NEW YORK (Reuters Health) – Augmenting antipsychotic treatment with a biologically active natural product, L-theanine, improves symptoms in patients with schizophrenia or schizoaffective disorder, Israeli investigators have shown in a study reported in the Journal of Clinical Psychiatry online November 30.
Dr. Vladimir Lerner at Be’er-Sheva Mental Health Center and colleagues explain that neuroprotection has become the focus of research in psychiatric disorders associated with progressive brain tissue loss.
They note that L-theanine is an amino acid found almost exclusively in the tea plant, Camellia sinensis, typically in concentrations of 1 or 2 percent. It can pass the blood-brain barrier and its main effect is neuroprotective. Other effects are mood enhancement and relaxation
The team tested the benefits of an 8-week course of 400 mg/d L-theanine versus placebo as add-on therapy to ongoing antipsychotic treatment in 60 patients with schizophrenia or schizoaffective disorder. Forty patients completed the study.
On the Positive and Negative Syndrome Scale (PANSS), the positive subscale and the general psychopathology scores fell significantly more in the L-theanine group than the placebo group, according to the report. The effect size was modest for the positive subscale but “considerably larger” for general psychopathology.
Also, compared with placebo, L-theanine significantly reduced anxiety as measured on the Hamilton Anxiety Rating Scale (HARS), the researchers found.
“The positive results of our study may raise hopes and expectations that L-theanine may have neuroprotective ability in schizophrenia,” Dr. Lerner and colleagues write. Meanwhile, they add, “Further long-term studies of L-theanine are needed to substantiate the clinically significant benefits of L-theanine augmentation.”
J Clin Psychiatry 2010.
