Joshua T Kantrowitz1, Scott W Woods2, Eva Petkova3, Barbara Cornblatt4, Cheryl M Corcoran5, Huaihou Chen6, Gail Silipo7, Daniel C Javitt8. 1. Schizophrenia Research Center, Nathan Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, Columbia University, New York, NY, USA. 2. Department of Psychiatry, Yale University and Connecticut Mental Health Center, New Haven, CT, USA. 3. Schizophrenia Research Center, Nathan Kline Institute, Orangeburg, NY, USA; Department of Child and Adolescent Psychiatry, New York University School of Medicine, New York, NY, USA. 4. Department of Psychiatry, Zucker Hillside Hospital, Glen Oaks, NY, USA. 5. Department of Psychiatry, Columbia University, New York, NY, USA. 6. Department Biostatistics, University of Florida, Gainesville, FL, USA. 7. Schizophrenia Research Center, Nathan Kline Institute, Orangeburg, NY, USA. 8. Schizophrenia Research Center, Nathan Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, Columbia University, New York, NY, USA. Electronic address: javitt@nki.rfmh.org.
Abstract
BACKGROUND: Antagonists of N-methyl-D-aspartate-type glutamate receptors (NMDAR) induce symptoms that closely resemble those of schizophrenia, including negative symptoms. D-serine is a naturally occurring NMDAR modulator that reverses the effects of NMDAR antagonists in animal models of schizophrenia. D-serine effects have been assessed previously for treatment of established schizophrenia, but not in the early stages of the disorder. We aimed to assess effects of D-serine on negative symptoms in at risk individuals. METHODS: We did a double-blind, placebo-controlled, parallel-group randomised clinical trial at four academic US centres. Individuals were eligible for inclusion in the study if they were at clinical high risk of schizophrenia, aged between 13-35 years, had a total score of more than 20 on the Scale of Prodromal Symptoms (SOPS), and had an interest in participation in the clinical trial. Exclusion criteria included a history of suprathreshold psychosis symptoms (ie, no longer qualifying as prodromal) or clinical judgment that the reported symptoms from the SOPS were accounted for better by another disorder (eg, depression). Randomisation was done using a generated list with block sizes of four. Participants were stratified by site, with participants, investigators, and assessors all masked through use of identical looking placebos and centralised drug dispensation to study assignment. D-serine (60 mg/kg) was given orally in divided daily doses for 16 weeks. The primary endpoint was for negative SOPS, measured weekly for the first 6 weeks, then every 2 weeks. Participants who received at least one post-baseline assessment were included in analysis. Serum cytokine concentrations were collected at baseline, midpoint, and endpoint to assess the mechanism of action. Safety outcomes including laboratory assessments were obtained for all individuals. This trial is registered with ClinicalTrials.gov, number NCT0082620. FINDINGS: We enrolled participants between April 2, 2009, and July 23, 2012. 44 participants were randomly assigned to receive either D-serine (n=20) or placebo (n=24); 35 had assessable data (15 D-serine, 20 placebo). D-serine induced a 35·7% (SD 17·8) improvement in negative symptoms, which was significant compared with placebo (mean final SOPS negative score 7·6 [SEM 1·4] for D-serine group vs 11·3 [1·2] for placebo group; d=0·68, p=0·03). Five participants who received D-serine and nine participants who received placebo discontinued the study early because of withdrawn consent or loss to follow-up (n=8), conversion to psychosis (n=2), laboratory-confirmed adverse events (n=2), or protocol deviations (n=2). INTERPRETATION: This study supports use of NMDAR-based interventions, such as D-serine, for treatment of prodromal symptoms of schizophrenia. On the basis of observed effect sizes, future studies with sample sizes of about 40 per treatment group would be needed for confirmation of beneficial effects on symptoms and NMDAR-related inflammatory changes. Long-term studies are needed to assess effects on psychosis conversion in individuals at clinical high risk of schizophrenia. FUNDING: National Institutes of Health.
RCT Entities:
BACKGROUND: Antagonists of N-methyl-D-aspartate-type glutamate receptors (NMDAR) induce symptoms that closely resemble those of schizophrenia, including negative symptoms. D-serine is a naturally occurring NMDAR modulator that reverses the effects of NMDAR antagonists in animal models of schizophrenia. D-serine effects have been assessed previously for treatment of established schizophrenia, but not in the early stages of the disorder. We aimed to assess effects of D-serine on negative symptoms in at risk individuals. METHODS: We did a double-blind, placebo-controlled, parallel-group randomised clinical trial at four academic US centres. Individuals were eligible for inclusion in the study if they were at clinical high risk of schizophrenia, aged between 13-35 years, had a total score of more than 20 on the Scale of Prodromal Symptoms (SOPS), and had an interest in participation in the clinical trial. Exclusion criteria included a history of suprathreshold psychosis symptoms (ie, no longer qualifying as prodromal) or clinical judgment that the reported symptoms from the SOPS were accounted for better by another disorder (eg, depression). Randomisation was done using a generated list with block sizes of four. Participants were stratified by site, with participants, investigators, and assessors all masked through use of identical looking placebos and centralised drug dispensation to study assignment. D-serine (60 mg/kg) was given orally in divided daily doses for 16 weeks. The primary endpoint was for negative SOPS, measured weekly for the first 6 weeks, then every 2 weeks. Participants who received at least one post-baseline assessment were included in analysis. Serum cytokine concentrations were collected at baseline, midpoint, and endpoint to assess the mechanism of action. Safety outcomes including laboratory assessments were obtained for all individuals. This trial is registered with ClinicalTrials.gov, number NCT0082620. FINDINGS: We enrolled participants between April 2, 2009, and July 23, 2012. 44 participants were randomly assigned to receive either D-serine (n=20) or placebo (n=24); 35 had assessable data (15 D-serine, 20 placebo). D-serine induced a 35·7% (SD 17·8) improvement in negative symptoms, which was significant compared with placebo (mean final SOPS negative score 7·6 [SEM 1·4] for D-serine group vs 11·3 [1·2] for placebo group; d=0·68, p=0·03). Five participants who received D-serine and nine participants who received placebo discontinued the study early because of withdrawn consent or loss to follow-up (n=8), conversion to psychosis (n=2), laboratory-confirmed adverse events (n=2), or protocol deviations (n=2). INTERPRETATION: This study supports use of NMDAR-based interventions, such as D-serine, for treatment of prodromal symptoms of schizophrenia. On the basis of observed effect sizes, future studies with sample sizes of about 40 per treatment group would be needed for confirmation of beneficial effects on symptoms and NMDAR-related inflammatory changes. Long-term studies are needed to assess effects on psychosis conversion in individuals at clinical high risk of schizophrenia. FUNDING: National Institutes of Health.
Authors: Cathy Davies; Andrea Cipriani; John P A Ioannidis; Joaquim Radua; Daniel Stahl; Umberto Provenzani; Philip McGuire; Paolo Fusar-Poli Journal: World Psychiatry Date: 2018-06 Impact factor: 49.548
Authors: Mark J Millan; Annie Andrieux; George Bartzokis; Kristin Cadenhead; Paola Dazzan; Paolo Fusar-Poli; Jürgen Gallinat; Jay Giedd; Dennis R Grayson; Markus Heinrichs; René Kahn; Marie-Odile Krebs; Marion Leboyer; David Lewis; Oscar Marin; Philippe Marin; Andreas Meyer-Lindenberg; Patrick McGorry; Philip McGuire; Michael J Owen; Paul Patterson; Akira Sawa; Michael Spedding; Peter Uhlhaas; Flora Vaccarino; Claes Wahlestedt; Daniel Weinberger Journal: Nat Rev Drug Discov Date: 2016-03-04 Impact factor: 84.694