essential tremors, which may be hereditary, are typically treated with the drug propranolol, or with a benzodiazepine drug. Tremors due to Parkinson's disease may be managed with anti-cholinergic drugs.
  
  

Types

• Propranolol, which lowers the heart rate, is prescribed for cardiac conditions, and benzodiazepines are used to treat forms of anxiety disorder. Anti-cholinergic drugs are used to treat dementia.
  
  

Antidepressants

• According to the National Institute of Mental Health, the most popular type of antidepressant is the selective serotonin reuptake inhibitor (SSRI).
  
  

Side Effects

• Hand tremors and muscle twitching may be possible side effects of antidepressants, according to FamilyDoctor.org. MindDisorders.com states that depression may be a side effect of propranolol.