Commonly Used Food Preservative Enhances Schizophrenia Treatment

Sodium benzoate, when used as an add-on treatment was effective in those who are resistant to a drug widely used for schizophrenia.

Highlights:

Sodium benzoate, a food preservative, improves symptoms in patients who are resistant to clozapine.
Clozapine is the last-line antipsychotic agent for patients with refractory schizophrenia. But nearly 40-70% of patients do not respond to the drug.
Sodium benzoate, which has been shown to enhance other antipsychotic drugs, works in clozapine-resistant patients.

Sodium benzoate, a common food preservative improves symptoms in clozapine-resistant schizophrenia patients, according to a new study published in Biological Psychiatry.

Adding on sodium benzoate to the antipsychotic clozapine improved symptoms in patients who did not see results with any other medications. This provides a new option for the hardest-to-treat patients.

About Schizophrenia
Schizophrenia is a mental disorder characterized by symptoms of thought, behavior and social problems.

‘Sodium benzoate improved negative symptoms, such as lack of emotion and motivation in those with schizophrenia.’

"Clozapine is considered the last-line antipsychotic agent for patients with refractory schizophrenia," said Hsien-Yuan Lane, of China Medical University, referring to patients whose symptoms do not respond to available antipsychotics.

But an estimated 40-70 percent of patients with refractory schizophrenia fail to improve even with clozapine, referred to as "clozapine-resistant", exhausting all potential options for treatment.

The new study is the first to demonstrate that sodium benzoate--which has been shown to enhance other antipsychotic drugs--works in clozapine-resistant patients.

Mind-wandering - Causes, Symptoms, Diagnosis,Treatment & Prevention
Mind wandering is a spontaneous and unintentional shifting of attention of thoughts from a primary task that can happen in varying degrees.

"If the finding can be confirmed, this approach may bring hope for treating patients with the most refractory schizophrenia," said Dr. Lane.

Effects of Sodium Benzoate

Schizoaffective Disorder - Causes, Symptoms, Diagnosis, Treatment & Prevention
Schizoaffective disorder is a serious mental disorder in which the individual reflects symptoms that occur both in schizophrenia and mood disorder.

The 60 patients with schizophrenia included in the study were all taking clozapine and received a placebo or sodium benzoate as an add-on treatment for six weeks. First author Chieh-Hsin Lin, M.D., Ph.D., of Chang Gung University College of Medicine, Taiwan, and colleagues tested two different doses of sodium benzoate (1 or 2 grams per day) to find which offered the biggest impact on symptoms with minimal side effects.

Compared with the placebo, sodium benzoate improved negative symptoms, such as lack of emotion and motivation, which have a greater influence on a patient's functional outcome than the more prominent psychotic symptoms. The higher dose of sodium benzoate also improved ratings of overall symptoms and quality of life.

Psychotic Disorders Linked To Falling IQ Scores in Childhood
Falling IQ scores in childhood could indicate the risk of psychotic disorders later in adulthood.

Although sodium benzoate has improved cognitive function when combined with other antipsychotics in previous studies, the add-on treatment had no influence on cognitive function in this study--in the paper, Dr. Lin and colleagues suggest that a higher dose or longer duration of treatment may be needed for these effects. Importantly, the patients taking sodium benzoate had no side effects, confirming the treatment is safe to use at the doses tested.

Sodium benzoate works by preventing the breakdown of D-serine, a brain chemical that plays an important role in signaling that is disrupted in the brains of people with schizophrenia.

"Receptors for D-serine are long-standing targets for medication development in schizophrenia and sodium benzoate is probably the first meaningful tool that we have had to influence this target," said John Krystal, M.D., Editor of Biological Psychiatry.

Although more studies are needed to learn how sodium benzoate enhances clozapine treatment in these patients, Dr. Krystal says that "this study highlights the importance for schizophrenia treatment of understanding the molecular switches that can be thrown to normalize brain circuit function."

Reference

Chieh-Hsin Lin, Ching-Hua Lin, Yue-Cune Chang, Yu-Jhen Huang, Po-Wei Chen, Hui-Ting Yang, Hsien-Yuan Lane. 'Sodium Benzoate, a D-amino Acid Oxidase Inhibitor, Added to Clozapine for the Treatment of Schizophrenia: A Randomized, Double-Blind, Placebo-Controlled Trial.' Biological Psychiatry (2018). https://doi.org/10.1016/j.biopsych.2017.12.006.

Source-Medindia