Fish oils for mental illness: don’t waste your money.

And more than that, concentrate  efforts on things that are more likely to help now and in the future.

I’m disturbed by the idea that fish oils are a  good idea for ‘depression to schizophrenia’ as evidenced by this article. There are several reasonable theories as to why fish oils might help mental health, but the problem is that theory is not enough. The history of medicine is littered with great ideas that did harm or no good.

The best way to get a handle on what the studies show is to read the evidence, all of it. This would take a very long time. The additional problem is that trials showing a benefit are more likely to be published, and to be publicised, than trials showing they don’t work. So you have to dig deep, and the best and fairest way is to look for Cochrane reviews. These are reviews of all the evidence on the subject, and pull together all trials – not just tiny trials that were positive and gained a lot of coverage – but also negative trials.

Cochrane is pretty clear.

For schizophrenia, they say the evidence is “inconclusive”.

For bipolar disorder, there is “insufficient evidence”

For borderline personality disorder, “Total BPD severity was not significantly influenced by any drug”

I can’t find a Cochrane review for the effects of fish oil on unipolar depression, but this review suggests that the possible helpful effects are “potential” only, and needs proper trials. A previous systematic review had found “little support” for fish oils in depression.

And while we’re here, a reminder that Cochrane have also said that ” there is no good evidence to support the use of dietary or supplemental omega 3 PUFA for the prevention of cognitive impairment or dementia”.

It would take me time I don’t currently have to go through the rest of the article.

It’s easy to be sold the idea that the solution to hard problems can be delivered in a pill. Many medications do have a useful and important role to play in treating mental illness. But many do not, and just because something is ‘complementary’ (i.e. not proven to work) does not make it safe. It also serves to distract us from the things that do matter, and it means that we are pushed to a dichotomy in the evidence for what we take – one standard for prescribed drugs, another for what we buy. We should be demanding high quality evidence for both. That’s why I don’t recommend fish oil supplements to  people who have mental health conditions.


Update: A quick word on the B vitamins for brain function.

I don’t recommend them. The Optima research project has not proven that B vitamins will prevent dementia.

It’s also notable that Food for the Brain, an organisation who promote dubious non evidenced tests and who advertise Patrick Holford’s books, and who direct people to buy expensive non evidenced supplements, have, as their chair, David Smith. Professor Smith is the founding director of Optima.

(I’ve also written about Food for the Brain here in the BMJ.)

Vitamins and supplements are not the cuddly alternatives to nasty pharmaceuticals. All need to be treated with the same cautions, and all need good evidence of efficacy.


2 Responses to “Fish oils for mental illness: don’t waste your money.”

  1. Mary Palmer May 28, 2012 at 10:59 pm #

    I don’t know about the general population, mental health problems and Vitamin B12 in particular. But as a patient with pernicious anaemia. I know my mental health deteriorates when I do not get sufficient B12. Which l don’t on the NHS. I have resorted to purchasing injectable B12 online because the current recommended treatment regime is followed rigidly by my GP. Rather than treating my symptoms.

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