Nasal sprays containing the hormone oxytocin, nicknamed the “cuddle chemical” because it helps mothers bond with their babies, have helped people with schizophrenia.
Although the 15 participants used the sprays for three weeks only, most reported measurable improvements in their symptoms in this the first trial to test oxytocin in schizophrenia. “It’s proof of concept that there’s therapeutic potential here,” says David Feifel at the University of California in San Diego, head of the team running the trial.
Each participant received oxytocin or a placebo for three weeks, then the opposite treatment for three weeks with a week break in between.
On the basis of two standard tests for schizophrenia, taken before and after each block of treatment, participants averaged improvements of around 8 per cent when taking the oxytocin compared with the placebo (Biological Psychiatry, DOI: 10.1016/j.biopsych.2010.04.039).
The effects didn’t kick in until the final week, suggesting that it takes a while for the hormone to begin acting. “Standard antipsychotic drugs increase their efficacy several weeks later too, so oxytocin fits that profile,” says Feifel.
Feifel thinks that oxytocin is dampening down the excessive production of the neurotransmitter dopamine, which can trigger schizophrenic symptoms such as hallucinations. He says the rationale for treating people came from his own team’s studies showing that oxytocin could relieve a form of psychosis in mice, and research showing that people who sniffed nasal sprays of oxytocin became more trusting, which could ease paranoia symptoms in schizophrenia.
Feifel is seeking approval from the US National Institutes of Health for a larger trial testing oxytocin at a range of doses, and over a longer time.
“This work provides compelling data on the utility of oxytocin as a treatment for schizophrenia,” says Heather Caldwell of Kent State University in Ohio, co-author of a study in 2008 showing that “knockout” mice unable to make oxytocin were more prone to a form of psychosis.
By: Andy Coghlan / Courtesy: New Scientist