An Introduction to Neurology

Huntington's disease has both psychiatric symtoms and neurological symptoms. It is studied by neurologists (1). Ref. 1 reported success with a low tryptophan diet in this terrible disease. The disease, named after the American Dr. Huntington, is hereditary.

Ref. 2 studied both Huntington's chorea and Alzheimer's disease. Both disorders showed increased degredation of tryptophan. One of the theories is that endogenous neurotoxins are produced from tryptophan. These endogenous neurotoxins cause neuronal death. One of these neurotoxins is quinolinic acid (3).

Neuropathology

Neuropathology is a discipline studied by neurologists and some psychiatrists. Familial basal ganglia calcification has been studied in this way. Psychiatric symptoms are seen as well as neurological symptoms. A number of basal ganglia diseases present with both neurological symptoms & psychiatric symptoms. For this reason there is a theory that schizophrenia may be a basal ganglia disease. The basal ganglia are high in dopamine.

Nutrition

"Deficiency of ubiquinone has been reported in some neurological disorders." Ravikumar A, et al (4) This substance is also called "coenzyme Q10". It can be made in the body from tyrosine. It is available as a supplement. More information on this is given in Ref. 5.
Neuropsychiatric Disorders
"The concentration of trytophan, quinolinic acid, kynurenic acid, serotonin and 5-hydroxyindoleacetic acid was found to be higher in the plasma of patients with all these disorders..." Ravikumar A, Deepadevi KV, Arun P, Manojkumar V, Kurup PA
Department of Neurology, Medical College, Trivandrum, and Metabolic Disorders Research Centre, Puliyarakonam, Trivandrum, India. (4) "There was increase in free fatty acids and decrease in albumin (factors modulating tryptophan transport) in the plasma of these patients. Concentration of digoxin, a modulator of amino acid transport, and the activity of HMG CoA reductase, which synthesizes digoxin, were higher in these patients; while RBC membrane Na+-K+ ATPase activity showed a decrease. Concentration of plasma ubiquinone (part of which is synthesised from tyrosine) and magnesium was also lower in these patients." Ravikumar A, et al (4) This appears to support orthomolecular medicine because magnesium is found in the diet, as is tyrosine. Tryptophan is also found in the diet. There is a "modulating effect of hypothalamic digoxin on amino acid transport". Amino acids are found in the diet. Various disorders were studied by the India group including primary generalized epilepsy, schizophrenia, multiple sclerosis, glioma, Parkinson's disease and syndrome-X with multiple lacunar state. None of the subjects were under medication at the time of the study. Hypercatabolism of tryptophan was seen in all these disorders. This means that too much tryptophan was being metabolized. This could be explained if too much tryptophan was entering the cells.
The result of serotonin being high directly contradicts the theories of those drug companies that make SSRI drugs. These companies favor a theory of serotonin deficiency in psychiatric disorders. The reason they favor this theory is that SSRI drugs can raise the level of serotonin.
Conclusions
Further research is needed including studies of the cerebrospinal fluid. Some such studies have already been done. The possiblity on nutritional treatments for these diseases is very real. Orthomolecular medicine is suggested. The drug L-DOPA, which is siimilar to an amino acid, is used to treat Parkinson's disease. Unfortunately psychiatric drugs have caused neurological symtoms as well as metabolic side effects. Unfortunately L-DOPA can cause psychiatric symtoms.
At one time the eccentric psychiatrist Dr. E. Fuller Torrey predicted the "death of psychiatry". He thought that neurology would take over psychiatry. However, this never happened. Another possibility is that psychiatrists could encroach on neurology. Neurology never took over psychiatry possibly bercause it didn't want to. Neurologists had their hands full with very difficult neurological diseases. They were too busy to take over psychiatry.
References

1. Med Hypotheses. 1993 Oct;41(4):325-6. Huntington's disease and low tryptophan diet. Pascoe M.

2. Adv Exp Med Biol. 1999;467:133-8. Degradation of tryptophan in neurodegenerative disorders. Widner B, Leblhuber F, Walli J, Tilz GP, Demel U, Fuchs D.

3. J Neurol Sci. 1990 Jan;95(1):29-38. The quinolinic acid hypothesis in Huntington's chorea. Bruyn RP, Stoof JC.

4. Ravikumar A, Deepadevi KV, Arun P, Manojkumar V, Kurup PA. Tryptophan and tyrosine catabolic pattern in neuropsychiatric disorders. Neurol India [serial online] 2000 [cited 2010 Jul 22];48:231. Available from: http://www.neurologyindia.com/text.asp?2000/48/3/231/1530.

5. Steen G, Axelsson H, Bowallens M : Isoprenoid biosynthesis in multiple sclerosis. Acta Neurol Scand 1985; 72 (3): 328-335.