Parkinson's disease, marked by deterioration of nerve cells or neurons in the portion of the human brain referred to as substantia nigra, has various suspected causes. For example, doctors already know that lack of dopamine results in problems with nerve function and body movement. There is evidence that Parkinson's disease also has hereditary causes, toxicity-related causes, and oxidative stress-related causes. In addition, doctors have noted that there are conditions and medications which result in symptoms which resemble Parkinson's disease.
When the nerve cells or neurons in the substantia nigra brain area are functioning in a normal manner, the neurons produce dopamine. Dopamine enables communications between brain areas, such as from the substantia nigra to the corpus striatum. If this process goes correctly, it results in healthy, balanced, and smooth muscle movements; however, if there is an insufficient amount of dopamine, that leads to problems with nerve function and a corresponding lack of control over body movement that is associated with Parkinson's disease. Thus, lack of dopamine is one of the causes of Parkinson's.
Studies have shown that another one of the possible causes of Parkinson’s is hereditary or genetic. For instance, specific abnormalities in genes have been found. Of note, not all individuals with Parkinson’s have a gene abnormality; however, some people have a gene associated with Parkinson’s.
Certain toxins can also be causes of Parkinson’s. The toxins may be external toxins or could be internal toxins that function by destroying dopaminergic neurons in the brain. This is the manner in which the toxins cause Parkinson's disease. Specific toxins that have been implicated include pesticide, carbon monoxide, manganese, and carbon disulfide.
Oxidative stress is also one of the potential causes of Parkinson’s disease. The presence of environmental toxins results in excessive amounts of free radicals being formed inside the body. Oxidation can cause problems in parts of the body such as tissues or brain neurons and this can lead to the occurrence of Parkinson's disease.
Conditions such as atherosclerosis or stroke could cause Parkinson's-type symptoms. Shy-Drager, a degenerative health syndrome, could also cause Parkinson's-type symptoms. Alternative medicine perspectives such as the Cayce readings have described that problems at the glandular level and nervous system coordination problems can cause Parkinson's. Cayce also cited mercury poisoning, medication, and infection as being causes of Parkinson’s in some cases.
Medications can also cause Parkinson's-type symptoms. For example, anti-psychotics used in treatment of schizophrenia or paranoia can cause Parkinson's. Also, the street drug contaminant known as one-methyl-four-phenyl-one-two-three-six-tetrahydropyridine (MPTP) can cause Parkinson's-type symptoms.