Omega-3 fatty acids may prevent the development of full-blown schizophrenia in people who are at high risk of the disease, new research suggests.

What's more, omega-3s seemed to prevent the study participants from developing psychosis for several years after people stopped taking them, according to the study.

The findings suggest a possible treatment for people at risk of developing this notoriously difficult-to-treat condition, the researchers said. Currently, people with schizophrenia are treated with antipsychotic medications, but the drugs don't work for everyone, have side effects, and typically have to be taken for life, meaning they aren't suitable for people who have some symptoms, but no diagnosis of schizophrenia.

"There may be alternatives to antipsychotic medication in treating and preventing the onset of psychotic disorder," said study co-author Dr. G. Paul Amminger, a psychiatrist at the University of Melbourne in Australia. "Omega-3 fatty acids are basically a stigma-free and even longer-term preventive strategy with minimal associated risks and side effects." [6 Foods That Are Good for Your Brain]

However, the study was relatively small, so follow-up work is needed to confirm the findings, Amminger said.

Omega 3 and the brain

Omega-3 fatty acids are commonly found in foods such as fatty fish, eggs and walnuts, and several early studies suggested the compounds may quiet inflammation in the body. Some research has found that omega-3s improve heart health and chronic conditions such as rheumatoid arthritis and depression. (However, a large, recent study of omega-3s showed they failed to improve heart health, according to findings published in 2014 in the journal JAMA Internal Medicine.)

People with schizophrenia often have high levels of inflammatory chemicals in their body, but low levels of omega-3 fatty acids in their blood. Amminger and his team wondered whether brain inflammation partly causes schizophrenia, and so they decided to test whether giving omega-3 supplements, such as fish oil, could help prevent inflammation and thereby stop schizophrenia from developing in the first place.

The researchers recruited 81 teenagers and young adults who were at high risk of developing full-blown psychosis within a year. The youngsters, who were between ages 13 and 25, all had some of the earliest symptoms of schizophrenia. For instance, some were hearing voices or hallucinating, but these symptoms lasted at most a few days. Others were having delusions that someone was trying to harm them, but they were able to quickly disregard those fleeting thoughts. (About 30 percent of adolescents and young adults with such symptoms will go onto develop clinical schizophrenia or psychosis, Amminger said.)

Half of the group took an omega-3-rich fish oil supplement for 12 weeks, while the other half received a placebo pill that was laced with a tiny hint of fish oil. The team followed the study participants for seven years.

Just 10 percent of the patients who took the fish oil supplement developed schizophrenia, compared with 40 percent of the patients in the control group, the researchers found.

The study was fairly small and it's not clear why the omega-3s may have benefited the patients, but one possibility is that the compounds interrupted the cascade of inflammatory chemicals at just the right stage of the disease.

"One explanation is it puts you on a different developmental trajectory," Amminger told Live Science. "So when you are able to interrupt this cascade, which leads to a full threshold psychotic disorder, it seems you don't experience the same amount of risk."

Because most high-risk patients do not go on to develop schizophrenia, doctors typically don't prescribe a low-dose antipsychotic to people experiencing these types of symptoms, Amminger said. Antipsychotics are effective, but cause weight gain, high cholesterol, and diabetes, Amminger said.

By contrast, omega-3 supplements have few known side effects, Amminger said.

Still, follow-up work needs to confirm the findings. A handful of other studies are evaluating omega-3 supplementation and its effect on schizophrenia, so those can provide a more definitive answer, Amminger added. 

The findings were published today (Aug. 11) in the journal Nature Communications.

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