Fish oil pills may be able to spare some young people with signs of mental illness from a progression into fully developed schizophrenia, according to a preliminary study of 81 patients in Austria.

The study adds to evidence suggesting that severe mental illness may be prevented with intervention. The researchers are starting a larger study in eight cities, hoping to replicate the findings, which appear in the February issue of Archives of General Psychiatry, released Monday.

A severe mental illness, schizophrenia affects adolescents and young adults. Some 2.4 million Americans have the disorder, which is treated with antipsychotic medication.

“Schizophrenia is among the most mysterious and costliest diseases in terms of human suffering, so anything that gives some hope to avoid this is great,” said lead author Dr. G. Paul Amminger, formerly in Vienna and now at the Orygen Youth Health Research Center at the University of Melbourne in Australia.

Researchers have wondered if the disease could be stopped before it overpowers a person’s grip on reality. Studies have tried antipsychotics in select young people, but side effects pose ethical questions, and results have been mixed.

Researchers in the new study identified 81 people, ages 13 to 25, with warning signs of psychosis, including sleeping much more or less than usual, growing suspicious of others, believing someone is putting thoughts in their head or believing they have magical powers. Forty-one were randomly assigned to take four fish oil pills a day for three months. The other patients took dummy pills.

After a year of monitoring, 2 of the 41 patients in the fish oil group, or about 5%, had become psychotic, or completely out of touch with reality. In the placebo group, 11 of 40 became psychotic, about 28%.

No one knows what causes schizophrenia but one hypothesis is that people with the disease don’t process fatty acids correctly, leading to damaged brain cells. Omega-3 fatty acids in fish oil could help brain cells repair and stabilize, the researchers speculate.

Dr. Janet Wozniak of Harvard Medical School said the findings might reasonably cause psychiatrists to recommend fish oil to some patients because there are known benefits and little risk.