Relation of Plasma Glycine, Serine, and Homocysteine Levels to Schizophrenia Symptoms and Medication Type

• Published in: The American journal of psychiatry Vol. 162; no. 9; pp. 1738 - 1740
• Main Authors: Neeman, Guy, Blanaru, Monica, Bloch, Boaz, Kremer, Ilana, Ermilov, Marina, Javitt, Daniel C., Heresco-Levy, Uriel
• Format: Journal Article
• Language: English
• Published: Washington, DC American Psychiatric Publishing 01.09.2005; American Psychiatric Association
• Subjects: Adult; Adult and adolescent clinical studies; Amino acids; Amino Acids - blood; Amino Acids - physiology; Antipsychotic Agents - therapeutic use; Biological and medical sciences; Clozapine - therapeutic use; Female; Glycine - blood; Glycine - physiology; Homocysteine - blood; Homocysteine - physiology; Humans; Male; Medical sciences; Middle Aged; Neuropharmacology; Pharmacology. Drug treatments; Plasma; Psychiatric Status Rating Scales; Psychiatry; Psycholeptics: tranquillizer, neuroleptic; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Psychopharmacology; Psychoses; Receptors, N-Methyl-D-Aspartate - physiology; Schizophrenia; Schizophrenia - blood; Schizophrenia - diagnosis; Schizophrenia - physiopathology; Schizophrenic Psychology; Serine - blood; Serine - physiology; Human; Thiol; Psychotropic; Neuroleptic; Serine; Schizophrenia; Glycine; Sulfur containing aminoacid; Psychosis; Treatment; Homocystein; Negative symptom; Aminoacid; Neurotransmitter; Positive symptom
• ISSN: 0002-953X; 1535-7228
• DOI: 10.1176/appi.ajp.162.9.1738

OBJECTIVE: Altered glycine and homocysteine levels may contribute to N-methyl-d-aspartate receptor dysfunction in schizophrenia. The authors measured plasma levels of these amino acids in a group of patients with chronic schizophrenia and related them to the patients' symptom profiles and types of antipsychotic medication. METHOD: Plasma levels of amino acids in 94 patients with schizophrenia were compared with those in 34 age- and sex-matched normal subjects. The Positive and Negative Syndrome Scale was used to evaluate the patients' psychopathology. RESULTS: Plasma glycine levels and glycine-serine ratios were lower and homocysteine levels were higher in patients than in comparison subjects. Low glycine levels correlated with a greater number of negative symptoms. The glycine-serine ratios of normal subjects and patients being treated with clozapine did not differ significantly. CONCLUSIONS: These findings support the hypothesis that altered levels of glycine and homocysteine may coexist in patients with schizophrenia and contribute to pathophysiological aspects of this illness.