Checking the meditation industry's scientific claims
Dr. Madhav Goyal talked to Bob McDonald about the science behind claims made both by the meditation industry, as well as the scientific literature on Headspace, the meditation app.
The following interview has been edited and condensed for clarity.
Bob McDonald: Let's get right to some of the claims that Headspace makes. Their first one is "a U.S. study found that just four days of 20 minutes per day mindfulness training improve working memory and the ability to sustain attention."
How much confidence do you have in that claim?
Dr. Madhav Goyal: I would put low confidence in that.
BM: Can you take me through that. Why is the confidence low?
MG: So when we're evaluating these sorts of claims we generally don't rely on one study. Let me give you a scenario. This one study shows this claim. Let's suppose that there are nine or ten more studies that are done and all nine or ten of those also support the claim that the first study made.
That gives us a lot of confidence that the claim that the first study made is actually real. Now let's suppose on the other hand that none of them found the same results that the first study did. Then our impression of the first study is that those effects are probably not real.
I think that those (memory and attention results) are interesting findings. I think that they are worthy of replicating. And I'd like to see that there are more studies done that do replicate those results.
BM: How did the Headspace mindfulness sessions compare with the more traditional mindfulness sessions that are done?
MG: For this particular study, I think they were both fairly equivalent. There was a little more effect in the longer term mindfulness but they were fairly equivalent in terms of the number or the proportion of people that were getting up to offer their seats.
BM: A recent review of nearly 50 scientific studies found that mindfulness was as effective an antidepressant in helping depression but with no side effects. Now Dr. Goyal this is actually your 2014 review. So do your findings mean that people with depression who are on medication should throw away their meds in exchange for mindfulness meditation?
MG: No. There are a couple of caveats to that statement. First our review did not review head to head comparisons between mindfulness and antidepressants, so we wouldn't make that claim that they are as effective as antidepressants. What we're saying is that we were finding effect sizes that were as large with the mindfulness programs in reducing symptoms of depression as what other studies have found, when they used antidepressants.
The second caveat is that the studies that we reviewed were looking at a variety of populations; people who had heart failure or fibromyalgia or irritable bowel syndrome or HIV, so forth. There were only a few of them that had actual clinical depression.
So most of the people that were in these studies would have had mild to moderate symptoms of depression not severe symptoms of depression.
But that said what we were finding was that the degree of effect in reducing symptoms of depression, mild symptoms of depression, it was about the same as what other studies seemed to be reporting with antidepressants in similar populations.
BM: So then are you saying that this is an effective tool for depression?
MG: I think that this is an effective tool. You know in our review we were doing two things. We were looking at what was the magnitude of effect and then we were looking at how confident we were that this effect was real.
And we rated our confidence on a four point scale. It was high confidence or high strength of evidence. That meant that we were so confident everything looks so consistent that we didn't think any further studies would add any more information to our estimates.
And we did not come up with a high confidence for any meditation program for any outcome. Then there was moderate low and insufficient, and we found that there was moderate strength of evidence that mindfulness programs improved symptoms of depression, anxiety and pain.
And this is above and beyond a placebo effect. So I think that there is pretty good evidence that mindfulness programs are useful for those three conditions and that they can be used as an adjunct to whatever therapies, you know antidepressants or other therapies, that people are using.
BM: Now you also looked at the available science specifically looking at the Headspace program. So in general then what are your thoughts on the effectiveness of programs like Headspace?
MG: Well I think that the studies that have been done are few. They're relatively small and that there appears to be some preliminary evidence that these programs do improve certain psychological outcomes such as some symptoms of anxiety and depression.
But I think that the overall strength of evidence for these kinds of programs is still low. And I think that further study would help to elucidate whether or how effective these programs are.