Tier 2 — strong

Effect of clozapine and adjunctive high-dose glycine in treatment-resistant schizophrenia

Potkin SG, Jin Y, Bunney BG, Costa J, Gulasekaram B
The American journal of psychiatry 1999 156(1):145-147

Bibliography

PubMed
PMID 9892314
DOI
10.1176/ajp.156.1.145
Funding
Funding was not specified in the indexed abstract; the full funding disclosure has not been verified.
Competing interests
The accessible abstract does not establish the authors' competing interests; absence of a statement is not evidence of no conflicts.

Study snapshot

DesignRandomized controlled human intervention
ModelAdult humans
Sample19 clozapine-treated adults: 9 glycine and 10 placebo
InterventionAdjunctive glycine 30 g/day versus placebo with clozapine 400–1,200 mg/day
Duration12 weeks
EndpointsPositive and negative symptoms; Movement-related adverse effects

What the study showed, in plain terms

Adding glycine to clozapine did not improve symptoms in this small trial. The findings raise concern that effects of glycine differ with the accompanying antipsychotic.

Key findings

  • No benefit was detected for positive or negative symptoms.
  • The clozapine-only comparison improved positive symptoms more than the glycine combination.

What this study can and cannot tell us

Small preliminary study; it does not quantify the risk for all clozapine users.

Medication interactions cannot be inferred from low-dose healthy-volunteer studies.

Related papers in the corpus

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Buchanan RW et al. · The American journal of psychiatry · 2007
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High-dose glycine added to olanzapine and risperidone for the treatment of schizophrenia
Heresco-Levy U et al. · Biological psychiatry · 2004
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Efficacy of high-dose glycine in the treatment of enduring negative symptoms of schizophrenia
Heresco-Levy U et al. · Archives of general psychiatry · 1999
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Double-blind, placebo-controlled, crossover trial of glycine adjuvant therapy for treatment-resistant schizophrenia
Heresco-Levy U et al. · The British journal of psychiatry : the journal of mental science · 1996
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Amelioration of negative symptoms in schizophrenia by glycine
Javitt DC et al. · The American journal of psychiatry · 1994
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Adjunctive high-dose glycine in the treatment of schizophrenia
Javitt DC et al. · The international journal of neuropsychopharmacology · 2001

Editorial review

Reviewed by the Biohack Blueprint research team

Last verified

Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction