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[Download the NAMI omega-3 fatty acids fact sheet.]

Omega-3 Fatty Acids and Mental Illness

What are omega-3 fatty acids?

Omega-3 fatty acids are a group of related chemicals that have been identified in a number of different foods. High quantities of omega-3 fatty acids have been found in many types of seafood—specifically fish—which has led some people to commonly refer to these compounds as fish oil. Two specific omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been identified as being useful in the treatment of both medical and mental illnesses. While the exact manner in which these chemicals are beneficial is not known, it is thought that they are helpful in decreasing systemic inflammation, a potentially harmful process that occurs throughout the brain and body.

Omega-3 fatty acids are sometimes used to treat cardiovascular disease. Specifically, when used as a vitamin supplement, omega-3 fatty acids have been found to treat high cholesterol and to lower the risks of heart disease in many people. Omega-3 fatty acids have also been studied for use in people with asthma, dementia and a number of other conditions; however, their effects in these illnesses are less clear.

What is the connection between omega-3 fatty acids and mental illness?

Extensive scientific research has shown that mental illnesses are not caused by one single thing. When a person with biological risk factors (e.g., the presence of other medical illnesses or certain genes that are associated with mental illness) experiences environmental adversity—a stressful life event—this may trigger the development of mental illness. Furthermore, it is clear that biological and environmental factors work together on a biochemical basis. One such example is how systemic inflammation—a biological process that is directly related to an individual’s stress level—puts a person at risk for mental illness. Omega-3 fatty acids are known to decrease the effects of systemic inflammation. This is what some scientists think makes omega-3 fatty acids an effective treatment for certain people with mental illness. Some studies have shown that higher doses of EPA omega-3 fatty acids—as opposed to DHA—may be more useful in treating mental illnesses, although the specifics of this remain an area of ongoing scientific research.

Scientific research has also shown that certain people are at risk of developing schizophrenia and other psychotic illnesses based on a number of factors, one of which is inflammation. For a young person who may be experiencing certain symptoms of psychosis for the first time, treatment with omega-3 fatty acids has been shown to decrease their risk of developing a more chronic and severe form of schizophrenia. For people already living with schizophrenia, omega-3 fatty acid supplementation has not been consistently shown to be as effective as it is for people who have not yet developed this illness. However, because many people with schizophrenia are at risk of developing metabolic syndrome, supplementation with omega-3 fatty acids can be helpful in decreasing the risk of heart disease associated with this condition.

Many people with depression will also benefit from supplementation with omega-3 fatty acids. Scientific studies have shown that people with depression often have increased systemic inflammation that can be improved with omega-3 fatty acid supplementation. Furthermore, a variety of research has suggested that people with depression—and people who commit suicide—may be more likely to have low levels of omega-3 fatty acids in their brains. Therefore, it is not surprising that scientific studies have shown that many people with depression will experience a decrease in their symptoms when regularly taking omega-3 fatty acids. One specific area where omega-3 fatty acids may be a treatment of choice is for pregnant women and those with postpartum depression. This is because omega-3 fatty acids are likely beneficial for both the mother and her developing child.

There is less scientific data to support the regular use of omega-3 fatty acid supplementation in people with bipolar disorder, borderline personality disorder and ADHD. In spite of this, omega-3 fatty acids may play an important role as an adjunctive treatment—in addition to a personís regular psychiatric medications—in these and other mental illnesses.

Are there any important side effects of omega-3 fatty acid supplements?

Omega-3 fatty acids are thought to be relatively safe for most people. Scientific studies have suggested that certain people may be at increased risk of bleeding when taking these supplements. This is particularly important for people undergoing surgery or for those with coexisting medical illnesses that affect the body’s ability to stop bleeding (e.g., clotting diseases such as hemophilia). Some people who use omega-3 fatty acids will also experience a strange fishy taste in their mouth, an upset stomach, a change in their bowel movements or other associated gastrointestinal side effects.

Unlike some other herbal and complementary medicines (e.g., St. John’s wort), omega-3 fatty acids do not interact with most other medications. One notable exception is that people taking other medications affecting the blood—including aspirin, non-steroidal anti-inflammatory drugs (e.g., ibuprofen), and blood-thinners such as warfarin (Coumadin)—may be at increased risk of excessive bleeding.

For many people, omega-3 fatty acids will be most useful as an additional treatment along with their other regularly prescribed psychiatric medications (e.g., antidepressants and antipsychotics). As with any other medication, herbal supplement or medical treatment, all individuals are advised to discuss omega-3 fatty acids with their physicians. Some physicians may be more or less knowledgeable regarding this treatment while others may have a specific brand of omega-3 fatty acid supplement that they recommend. In summary, while this supplement is not approved by the FDA for treatment of mental illnesses, it has been shown to be a useful additional treatment for many people living with depression, psychosis and other conditions.

Reviewed by Jacob L. Freedman, M.D., and Ken Duckworth, M.D., April 2013

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