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.