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Acute dietary tryptophan depletion: effects on schizophrenic positive and negative symptoms.

Posted on 05/09/2010
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Because brain serotonin levels depend directly on the amounts of exogenous tryptophan (TRP) available for its synthesis, amounts of TRP in the diet may be manipulated to alter the corresponding levels of serotonin. This technique has been used for probing the role of serotonin in mediating various forms of pyschopathology.

In this study, 16 patients meeting DSM III-R criteria for schizophrenia (n = 14) or schizoaffective disorder (n = 2) were assessed for the effects of acute dietary TRP depletion under controlled conditions. The hypothesis was that lowering of serotonin would result in a diminution of 'positive' and/or 'negative' symptoms of psychotic disorders. No clinically or statistically significant improvement compared to baseline occurred when TRP depletion was imposed.

Indeed, there was a statistically significant deterioration on measures of negative symptoms. The results are discussed in the context of the methodological issues.

About the Authors

Sharma RP, Shapiro LE, Kamath SK, Soll EA, Watanabe MD, Davis JM. (1997) Acute dietary tryptophan depletion: effects on schizophrenic positive and negative symptoms. Neuropsychobiology. 1997;35(1):5-10. Psychiatric Institute, University of Illinois at Chicago, 60612, USA.

Comments

Dr_Abram_Hoffer

Posted on 05/16/2010 06:48 pm

This new work with NAD Therapy is very exciting and I think is right on target. It is indeed an energy-metabolic-deficiency (EMD) because in the absence of this coenzyme cycle almost all the reactions in the body run down... I congratulate Theo Verwey and his colleagues for this remarkable advance in using this concept and in using a simple test, the ratio of pyruvate to lactate as a diagnostic measure, to indicate the dose, duration of treatment etc.

NAD_Blood_Tests

Posted on 05/09/2010 05:43 pm

It is known that dietary tryptophan can be converted to nicotinamide nucleotides in the body. Both the level of tryptophan and the energy content of the diet have been shown to influence the efficiency of conversion. The rate at which tryptophan is converted to nicotinamide nucleotides in the body may be expected to be influenced by the activities of the enzymes concerned with the tryptophan-NAD pathway.