L-arginine in Treatment as Usual in Schizophrenia

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.