Sodium benzoate treatment not effective for early psychosis

Adjunctive use of daily sodium benzoate did not appear effective as early psychosis treatment, according to results of a randomized clinical trial published in JAMA Network Open.

“[Two] trials suggest that [sodium benzoate] may be an effective and well-tolerated adjunctive therapy for those with schizophrenia,” James G. Scott, MBBS, PhD, of QIMR Berghofer Medical Research Institute in Australia, and colleagues wrote. “However, both studies recruited participants with long-standing and/or treatment-resistant schizophrenia. Considerable recent attention has focused on optimizing treatments during the early phases of psychosis.”

Scott and colleagues sought to examine the adjunctive use of sodium benzoate for symptoms in individuals with early psychosis. They used a placebo-controlled double-masked parallel group design and enrolled 100 participants, of whom 73% were male, aged 15 to 45 years who experienced early psychosis and randomly assigned participants 1:1 to received 500 mg of sodium benzoate twice per day or placebo for 12 weeks. Key secondary efficacy measures included the Clinical Global Impression score, the Hamilton Depression Rating Scale for depression, functioning according to the clinician-rated Global Assessment of Function and the Assessment of Quality of Life Scale. The investigators also assessed PANSS subscale scores and impact on selected amino acid concentrations.

Results showed a mean baseline PANSS score of 75.3. Scott and colleagues observed no improvement in total PANSS score among sodium benzoate group vs. the placebo group. The total PANSS end result for least-square mean difference was 1.2. The researchers found no differences in any PANSS subscales, any secondary measures nor any amino acid concentrations. Between sodium benzoate and placebo groups, the sodium benzoate dose was well tolerate and had no clinically significant treatment-emergent adverse event differences.

“Future clinical trials should restrict participants to those who are treatment refractory and should further investigate whether benzoate acts by altering amino acid levels or by reducing oxidative stress in people with schizophrenia,” Scott and colleagues wrote. “In the meantime, the routine use of this agent as an adjunctive treatment for early psychosis is not recommended.”