L-arginine add-on Therapy in Patients With Schizophrenia

L-Arginine add-on Treatment for Schizophrenia: A Randomized, Double Blind, Placebo Controlled, Cross Over Study

This study evaluates the addition of L-Arginine to the usual regimen in the treatment of schizophrenia in adults. As a requisite of crossover design, half of the participants started with L-Arginine and the other half with placebo and switched over after a three weeks use and one week of a washout period.

L-arginine is the precursor of nitric oxide (NO), a neuromodulator of dopamine, gamma-aminobutyrate (GABA) and glutamate systems. Nitric oxide donors which increase NO levels at the cellular level could improve N-methyl-D-aspartate (NMDA) receptor dysfunction. Using L-arginine could bypass the blocked NMDA receptors and improve the therapeutic efficacy by reversing the dysfunction.

The investigators proposed that using L-Arginine, a dietary supplement in most cultures, might constitute a safe option as an add-on treatment which may display beneficial effects on positive, negative, cognitive and affective symptoms associated with schizophrenia.

Inclusion Criteria:

• Schizophrenia-Schizoaffective Disorder
• Clinical Global Impression >4
• Able to take oral medication and likely to comply the required evaluations
• On stable medication regimen for 8 weeks
• Competent and willing to give informed consent

Exclusion Criteria:

• Uncontrolled medical illness (renal disease, hepatic, cardiac diseases, gout, asthma, diabetes, sickle cell anemia, low-high blood pressure)
• History of Myocardial Infarction (MI)
• History of genital herpes infections/ receiving lysine containing treatments
• Pregnancy/ lactation
• Substance related and Addictive Disorders
• Drugs that might induce hypotension
• Intolerance to L-arginine and ingredients of placebo or L-arginine capsule