Medications

• Certain medications both prescription based and non-prescription based can cause an overactive bladder. The most common drug interactions include diuretics and drugs containing even small amounts of caffeine.
  
  

Genetic and Acquired Disorders

• Neurological disorders, including multiple sclerosis and Parkinson's disease, can lead to an overactive bladder, as can tumors in the bladder and even cancer of the bladder. Essentially any body damage that affects the nervous system or the direct bladder region may cause an overactive bladder to be present.
  
  

Accidental Body Damage Including Infections

• Overt stress on the body, such as nerve damage caused by any type of trauma, can also cause an over active bladder, specifically if that damage occurs to the pelvis or abdominal areas. Healthy Woman points to urinary tract infections as another area which can also lead to an overactive bladder. Finally, according to MedicineNet, if the patient has been treated for incontinence in a past surgery there could be an outlet blockage at the bladder.