This site became the new on June 19th. Learn more.
Show more Menu IMPORTANT: Listing of a study on this site does not reflect endorsement by the National Institutes of Health. Talk with a trusted healthcare professional before volunteering for a study. Read more... Menu IMPORTANT: Talk with a trusted healthcare professional before volunteering for a study. Read more... Menu
Give us feedback

L-arginine in Treatment as Usual in Schizophrenia

This study has been completed.
Capital Health, Canada
Information provided by (Responsible Party):
Serdar Dursun, University of Alberta Identifier:
First received: July 16, 2008
Last updated: December 9, 2013
Last verified: December 2013

STUDY OBJECTIVES: To determine whether the addition of L-arginine to treatment as usual (TAU) in schizophrenia further improves and enhances therapeutic efficacy (positive, negative and depressive symptoms) and effectiveness of antipsychotic treatment

STUDY POPULATION: Patients diagnosed (DSM-IV criteria) with schizophrenia or schizoaffective disorder

Total expected number of patients: 14

INVESTIGATIONAL COMPOUND: L-arginine capsules, 3 grams of L-arginine given twice a day (total daily dose of 6 grams/day)

DURATION OF ACTIVE TREATMENT: 3 weeks followed by wash-out phase of 5 days and 3 weeks of second treatment phase (cross-over design)

EVALUATION CRITERIA: Primary (efficacy) outcomes: PANSS scores. Secondary outcomes: Calgary Depression Scale for schizophrenia, CGI; AIMS, UKU-assessment of side-effects

ASSESSMENT SCHEDULE: Treatment arm 1: Baseline, weeks: 1,2,3, wash-out phase; week 4, cross-over phase: treatment phase-2; weeks 5,6,7

STATISTICAL CONSIDERATIONS: Analysis of variance of outcome measures with treatment as the between-subject factor and pre- and post-treatment scores as within- subjects factors.

DURATION OF STUDY PERIOD: Patient recruitment to be completed in 12 months, study full completion 18 months.

Condition Intervention
Schizophrenia Drug: L-Arginine

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Treatment
Official Title: A Randomised, Double-blind, Cross-over, Placebo Controlled, Adjunctive-treatment of L-arginine Added to Treatment-as-usual (TAU) in Schizophrenia

Resource links provided by NLM:

Further study details as provided by Serdar Dursun, University of Alberta:

Primary Outcome Measures:
  • Primary objective: To determine the efficacy of "add-on" L-arginine to treatment as usual (TAU) in schizophrenia. Primary efficacy outcome measurement is the PANSS score. [ Time Frame: 56 Days ]

Secondary Outcome Measures:
  • To determine the effects of "add-on" L-arginine treatment to TAU in schizophrenia. Secondary outcome measures are: Calgary Depression Scale for schizophrenia, CGI, AIMS and UKU-assessment of side-effects related to L-arginine treatment. [ Time Frame: 56 Days ]

Enrollment: 13
Study Start Date: September 2009
Study Completion Date: October 2012
Primary Completion Date: July 2011 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: L-arginine
Patients with diagnosis of schizophrenia will be randomised to receive L-arginine or placebo 3 grams bid (cross-over design) in addition to treatment as usual. The active treatment period will be 3 weeks, with a wash-out period of 5 days and re-commencing on the alternative arm of the randomization
Drug: L-Arginine
3 grams, twice daily, oral administration


Ages Eligible for Study:   18 Years to 65 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  1. Aged 18-65 years
  2. Diagnoses of schizophrenia or schizoaffective disorder using the Diagnostic and Statistical Manual-IV (DSM-IV) criteria
  3. Competent and willing to give informed consent
  4. Able to take oral medication and likely to complete the required evaluations.
  5. Medication remained stable 4 weeks prior to baseline.
  6. Female participants of child bearing capability must be willing to use adequate contraceptives (4.6.1a) for the duration of the study, and, willing to have a pregnancy test pretreatment and during the study.

Adequate contraception is defined as use of contraceptive double barrier system (i.e. condom and spermicide) or contraceptive implant, oral contraceptive or injected depot contraceptive plus other form of contraceptive, i.e. condom. Females will be considered incapable of child bearing if they are one year postmenopausal or irreversibly surgically sterilised.

Exclusion Criteria:

  • Relevant medical illness [serious renal, diabetes, hepatic, cardiac, low- or high-blood-pressure or other illnesses] in the opinion of the investigators. In particular, history of past or recent cardiac illness, MI and abnormal ECG and current treatments for cardiac illness. The results of the Laboratory Investigations (LFT, TFT, RFT, WBC, ECG, platelets, blood chemistry, lipids, weight/BMI) will be taken into account in determining the exclusion criteria.

    1. Relevant medical illness will be determined in the first instance by asking the patients mental health care team if the patient has any medical condition/problems. After consent has been obtained, the research nurse/research doctor will then have access to the patient's notes and if necessary communicate with his/her GP and will assess patient eligibility to take part in the clinical trial by scrutinising the patient's past medical history, most recent blood results, electrocardiograms, as well as any physical tests that have been performed on the patient. If there are any deviations from the 'norm' the investigators will assess the eligibility of the individual patient.
    2. Patients receiving active treatments for Herpes virus as L-arginine may counteract the benefits of lysine to treat herpes virus
    3. Patients who are currently receiving NSAIDs or other drugs that can cause significant stomach an gastrointestinal side-effects
    4. Drugs that alter potassium levels in the body, such as ACE inhibitors and potassium sparing diuretics
    5. Patients who are pregnant or plan to become pregnant while using this amino acid
    6. Patients who are breastfeeding
    7. Prior history of intolerance to L-arginine
    8. Any significant change of psychotropic medications done within the previous 4 weeks
    9. Diagnosis of substance abuse (except nicotine or caffeine) or dependence within the last three months according to DSM-IV criteria
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00718510

Canada, Alberta
Alberta Hospital Edmonton
Edmonton, Alberta, Canada, T5J 2J7
Sponsors and Collaborators
University of Alberta
Capital Health, Canada
Principal Investigator: Serdar Dursun, M.D., Ph.D. University of Alberta
Principal Investigator: Glen Baker, Ph.D., D.Sc. University of Alberta
Principal Investigator: John C. Lind, Ph.D. Alberta Hospital Edmonton
Principal Investigator: Phil Tibbo, F.R.C.P.C. University of Alberta
Principal Investigator: Mee-Sook Song, Ph.D. University of Alberta
Principal Investigator: Pierre Flor-Henry, F.R.C.P.C. Alberta Hospital Edmonton
Principal Investigator: Diane Cox, Ph.D. University of Alberta
  More Information

Responsible Party: Serdar Dursun, Principal Investigator, University of Alberta Identifier: NCT00718510     History of Changes
Other Study ID Numbers: CPAT7176
Study First Received: July 16, 2008
Last Updated: December 9, 2013

Additional relevant MeSH terms:
Schizophrenia Spectrum and Other Psychotic Disorders
Mental Disorders processed this record on August 18, 2017