Monoamine Theories in Psychiatry

There are a number of monoamine theories in psychiatry. There are serotonin theories for depression (3). There is some serotonin in the brain, but most of it is in the intestines. Nevertheless the serotonin syndrome is a terrible side effect of SSRIs that can even be fatal. When serotonin gets too high, it is a disastrous situation. The main theory is that serotonin is supposed to be too low in depression.

However, many studies have used tryptophan depletion to see what happens if you lower brain serotonin (1, 2). If serotonin were in fact low in depression, this should make the patient worse. It is not clear to me why they want to make the patient worse unless it is a test of the theory.

Dopamine

Dopamine can be lowered by branched chain amino acids (4). I can see doing this in rats, but it seems too dangerous to try in humans. However, it has been tried. Certain amino acids are precursors of dopamine. These are phenyalanine and tyrosine. Lowering these amino acids can slow dopamine production.

One controversial theory in psychiatry is that a toxic metabolite of dopamine causes schizophrenia. This theory was favored by Friedhoff, van Winkle, and others. Unfortunately both Friedhoff and van Winkle are deceased. I favor this theory, which I feel is brilliant.

Tryptophan

There is yet another theory. One theory is that tryptophan produces a toxin which causes schizophrenia. This theory was favored by Gilka. At one time it was favored by Himwich and his colleagues, but Himwich is now deceased, unfortunately. This theory is based largely on the chemical structure of tryptophan, which is in the indoleamine family. It has an indole ring. LSD also has such a ring. It also has a benzene carbon ring.

Reference 9 throws cold water on serotonin theories.

Drugs

Drugs can be used to deplete catecholamines (12, 13). Since hypertension is known to be caused by too many catecholamines, catecholamine depletion is a potential therapy for hypertension. Some catecholamines raise the blood pressure. L-DOPA, on the other hand, increases catecholamines (14). It has psychiatric side effects. It has been found to make schizophrenia worse.

Nutrition

Refs. 16-19 discuss the effects of nutrition on neurotransmitters. It is a common myth that supposedly what you eat has no effect on the brain. It certainly does! Ref. 20-25 demonstrate this. Nutritional treatments for depression have been sought (26, 27).

Conclusions

Much of this material appears to support orthomolecular psychiatry (28).

References

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2. Reilly JG, McTavish SFB, Young AH. Rapid depletion of plasma tryptophan. J Psychopharmacol 1997; 11: 381-392.

3. Delgado PL, Price LH, Miller HL, Salomon RM, Aghajanian GK, Heninger GR et al. Serotonin and the neurobiology of depression. Arch Gen Psychiatry 1994; 51: 865-874.

4. Gijsman HJ, Scarna A, Harmer CJ, McTavish SB, Odontiadis J, Cowen PJ et al. A dose-finding study on the effects of branch chain amino acids on surrogate markers of brain dopamine function. Psychopharmacology (Berl) 2002; 160: 192-197.

5. Krahn LE, Lu PY, Klee G, Delgado PL, Lin SC, Zimmerman RC. Examining serotonin function: a modified technique for rapid tryptophan depletion. Neuropsychopharmacology 1996; 15: 325-328.

6. Weltzin TE, Fernstrom JD, McConaha C, Kaye WH. Acute tryptophan depletion in bulimia: effects on large neutral amino acids. Biol Psychiatry 1994; 35: 388-397.

7. Wolfe BE, Metzger ED, Jimerson DC. Comparison of the effects of amino acid mixture and placebo on plasma tryptophan to large neutral amino acid ratio. Life Sci 1995; 56: 1395-1400.

8. Lieben CKJ, Westerink B, Blokland A, Deutz NEP. Acute tryptophan and serotonin depletion using an optimized tryptophan-free protein-carbohydrate mixture in the adult rat. Neurochem Int 2004; 44: 9-16.

9. Brown CM, Fletcher PJ, Coscina DV. Acute amino acid loads that deplete brain serotonin fail to alter behavior. Pharmacol Biochem Behav 1998; 59: 115-121.

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11. Golightly KL, Lloyd JA, Hobson JE, Gallagher P, Mercer G, Young AH. Acute tryptophan depletion in schizophrenia. Psychol Med 2001; 31: 75-84.

12. Sjoerdsma A, Engelman K, Spector S. Inhibition of catecholamine synthesis in man with a-methyl-paratyrosine, an inhibitor of tyrosine hydroxylase. Lancet 1965; 2: 1092-1094.

13. Brodie HK, Murphy DL, Goodwin FK, Bunney WE. Catecholamines and mania: the effect of alpha-methyl-para -tyrosine on manic behavior and catecholamine metabolism. Clin Pharmacol Ther 1971; 12: 218-224.

14. Bunney WE, Brodie HKH, Murphy DL, Goodwin FK. Studies of alpha-methyl-para -tyrosine, L-dopa, and L-tryptophan in depression and mania. Am J Psychiatry 1971; 127: 872-881.

15. Delgado PL, Miller HL, Salomon RM, Licinio J, Heninger GR, Gelenberg AJ et al. Monoamines and the mechanism of antidepressant action: effects of catecholamine depletion on mood of patients treated with antidepressants. Psychopharmacol Bull 1993; 29: 389-396.

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17. Bottiglieri T, Laundy M, Crellin R, Toone B, Carney M, Reynolds E. Homocysteine, folate, methylation, and monoamine metabolism in depression. J Neurol Neurosurg Psychiatry 2000; 69: 228-32.

18. Lyons P, Truswell AS. Serotonin precursor influenced by type of carbohydrate meal in healthy adults. Am J Clin Nutr 1988; 47: 433-9.

19. Wurtman R, Wurtman J, Regan MM, McDermott J, Tsay R, Breu J. Effects of normal meals rich in carbohydrates or proteins on plasma tryptophan and tyrosine ratios. Am J Clin Nutr 2003; 77: 128-32.

20. Ramos M, Allen L, Haan M, Green R, Miller J. Plasma folate concentrations are associated with depressive symptoms in elderly Latina women despite folic acid fortification. Am J Clin Nutr 2004; 80: 1024-8.

21. Tolmunen T, Voutilaimen S, Hintikka J et al. Dietary folate and depressive symptoms are associated in middle-aged Finnish men. J Nutr 2003; 133: 3233-6.

22. Hintikka J, Tolmunen T, Tanskanen A, Viinamaki H. High vitamin [B.sub.12] level and good treatment outcome may be associated in major depressive disorder. BMC Psychiatry 2003; 3: 17-22.

23. Stewart J, Harrison W, Quitken F, Baker H. Low [B.sub.6] levels in depressed outpatients. Biol Psychiatry 1984; 19: 613-16.

24. Penninx L, Allen R, Stabler S. Vitamin [B.sub.12] deficiency and depression in physically disabled older women: epidemiologic evidence from Women's Health and Ageing Study. Am J Psychiatry 2000; 157: 715-21.

25. Bottiglieri T, Laundy M, Crellin R, Toone B, Carney M, Reynolds E. Homocysteine, folate, methylation and monoamine metabolism in depression. J Neurol Neurosurg Psychiatry 2000; 69: 228-32.

26. Bottiglieri T, Laundy M, Martin R et al. S-Adenosyl-L-methionine influences monoamine metabolism. Lancet 1984; 2: 224.

27. Volker, Dianne, and Jade Ng. "Depression: does nutrition have an adjunctive treatment role?." Nutrition & Dietetics: The Journal of the Dietitians Association of Australia 63.4 (Dec 2006): 213(14). Health Reference Center Academic. Gale.

28. http://www.associatedcontent.com/article/237845/the_link_between_food_allergies_and.html