According to Kenyon College, a biological disorder is defined as the disturbance of a normal life process. The use of the term "biological" may also indicate that the disturbance is genetically obtained.
Biological disorders may be caused by outside factors, internal genetic deficiencies or a combination of both.
Biological disorders that are typically brought about by outside factors include insomnia or depression brought on by stress, and delirium due to drug overdose. Other biological disorders are commonly associated with genetic disposition, meaning that a person has a natural predisposition at birth. Examples of genetic-based biological disorders are schizophrenia, bi-polarism, dementia and attention deficit disorder.